Search PubMed⌕ Search

Biomedical subjects

J Wolf

Publications and source records attributed to J Wolf.

At least 235 records · Page 13Linked to original sources
PubMed1990

Suppression of the malignant phenotype in somatic cell hybrids between Burkitt's lymphoma cells and Epstein-Barr virus-immortalized lymphoblastoid cells despite deregulated c-myc expression.

To approach the question whether the absence of specific cellular gene functions may be involved in Burkitt's lymphoma pathogenesis, somatic cell hybrids were established between a malignant Epstein-Barr virus (EBV) positive Burkitt's lymphoma cell line (BL 60) and a nonmalignant EBV-immortalized lymphoblastoid cell line (IARC 277) derived from the same individual. The hybrids revealed a near tetraploid karyotype including one copy of the 8q+ chromosome resulting from the Burkitt's lymphoma-specific translocation t(8;22) in addition to three apparently normal copies of chromosome 8. Although the hybrid cells exhibited the deregulated c-myc expression pattern of the parental Burkitt's lymphoma cell line with highly abundant transcripts originating from the 8q+ chromosome, their growth characteristics in tissue culture as well as in nude mice were identical to that of the parental nonmalignant lymphoblastoid cell line. These data indicate that, at least in the system described here, the malignant phenotype of Burkitt's lymphoma cells can be suppressed by introduction of an additional set of apparently normal chromosomes from the same individual and that EBV infection and c-myc deregulation may not be sufficient for maintenance of the malignant phenotype.

Animals↗
PubMed1990

The mandibular infected buccal cyst (paradental cyst). A radiographic and histological study.

Mandibular infected buccal cysts occur on the buccal and distal aspects of the roots of partly or fully erupted mandibular molars with vital pulps. In the present investigation six cases associated with mandibular first and second molars were studied. The cysts were lined with a non-keratinised squamous epithelium with a mixed inflammatory cell infiltrate in the connective tissue. The clinical and microscopic features were similar to those of previously reported paradental cysts. The inflammation always present in these cysts may have an important role in their pathogenesis. It may induce periodontal pocketing, which may lead to hyperplasia and cyst formation in adjacent odontogenic epithelium, which may be either remnants of the reduced enamel epithelium or cell rests of Malassez.

Adolescent↗
PubMed1990

Is cyclosporin A an inhibitor of drug metabolism?

1. The potential for a drug interaction between cyclosporin A and midazolam was investigated since both compounds appear to be metabolized by the same cytochrome P-450 isoenzyme. 2. In vitro evaluation of the binding of cyclosporin A to rat microsomal cytochrome P-450 indicated a Ks-value of 0.4 microM. In further studies with rat liver microsomes IC50-values of 6, 8 and 70 microM cyclosporin A were determined for the inhibition of the metabolism of midazolam to its alpha-OH-,4-OH- and di-OH-metabolites, respectively. 3. Comparative studies with human liver microsomes indicated IC50-values of approximately 300 microM for the formation of alpha-OH-midazolam and of 65 microM for the formation of 4-OH-midazolam. 4. The pharmacokinetics of a single intravenous dose of midazolam (0.075 mg kg-1) was studied in nine patients receiving cyclosporin A to prevent rejection of their transplanted kidneys. The average steady state blood concentrations of cyclosporin A, measured by r.i.a. using a specific monoclonal antibody, varied during a dosing interval between 175 and 600 ng ml-1. 5. In these patients the hepatic elimination of midazolam was characterized by a mean t1/2 (+/- s.d.) of 2.3 +/- 1.2 h and a plasma clearance (CL) of 414 +/- 95 ml min-1. These values were not different from those of normal human subjects (t1/2 = 1.5 to 4 h, CL = 350 to 700 ml min-1). 6. From the results of the in vitro experiments it is concluded that cyclosporin A may potentially inhibit drug metabolism.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

The effect of the benzodiazepine antagonist flumazenil on regional cerebral blood flow in human volunteers.

The influence of the benzodiazepine antagonist flumazenil on regional cerebral blood flow (rCBF) was investigated in ten healthy, alert volunteers. The design was a randomized, placebo-controlled, double-blind, cross-over study. rCBF was measured by 133-Xe inhalation and single photon emission computerized tomography, SPECT, immediately before, and 5 and 35 min after intravenous injection of flumazenil 1.0 mg or placebo. In addition, mean arterial blood pressures or PaCO2, rCBF were analysed for changes in various regions of interest (RoI). No alterations were found either in the global CBF or in rCBF in RoI after flumazenil injection. The results showed that a clinically active dose of flumazenil did not directly affect the cerebral circulation in the normal brain and indicated absence of significant intrinsic activity of the drug.

Adult↗
PubMed1990

Clinical and panoramic assessment of marginal bone loss. A cadaver study.

The purpose of this study was to investigate the reliability of panoramic tomography for the assessment of marginal alveolar bone loss. The study was conducted with 20 human cadavers, in relation to 123 of their teeth. Panoramic tomograms of the cadaver dentitions were taken using a Zonarc radiographic apparatus. Root lengths and bone losses were measured mesially and distally from the panoramic tomograms. Bone loss was also measured by surgical exposure of the marginal bone. Root length was also measured after extraction of the tooth. After allowing for the vertical magnification, radiographic bone loss values were found to be about 0.8 mm (27%) less than clinical values. This difference was statistically significant only in the incisor area. It was almost significant in the premolar region. It is therefore concluded that panoramic tomography is sufficiently reliable for clinical assessment of alveolar bone loss but that the bottom of periodontal pockets always tends to be somewhat deeper than the radiographically visible defect.

Adult↗
PubMed1990

[The relationship between udder health and milk production in SMR cows].

Analyses made of seven dairy units revealed that clinically manifest udder inflammations had occurred once or repeatedly to 23.9 per cent of all cows in their first lactation and to 34.0 percent during the fourth lactation. Cows with no clinical udder inflammation in the first and second lactations were superior by 205 kg of milk to animals in whom such inflammations developed during the second lactation. Correlation coefficients between udder health and milk yield were between -0.22 and 0.32 and were likely to suggest that in the long run improvement of the genetic potential for milk yield was accompanied by deterioration of udder health. Therefore, udder health should be included by stabilising selection in Friesian dairy cattle breeding in the GDR. A sufficient breeding potential will be left for milk yield parameters, as was shown by simulated selection experiments.

Animals↗
PubMed1989

A radiological study of degenerative vascular changes in the external carotid region and carotid bifurcation.

In a series of 79 autopsies performed on subjects aged from 18 to 95 years occlusions in the external carotid, maxillary and inferior alveolar arteries were rare: only two cases were found in the maxillary and one in the inferior alveolar arteries. Tortuosity of the arteries increased with age, being most extensive in the external carotid and least in the inferior alveolar artery. Variations in the diameter of the maxillary artery occurred in 11 persons (14%), the incidence increasing with age. The youngest person showing such changes was aged 55 years. The average diameter of the arterial lumen of the inferior alveolar artery decreased with advancing age. This narrowing of the lumen also correlated with the loss of teeth. Calcified atherosclerotic plaques in the carotid bifurcation were present in 59% of the cases studied. In persons aged over 60 years a correlation was found between the carotid calcifications and coronary artery disease.

Adolescent↗
PubMed1989

Florid cemento-osseous dysplasia (gigantiform cementoma) in a Caucasian woman.

The present study reports a case of an uncomplicated florid cemento-osseous dysplasia in a 39-year-old Caucasian woman. The extensive dysplastic lesions affected all jaw quadrants and both radio-opaque and lytic lesions were demonstrated radiographically. Histopathological studies revealed calcified, partly acellular cementum-like tissue. All clinical, radiographic, biochemical and histological features were suggestive of the diagnosis of florid cemento-osseous dysplasia.

Adult↗
PubMed1989

[Follow-up of perinatal HIV infection].

The clinical course of a perinatal HIV infection in a 3 1/2-year-old girl is presented. The girl became HIV-positive at the age of 6 months, at about the same time as her mother. She is receiving continuous prophylactic treatment with immunoglobulins and cotrimoxazol. The pathological findings and the stage according to the classification of the Centers for Disease Control are discussed.

Child, Preschool↗
PubMed1988

Bone resection in patients with mandibular sarcoma.

Thirty-nine cases of mandibular sarcoma were reported to the Finnish Cancer Registry during the period 1953-1985. In 11 of these (nine osteosarcomas, one chondrosarcoma, one leiomyosarcoma), the pre- and postoperative radiographs were still available, and they were analyzed in order to evaluate the radicality of the primary surgical procedure in relation to recurrences during the follow-up. On the basis of several radiological details, the resection was considered inadequate in seven cases. One operation was probably inadequate because of rather scanty margins. In only three cases had an adequate primary resection with proper safety margins been performed. All of the seven patients with inadequate primary surgery had recurrence and five of them died of local disease or metastases, whereas only one of the three patients with adequate resection had recurrence in adjacent soft tissues. It is concluded, that radiological findings of mandibular sarcoma that often are missed include widening of the mandibular canal and disappearance of the lamina dura. Proper preoperative radiological examination resulting in more radical primary surgery would certainly decrease the recurrence and mortality rates in patients with mandibular sarcoma.

Adult↗
PubMed1988

Early retirement and work after retirement. Implications for the structure of the work society.

Early exit from the formal work force and the lengthening of life in retirement pose new questions, both on the level of social structure and on that of emerging life-styles. Based on two empirical studies - one of workers who choose the new pre-retirement scheme, and one of retirees who engage themselves in organized work-like activities - we examine some of the consequences of this process. The studies combine qualitative and quantitative research methods and pay special attention to the biographical dimension. Our results show that under the pressure of the labor market, new forms of "flexible" or "gradual" transition to retirement empirically turn out to be retirement at the earliest possible moment. For the workers, early retirement is ambivalent: it threatens their concept of a "full work life", which is based on the time-table of the socially institutionalized normal biography; but this is offset by their desire to leave stressful work situations at least where the schemes for early retirement are financially and morally acceptable.

Aged↗