Search PubMed⌕ Search

Biomedical subjects

K Johansson

Publications and source records attributed to K Johansson.

At least 163 records · Page 9Linked to original sources
PubMed1986

Assessment of small-bowel ischemia by laser Doppler flowmetry. Some case reports.

Laser Doppler flowmetry was used for intraoperative assessment of intestinal blood flow in five patients with small-bowel ischemia. In two patients with mechanically caused ischemia, bowel resection could be limited or avoided after flowmeter recordings. In two patients with mesenteric vascular occlusion, the flowmeter recording confirmed the macroscopic impression of irreversible gangrene. In a third subject with mesenteric vascular occlusion the extent of severe ischemia was clinically underestimated compared with the results obtained with the laser Doppler flowmeter. We conclude that, with further experience and development, laser Doppler flowmetry has great potential as a useful method for objective intraoperative assessment of blood flow in patients with small-bowel ischemia of various origins.

Aged↗
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↗
PubMed1985

Brain metabolism in deep controlled hypotension in neurosurgical patients.

Changes in the lactate and pyruvate levels and lactic dehydrogenase activity in the cerebrospinal fluid were followed in 56 patients anaesthetised for neurosurgery. Mean arterial blood pressure (MAP) was reduced in these patients from about 90 to about 35 mm Hg. This allowed to safely place a clip at a brain artery aneurysm. In spite of deep hypotension, ischaemia described by other authors in such cases was never observed. Changes in lactate and pyruvate concentrations, lactate/pyruvate ratio and lactic dehydrogenase activity justify the conclusion that we were dealing with an undisturbed metabolism of the brain tissue. The levels of metabolic parameters, even when increased in hypotension, fell well within the range of physiological values. Attention is called to the fact that partial oxygen pressure in arterial blood during controlled hypotension was about 100 mm Hg, a value considered as limiting to oxygen metabolic transformation within the central nervous system in deep hypotension. We also suggest a different mechanism of passage of lactates and pyruvates through the blood-brain barrier.

Adult↗
PubMed1984

A vaginal temperature registration system.

A radiotelemetric method for measurements of vaginal temperature in the home milieu is presented. Registrations from two subjects show that vaginal temperatures vary up to and about 1 degree C nighttime. Initially, on going to bed, vaginal temperature drops. A further distinct drop occurs with any kind of experienced sexual arousal, reaching a minimum when and if orgasm is achieved. At rest, vaginal temperature varies rather regularly and in concurrence with rectal temperature throughout the night. The initial temperature drop may be caused by decrease in blood flow, whether determined by metabolic or by postural factors. Temperature variations of the resting vagina may be concomitant with other circadian temperature rhythmic variations, while the temperature decrease during sexual arousal may be caused by vaginal wall edema and/or possibly by change of position of the uterus. The main point of the investigation is methodological: it is felt that the method can provide clinicians and researchers with a tool by which important vaginal physiologic events can be measured under somewhat more optimalized circumstances than those offered by the laboratory milieu.

Adult↗
PubMed1982

Evaluation of a dynamometer for measurement of isometric and isokinetic torques.

A modified version of the original Cybex II dynamometer with a temperature compensated strain gauge transducer has been evaluated. It was found that the calibration constant was dependent of the vertical load of the device. The ratio (k) between the applied and the recorded torque is angle independent during extension and k is equal to 1.18 and during flexion k is angle dependent and can be expressed as k = -.0008 theta + 1.208, where theta is the angle of flexion.

Biomechanical Phenomena↗
PubMed1980

Sperm morphology and in vitro viability in diluted semen in relation to fertility of AI boars.

Examination of sperm morphology and assay of in vitro sperm viability by use of a thermoresistance test, incubation with ouabain and assay of ASAT-release was performed in 10 ejaculates from each of 10 boars during a 7-month period. The boars were routinely used for AI during the period and the results of the various laboratory assays were related to the fertility of the boars.

Animals↗
PubMed1978

Viral DNA sequences and gene products in hamster cells transformed by adenovirus type 2.

Complementary strand-specific adenovirus DNA of full length or from endonuclease BamHI fragments was used as a probe to estimate the fractional representation and abundance of viral sequences in five hamster cell lines (Ad2HE1-5) transformed with UV-inactivated adenovirus type 2. The fraction of the viral genome present in the five transformed cell lines varied from 44% in the Ad2HE5 cell line to 84% in the Ad2HE3 cell line. The number of viral DNA copies per diploid cell equivalent ranged from 1.8 in the Ad2HE1 line to 7.1 in the Ad2HE4 line. In vivo labeling with [35S]methionine followed by immunoprecipitation with an antiserum against adenovirus type 2 early proteins revealed virus-specific polypeptides with molecular weights of 42,000 to 58,000 in extracts from all five hamster cell lines. Several other early viral polypeptides were detected in some of the adenovirus type 2-transformed hamster cell lines.

Adenoviruses, Human↗
PubMed1977

Reassociation of complementary strand-specific adenovirus type 2 DNA with viral DNA sequences of transformed cells.

Complementary strand-specific adenovirus DNA, either full length or from restriction enzyme cleavage fragments, was used to estimate the fractional representation and abundance of viral sequences in two adenovirus type 2 (Ad2)-transformed rat cell lines, A2F19 and A2T2C4. The reassociation method introduced is based on the linear relationship, after exhaustive hybridization, between the inverted fraction of hybrid DNA and the molar ratio of probe to cellular DNA in the reaction mixture. The amount of viral DNA in A2F19 cells represents 12 to 14% of the viral genome at a level of around seven copies per diploid cell equivalent. For the cell line A2T2C4, the pattern of integrated viral DNA sequences is more complex. With full-length Ad2 DNA strands as a probe, about 56% of the probe was represented in cellular DNA. When each of the four BamHI fragment strands of Ad2 DNA was used as a probe, the fraction of the viral DNA present also amounted to around 56% with one to five copies from different regions of the viral genome. The results demonstrate the advantage of using strand-specific viral DNA as a probe in reassociation analysis with denatured cell DNA. The method should be useful in any system in which complementary strand separation of viral DNA sequences can be achieved.

Adenoviruses, Human↗
PubMed1976

Purification of adenovirus messenger ribonucleic acid by an aqueous polymer two-phase system.

An aqueous polymer phase system containing 6.3% (w/w) dextran and 3.5% (w/w) poly(ethylene glycol) in 10 mM phosphate buffer (pH 8.0) was developed to select RNA-DNA hybrids from unhybridized RNA. The top phase of this phase system, which contains DNA and the RNA-DNA hybrids, can be used to purify adenovirus messenger RNA both early and late in the infectious cycle. The hybrids can be melted by heat in the top phase and the messenger RNA selected by oligo(dT)cellulose chromatography whereupon the polymers and the DNA percolate and the polyadenylated messenger RNA absorb to the column. The isolated messenger RNA appears to be almost quantitatively recovered at a purity from 70 to 90% depending on the concentration of the specific messenger RNA in the starting material. Early and late viral messenger RNA were selected on the complementary strands of adenovirus DNA according to this procedure.

Adenoviruses, Human↗
PubMed1976

Computer classification of ST and T in averaged ECGs at rest and exercise.

A computer program for ST and T classification at rest and exercise is described. The automatic ST classification was based on the modification of the Minnesota code suggested by Punsar et al. The T wave classification was based on the Minnesota code of 1968. Recordings at rest, during and after exercise from 217 exercise tests were visually classified by two observers, and their result was compared to the computer's. Computer-observer comparisons yielded no more disagreements than between-observer comparisons. There were computer-observer disagreements caused by computer errors in 3% of the records. The repeatability of the computer's ST classification on records taken during exercise was better than that of one visual observer. Within-computer and within-observer repeatability appeared to be negatively affected by remaining noise in the average.

Adult↗
PubMed1976

A system for computer-assisted ECG recording at rest and exercise.

Great investments have been made in computerized ECG interpretation but little attention has been paid to rationalization of such costly activities as recording, labelling and mounting ECGs, and still less to the presentation of ECGs. A system for such tasks is described. It includes a PDP8/E computer and modified ink jet ECG recorders, which write alphanumeric text and function as analogue input- and output-devices for the computer. On-line computer service is given independently to two laboratories for ECG at rest, VCG or exercise ECG. After averaging the ECG signal, the computer writes out a properly labelled ECG in an easily surveyable form. The visual interpretation of the ECG is entered and is then written on a new sheet together with the averaged 12-lead ECG and a rhythm strip. In exercise testing, the computer records and processes the ECG at predetermined intervals. The processing includes an automatic ST classification. A summarized presentationof the ECG before, during and after exercise allows easy visual identification of ECG changes. Experience of the system has mainly been obtained from 2 years of routine exercise ECG recording and to a limited extent from ECG and VCG recording at rest.

Cardiology↗
PubMed1974

Relationship of mRNA from productively infected cells to the complementary strands of adenovirus type 2 DNA.

The complementary strands of adenovirus type 2 (Ad2) DNA were separated by buoyant density gradient centrifugation with poly (U, G). The complementary strand DNA was shown to remain intact through the course of strand separation. The l-strand of Ad2 DNA, appearing in the less dense complex with poly (U, G) in neutral CsCl density gradients, was shown to have a buoyant density in alkaline (pH 12.5) CsCl density gradients which is 2 to 3 mg per ml greater than that of its complement (h-strand). Renaturation of purified complementary strand DNA was observed only in mixtures of h- and l-strand DNA, and then with the second-order reaction rate expected for Ad2 DNA. Hybridization of the complementary strands of Ad2 DNA with cytoplasmic mRNA isolated from infected HeLa cells was performed in liquid phase and analyzed by hydroxylapatite chromatography. Before viral DNA synthesis (6 h after infection), 13 to 18% of the h-strand and 30 to 35% of the l-strand were represented in viral mRNA. Late (18 h) after infection the mRNA represented 20 to 25% and 63 to 68% of the h- and l-strands, respectively. Most, if not all sequences present in viral mRNA before viral DNA synthesis were also present in the cytoplasm late in infection.

Adenoviridae↗
PubMed1973

Hydroxyapatite chromatography and formamide denaturation of adenovirus DNA.

Denatured adenovirus DNA was retained by hydroxyapatite columns under conditions generally used for selective retention of double-stranded DNA, probably due to several partially complementary sequences within single-stranded DNA. It was found that addition of formamide reduced the fraction of sonically treated, denatured adenovirus DNA bound to hydroxyapatite from about 30% to less than 1%. This led to a study of the effect of formamide on the melting temperature (T(m)) of double-stranded DNA in solution or bound to hydroxyapatite. The T(m) of DNA decreases 0.56 C/1% formamide, a value determined in buffered solutions with purified formamide.

Adenoviridae↗