Differential oncogene amplification in tumor cells from a patient treated with cisplatin and 5-fluorouracil

Peritoneal cells were derived from a patient (PK) with adenocarcinoma of the colon during the course of cisplatin/5-fluorouracil (5-FUra) treatment. Resistance to cisplatin and 5-FUra, characterized by a lack of response to chemotherapy and continued growth of the tumor, was concomitantly associated with a 2-4-fold increase in DNA copy number for dTMP synthase and dihydrofolate reductase. There was a corresponding amplification in DNA copy number of the c-myc (2X), H-ras (4X), and c-fos (15X) oncogenes. Cytogenetic studies revealed an iso (13q) chromosome, but failed to show any double minutes or homogeneously staining regions. In addition, drug-resistant tumor cells from PK and another patient (HG) displayed enhanced expression of dTMP synthase, c-fos and DNA polymerase beta when compared to normal colon tissue and the HCT8 human colon carcinoma cell line. These results suggest that elevated oncogene DNA and gene expression may be involved in the development of cisplatin resistance.

Expression of chimeric human transferrin genes in transfected human tumor cell lines

The iron-binding plasma protein transferrin (TF) is essential for supplying iron to cells and the prevention of iron toxicity. Our laboratory has cloned and characterized the human TF gene. Comparison of promoter regions of TF genes from human, chicken, and mouse reveals a strong nucleotide sequence conservation. This study demonstrates that 5' flanking regions of the TF gene are sufficient for directing expression of a heterologous gene in transgenic mice and transfected cells. For cell-specific expression, more than 150 base pairs appear to be required.

Isolation, purification and characterization of infectious hypodermal and hematopoietic necrosis virus (IHHNV) from penaeidshrimp

A protocol was developed for the isolation and purification of the infectious hypodermal and hematopoietic necrosis virus (IHHNV) of penaeid shrimps. Cesium chloride-banded virus obtained from three sources of infected shrimps was found to have a buoyant density of 1.33 g/cm3. Also, electron microscopical studies employing negative stain revealed isometric particles having a size of 19 +/- 1 nm. Colorimetric analysis of its nucleic acid type indicated that these particles contain only RNA.

[CT investigation of renal cystic masses]

This report presented 61 cases of renal cystic masses including renal parenchymal cyst 57 cases; parapelvic cyst 2; cystic hypernephroma 1 and calyceal diverticulum 1 case. All were confirmed by CT guided puncture and aspiration. The CT features of various renal cysts. complications and some special manifestations as well as differential diagnosis were discussed. Pertinent analysis of the CT features are necessary for correct diagnosis and proper management.

Effects of long terminal repeat mutations on human immunodeficiency virus type 1 replication

The effects of deletions within three functional regions of the long terminal repeat of human immunodeficiency virus type 1 upon the ability of the long terminal repeat to direct production of the chloramphenicol acetyltransferase gene product and upon the ability of viruses that carry the mutations to replicate in human cell lines was investigated. The results show that the enhancer and TATAA sequences were required for efficient virus replication. Deletion of the negative regulatory element (NRE) yielded a virus that replicated more rapidly than did an otherwise isogeneic NRE-positive virus. The suppressive effect of the NRE did not depend upon the negative regulatory gene (nef), as both NRE-positive and NRE-negative viruses were defective for nef. We conclude that factors specified by the cell interact with the NRE sequences to retard human immunodeficiency virus type 1 replication.

The therapeutic efficacy of the choleretic mixture against the infantile hepatitis syndrome

Observation was made on a control study of the therapeutic efficacy of the choleretic mixture in treating 35 cases of infantile hepatitis syndrome in comparison with that of the choleretic decoction. The ages, duration of the disease, severity of icterus and serum bilirubin level in both groups were comparable. The results showed that there was no significant difference in therapeutic efficacy between the two groups, however, the resolving time of skin icterus was faster in the choleretic mixture group than in the choleretic decoction group. The choleretic mixture was convenient, easy to store, and acceptable to infants for its small dosage, and no side effects, therefore, a desirable drug against infantile hepatitis syndrome.

The vascular microanatomy of skin territory of posterior forearm and its clinical application

We have undertaken a microanatomical study of a new donor site--the posterior forearm territory--on 43 cadaver arms. Two axial arteries were found, and both the fasciocutaneous flap and the fascial flap could be elevated with the two arteries on the posterior forearm. The posterior forearm flap was transferred to the hand to repair deformities of the wrist, the first web space, the dorsal hand, and the metacarpophalangeal joints in eight cases. The result was very satisfactory. The posterior forearm flap is near the hand, easy to perform, and reliable. It is a one-stage operation and does not sacrifice a main artery. In this article we demonstrate our own ideas about flap extension, which is valuable for clinical application.

Detection of drug resistance in human tumors by in vitro enzymatic amplification

Both acquired and natural resistance to chemotherapy agents have proved problematic in the treatment of neoplasia. Thymidylate synthase, which catalyzes the synthesis of thymidine precursors, has been shown to be amplified in response to a variety of chemotherapeutic agents. The detection of such amplification could prove beneficial in the development of alternative clinical protocols. In this study we report the use of existing enzymatic amplification methods in order to detect incipient amplification of the thymidylate synthase gene upon resistance to cisplatin. The assay utilizes a modification of the polymerase chain reaction in which a sequence of the thymidylate synthase gene is amplified including two flanking oligonucleotides acting as primers for DNA synthesis. This method exhibits greater sensitivity than conventional nucleic acid detection methods and requires less than 100 ng of total RNA from patient tumors and no in vitro culturing of patient cells.

Biochemical and molecular properties of cisplatin-resistant A2780 cells grown in folinic acid

In this study, A2780 human ovarian carcinoma cells were grown in folinic acid in contrast to folic acid, and the molecular and biochemical properties of cisplatin-resistant A2780 cells were analyzed for changes in the dTMP synthase cycle. At concentrations of folinic acid that were optimal for cell growth (10(-8) M), the ED50 for cisplatin was 2.5 and 43 microM in the A2780S and A2780DDP cells, respectively. Resistance to cisplatin was associated with a 2-fold cross-resistance to 5-fluorodeoxyuridine and 5-fluorouracil as well as a 3-fold increase in both dTMP synthase activity and mRNA. The ED50 for methotrexate was similar in both A2780S and A2780DDP cells (1.2 microM). When both the A2780S and A2780DDP cells were grown in folinic acid, there was no significant difference in the level of dihydrofolate reductase activity. This data would suggest that cisplatin resistance is associated with changes in folate metabolism.

Mechanisms of cross-resistance to methotrexate and 5-fluorouracil in an A2780 human ovarian carcinoma cell subline resistant to cisplatin

Some properties of the human ovarian carcinoma line A2780 and a subline three times more resistant than the parent line to cisplatin are compared in this report. The rates of uptake and release of cisplatin were similar in the two cell lines. Resistance to cisplatin was associated with: (a) cross-resistance to 5-fluorouracil and methotrexate; (b) a 2.5-fold increase in thymidylate synthase, as measured by both enzyme activity and the capacity to complex 5-fluorodeoxyuridylate; and (c) an increase in the intracellular pools of 5,10-methylenetetrahydrofolate and tetrahydrofolate. These data suggest that cross-resistance to 5-fluorouracil and methotrexate in A2780 cells may be a consequence of increases in their respective target enzymes.

Mechanisms for cisplatin-FUra synergism and cisplatin resistance in human ovarian carcinoma cells both in vitro and in vivo

Cisplatin and FUra act synergisticly in human carcinomas. An increase in the availability of reduced folates necessary for tight binding of FdUMP to thymidylate synthase (TS) contributes to the enhanced cytotoxicity of this drug combination. The human ovarian A2780 cell line made three-fold resistant to cisplatin has been shown to have a three-fold elevation of m-RNA for dihydrofolate reductase (DHFR) and TS. However, this increase did not result from an amplification of the genes for these two enzymes. In contrast, ovarian carcinoma cells from patients who failed treatment with cisplatin and FUra have been shown to have both enhanced gene expression and increased gene copy number for DHFR and TS.

Successful replantation in ten-digit complete amputations

The authors report a case of successful replantation of all fingers in a ten-finger complete amputation. Among the factors responsible for the successful outcome were an adequate number of microsurgically-trained resident surgeons and staff, good organization and supervision by senior staff, emphasis on precision and perseverance in the operative procedures, and postoperative management. Follow-up is 15 months, and the patient now has a pair of functionally and cosmetically good hands.

Use of capillary blood for the evaluation of iron status

The accuracy and precision of measurements of iron status made on the capillary blood from a single 75 X 1-mm microhematocrit tube were evaluated in 301 normal volunteers. After recording the hematocrit value, a hematofluorometer was used to assay erythrocyte protoporphyrin directly on the packed red cell fraction. Values in the low normal range were 50-100% higher than assays by an extraction technique in simultaneously collected venous blood. However, measurements in the iron deficient range were only 12% greater. Plasma ferritin concentration was determined by using an enzyme-linked immunoassay on 10-microliters plasma retrieved after measuring the hematocrit. Capillary values were approximately 7% higher than venous concentrations, the proportional difference being consistent throughout the measured range. When the individual measurements were combined to calculate the iron storage status of each individual, the frequency distribution of iron stores in 141 female volunteers between 18 and 36 years of age was approximately Gaussian and paralleled that calculated for women aged 18-44 years in NHANES II. These studies demonstrate that iron status can be determined accurately from the measurement of hematocrit, erythrocyte protoporphyrin, and ferritin on a single microhematocrit tube of capillary blood.

Biochemical basis for cisplatin and 5-fluorouracil synergism in human ovarian carcinoma cells

The human ovarian cell line A2780 was exposed to either cisplatin (10 microM) or 5-fluorouracil (5FUra) (5 microM) for 1 hr. Cytotoxicity was less than 14% with either agent alone. Cisplatin (10 microM) and 5FUra (5 microM) in combination for 1 hr caused a 76% reduction in cell growth. Thymidine (dThd, 10 microM), if given concomitantly with the combination of cisplatin and 5FUra, completely protected the tumor cells. A 30-min exposure to cisplatin increased the intracellular pools of 5,10-methylenetetrahydrofolate and tetrahydrofolate 2.5-fold. The capacity of intact cells to form 5-fluorodeoxyuridylate (FdUMP)-thymidylate (dTMP) synthase complex when incubated with fluorodeoxyuridine (FdUrd) was enhanced 2.5-fold when the cells were pretreated with cisplatin. These experiments demonstrate that cisplatin can increase the availability of the reduced folate necessary for tight binding of FdUMP to dTMP synthase, thus enhancing the cytotoxicity of the cisplatin and 5FUra combination.

Biomembranes as models for polymer surfaces. IV. ESCA analyses of a phosphorylcholine surface covalently bound to hydroxylated substrates

Using a simple chemical process, phosphorylcholine has been deposited covalently on the surface of a variety of hydroxylated polymers as a stable, monomolecular coating. Our goal was to obtain new biomaterials which, due to the chemical similarity of the modified interfaces to the phospholipid head groups present on the extracellular surfaces of blood cell membranes, should exhibit enhanced haemo- and biocompatibility. Our previous analyses by chemical and spectrophotometric methods indicated that sufficient quantities of phosphorylcholine were deposited on glass and silica surfaces to result in appreciable modification of their interfacial properties. In the present study, we have examined a series of modified hydroxylated substrates by ESCA and demonstrate specific chemical modifications on the molecular surfaces of polymeric substrates.

Properties of amino acid transport systems in K562 cells sensitive and resistant to cis-diamminedichloroplatinum(II)

When K562 cells were made resistant to cisplatin their neutral amino acid transport systems changed. K562 cells cloned in cisplatin developed a 6.7-fold resistance to the drug. The generation times for K562 cells sensitive (S) and resistant (DDP) to cisplatin were similar. The initial uptake and rapid efflux of cisplatin were similar in both cell lines. However, they differed in their sodium dependent neutral amino acid transport properties. In K562S cells the sodium-dependent uptake for methylaminoisobutyric acid was significantly inhibited by threonine (Ki = 10.3 mM), but in K562DDP the uptake of neutral amino acids was significantly lower, and methylaminoisobutyric acid uptake was minimally inhibited by threonine. When K562DDP cells were grown in the absence of cisplatin for 8 weeks, their amino acid transport properties reverted to those of K562S cells. In K562 cells, changes in plasma membrane essential amino acid transport systems were concomitant to both the development of resistance and the redevelopment of sensitivity to cisplatin. Therefore, human malignant cell sensitivity and resistance to cisplatin may be related to membrane nutrient transport systems.