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Biomedical subjects

M Stark

Publications and source records attributed to M Stark.

At least 109 records · Page 6Linked to original sources
PubMed1990

Isolation by polymerase chain reaction of a cDNA whose product partially complements the ultraviolet sensitivity of xeroderma pigmentosum group C cells.

A xeroderma pigmentosum (XP) cell line from complementation group C has been complemented to attain ultraviolet (UV) resistance and DNA repair proficiency, by transfection with a human expression cDNA library, followed by selection to UV resistance. We now show that the transfected cDNAs can be rescued from cellular DNA of a secondary transformant by its in vitro amplification using expression-vector-specific oligodeoxyribonucleotides as primers in a polymerase chain reaction. The amplified cDNAs were cloned into a mammalian expression vector. Their transfection into XP cells identified a single cDNA which specifically complemented the UV sensitivity of a group-C-derived cell line to the same partial UV-resistance levels exhibited by the transformant from which the cDNAs were rescued.

Base Sequence↗
PubMed1990

Pitch interactions in the perception of isolated musical triads.

In previous work done in our laboratory, we have investigated the perceived pitch class of isolated musical triads. We have found that as the amount of musical training increased, listeners perceptions progress, from very confused percepts of pitch class, to analytic percepts corresponding to the pitch class of the highest note in the triad, and finally to synthetic percepts corresponding to the root note for the more harmonic triad types. In the present work, we used a pitch matching technique to determine the actual pitch, rather than merely the pitch class, perceived when listeners analytically "hear out" a particular note in a major triad. There was a strong tendency for the pitch of the analytically perceived note to be displaced by as much as 60 cents in the direction of the other notes in the triad. The magnitude of this effect decreased as musical training increased, and it was also affected by the relative salience of the individual triad notes. These results have implications for the mechanism of triad perception, and for claims regarding the harmonic equivalence of triad inversions.

Adolescent↗
PubMed1989

Ultraviolet light-resistant primary transfectants of xeroderma pigmentosum cells are also DNA repair-proficient.

In a previous work, an immortal xeroderma pigmentosum cell line belonging to complementation group C was complemented to a UV-resistant phenotype by transfection with a human cDNA clone library. We now report that the primary transformants selected for UV-resistance also acquired normal levels of DNA repair. This was assessed both by measurement of UV-induced [3H]thymidine incorporation and by equilibrium sedimentation analysis of repair-DNA synthesis. Therefore, the transduced DNA element which confers normal UV-resistance also corrects the excision repair defect of the xeroderma pigmentosum group C cell line.

Cell Line↗
PubMed1987

Half life and changes in the composition of a perfluorochemical emulsion within the vascular system of rats.

The decline of the concentration of perfluorochemicals (PFC) after a single injection of three different doses was studied in the circulation of rats. The doses used amounted to 4.4, 10 and 14 g/kg body weight of Fluosol-DA, an emulsion of 7 parts of perfluorodecalin (FDC) and 3 parts of perfluorotripropylamine (FTPA). This also allowed testing of the composition of the emulsion remaining in the circulation and of that found in the liver. After two days a decrease of the half life from 34.0 +/- 0.7 to 17.1 +/- 4.3 h was found within the circulation at the highest dose. At the same time a change in the composition of the emulsion in the blood stream occurred, favouring the fraction of FTPA. FTPA increased from 28.3 +/- 1.4 to 54.4 +/- 8.1% on the fourth day. Whereas in the cells of the liver PFC droplets may be broken up, freed from their surfactant layer and handled according to their individual components, for PFC in the blood stream an unchanged composition should be assumed. Both results, the decreasing half life and the change in composition of the circulating emulsion may best be explained by a shrinking and instability of the emulgator film, showing the necessity for development of a superior surfactant.

Animals↗
PubMed1987

Role of fluid replacement, increased oxygen availability by perfluorochemicals and enhanced RES function in the treatment of mesenteric occlusion shock.

UNLABELLED: Experiments were carried out on 183 rats to study the effect of a complex therapy for treatment of mesenteric shock. The superior mesenteric artery (SMA) was temporarily ligated for 90 min under ether anesthesia; this was followed by an analgesic treatment. After release of the ligated artery, fluid therapy was instituted by administering the equivalent of 7.5% of body weight of one of three different solutions: ringer lactate (RL), hydroxyethyl starch (HES) in RL, and perfluorochemicals (PFC, 4 g/kg b.wt. in RL with HES), the latter with the aim to improve the oxygen transport to the tissue. The same fluid therapy was carried out on rats pretreated with E. coli endotoxin. Endotoxin pretreatment was chosen to compensate the negative effect of PFC on the reticuloendothelial system (RES) as shown in previous studies. Survival time and survival rate were recorded as well as hematocrit values at different times before and after treatment. Experimental groups were: CONTROLS: (1) SMA occlusion without release; (2) 90-min occlusion without therapy. Treated animals: (3) RL therapy; (4) therapy with HES in RL; (5) therapy with PFC in RL and HES; (6), (7), and (8) identical therapies as Groups 3, 4, and 5, respectively, but with endotoxin pretreatment. Survival time increased to the same extent if HES or PFC were added to RL. There was a further increase both in survival times and rates with endotoxin pretreatment (Groups 6, 7, and 8 vs. Groups 3, 4, and 5). The highest survival time and rate were obtained in Group 8, which received PFC therapy with endotoxin pretreatment. There was a slight negative correlation between survival time and hematocrit values if all groups were considered together.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

[Distribution in the body and functional effects of fluorocarbons used as oxygen carriers].

After the infusion of perfluorochemicals (PFC) given as artificial blood gas carriers a temporary storage of the inert substances in tissues of the organism occurs. The time course of this effect was investigated in longitudinal studies in the rat and compared with changes of different organ functions, expressed as changes in the levels of serum enzymes, in the elimination of indocyanine green and in the duration of pentobarbital sleeping time which are dependent on the excretory and detoxifying functions of the liver. The intensity of the elimination of colloidal carbon was used as a measure of the activity of the reticulo endothelial system. Observation of the time course of these functional tests in comparison with the storage of PFC and changes in organ weight of liver and spleen showed that diminutions in function had a distinctly shorter duration than PFC storage, whereas the longest lasting effects were seen in organ weight increase is regarded as a compensatory effect that is associated without functional loss at the maximum of its appearance.

Animals↗
PubMed1985

Human papillomavirus type 16 related DNA in an anaplastic carcinoma of the lung.

Twenty-four biopsy specimens from various histologic types of human carcinomas in the lung were analyzed for the presence of human papillomavirus (HPV) DNA. DNA from the individual specimens was tested for the presence of homologous sequences to HPV genotypes 1, 2, 4, 8, 9, 10, 11, 13, 16 and 18. One anaplastic carcinoma in the lung contained multiple copies of DNA hybridizing under stringent conditions to HPV 16 DNA. The latter DNA has been found to be frequently associated with human genital cancer (cervical, penile, and vulval cancer) and genital Bowen's disease. The HPV 16 positive lung tumor originated from a 61-year-old female patient who underwent hysterectomy due to cervical cancer 9 years earlier.

Base Sequence↗
PubMed1985

[Demonstration of antibodies against tumor-associated antigens in the serum patients with bronchogenic carcinoma using anticomplement immunofluorescence on xenotransplants of human tumors].

209 sera of tumor-bearing patients and 133 control sera were tested by anti-complement immunofluorescence (ACIF) on 2 xenotransplants of human bronchogenic cancer and on 2 xenotransplants of rectum carcinoma passaged in nu/nu mice. Testing of sera from patients with bronchogenic carcinoma resulted in a positive reaction with the xenotransplants of bronchogenic cancer in 48.5 to 58.5%, and sera of patients with digestive tract cancer in 6.6 to 16.1%. On xenotransplants of rectum carcinoma 73.2 to 78.1% of the sera from patients with bronchogenic carcinomas and 22.6 to 29.1% of the sera of patients with digestive tract cancer reacted positively. Control sera were positive dependent on the xenotransplants in 2.0 to 12.5%. These results indicate that there are antibodies in the sera of tumor-bearing patients against one or more non organ specific tumor-associated antigen(s) occurring in an elevated concentration in carcinomas of the digestive tract than in bronchogenic carcinomas. After absorption of the sera with homogenates of bronchogenic carcinoma and liver metastases of colon carcinoma the reaction was inhibited in the ACIF, reaching control values.

Adenocarcinoma↗
PubMed1984

Molecular characteristics of two lung carcinoma cell-line associated membrane antigens.

The molecular characteristics of the antigens detected by the moab BW 181/26 and BW 166/6 are described. The 55 KD molecule defined by BW 181/26 is strongly attached to the plasma membrane and is not secreted, whereas the 140 KD (96 KD) and 120 KD (61 KD) molecules recognized by BW 166/6 are loosely associated to the cell membrane and secreted into the tissue culture medium. The last two antigens might be used as markers for the early detection of certain lung carcinomas, whereas the 55 KD membrane associated antigen could be a target for immunotoxins used in immunotherapy of cancer.

Animals↗
PubMed1984

The use of cationic polyelectrolytes in the preparation of cell monolayers for automated cell scanning and diagnostic cytopathology.

The introduction of cationic polyelectrolytes as cellular adherents has significantly advanced the preparation of cervical scrape specimens for automated cell scanning and has also provided an efficient technique for the preparation of cell monolayers of other cytologic specimens, e.g., breast cyst fluids, urines and serous effusions, for diagnostic cytopathology. Variable thickness of cell preparation and cell overlap have both been resolved by laying cells onto glass slides coated with the cationic polyelectrolyte poly-L-lysine. We have determined the optimal conditions for pH, molecular weight, concentration and temperature for the application of poly-L-lysine as a cell-to-slide adhesive.

Cell Adhesion↗
PubMed1983

The recognition of human bronchogenic carcinomas.

Xenotransplants of human carcinomas were tested for consistency of the analytical data of tumor markers over several passages in nude mice and nude rats. The binding properties of antibodies against tumor-associated antigens present in sera from tumor-bearing patients were tested with aid of the anticomplement immunofluorescence. The best binding capacity was found when sera from patients with bronchogenic carcinomas reacted on xenotransplants of the digestive tract (70%). Because of the low values for controls as well as for inflammatory diseases, this test may be applicable in the early recognition of lung cancer.

Animals↗
PubMed1981

Modern autotransfusion. Experience with a washed red cell processing technique.

The technique of intraoperative autotransfusion utilizing the Haemonetics Cell Saver is described. This device separates and washes red blood cells removed from the surgical field. Advantages of this unit over others are (1) no systemic anticoagulation is required, (2) circulatory fibrin debris is removed, (3) plasma hemoglobin is removed, and (4) any circulating anticoagulant is removed. Experience with 136 consecutive cases. 101 elective and 35 emergency, is reported. The only complication was coagulopathy, which occurred in 5.1 percent of the cases. It is easily treated with blood component therapy and occurs in those patients in whom greater then 3,500 cm3 of blood is autotransfused. The Cell Saver has proven an important adjunct in surgical patients in whom greater than 1,000 cm3 of blood will be lost, as well as in emergency patients. It provides an efficient, economical and safe method to autotransfuse blood.

Adult↗