Vaclav Klement

Treatment of cervical carcinoma employing a template for transperineal interstitial Ir192 brachytherapy

The development of a template technique at this institution for transperineal interstitial-intracavitary brachytherapy employing Ir192 wire has previously been reported. In this paper we report the results of radiation treatment of 84 women with fresh, primary squamous carcinoma of the cervix admitted to the Los Angeles County--University of Southern California Medical Center from April, 1975 to September, 1979 who received at least one transperineal template implant as part of their initial treatment. The 75 evaluable patients were followed 3 to 60 months, with a median of 17 months. Recurrence rates in the pelvic treatment field by clinical (FIGO) stage grouping were 35.7% (5/14) Stage IB;0% (0/8) Stage IIA; 20% (5/25) Stage IIB; 46.2% (12/26) Stage III; and 0% (0/2) Stage IVA. The overall failure rate within the treatment field was 29.3% (22/75). The non-tumor associated rectovaginal and vesicovaginal fistula rate was 14.3% (2/14) in Stage IB; 0% (0/8) in Stage IIA; 16.0% (4/25) in Stage IIB; 15.4% (4/26) in Stage III; and 0% (0/2) in Stage IVA. The non-tumor associated fistula rate for all stages was 13.3% (10/75). Severe or grade III nonfistulous, delayed adverse effects (proctosigmoiditis, cystitis, vault necrosis) occurred in an additional 6 patients. Thus, 21.3% (16/75) of all evaluable patients experienced severe adverse radiation effects during the follow-up period. Pre-radiation staging laparotomy was performed on 31 patients. It had no obvious effect on the pattern or rate of radiation complications. The role of the interstitial-intracavitary template in the treatment of primary cervical carcinoma is discussed.

Clonal heterogeneity of wild mouse leukemia viruses: Host range and antigenicity

Abstract Type C RNA virus from feral mice ( Mus musculus ) was found to consist of two distinct virus populations: mouse-tropic, positive in the XC test, and amphotropic, with broad host range and negative in the XC test. Serum neutralization revealed antigenic differences among mouse-tropic and amphotropic clonal isolates and between these viruses and standard laboratory leukemia virus strains.

Biologically selected recombinants between feline leukemia virus (FeLV) subgroup A and an endogenous FeLV element

In efforts to elucidate the proximal leukemogens that might be produced during a feline leukemia virus (FeLV) infection of cats, homologous recombinations between molecularly cloned exogenous and endogenous FeLV proviruses of known sequences were examined in cell cultures in vitro. A plasmid containing an infectious member of the most commonly occurring FeLV subgroup (FeLV subgroup A or FeLV-A) was coexpressed with noninfectious constructs containing the envelope (env) gene of an endogenously inherited FeLV-like feline genomic element in transfected feline fibroblasts. The viruses generated were selected for their ability to propagate in human cells which are resistant to infection by the parental ecotropic FeLV-A or the noninfectious endogenous constructs. An analysis of the recombinants thus derived identified a limited number of sites in the env gene which were preferentially utilized in the generation of recombinant FeLVs under the selection conditions used. These sites were clustered in the surface glycoprotein (SU) moiety of the env gene, and it appeared that most, but not all, of the SU gene product of FeLV-A, beginning from the N-terminus, can be replaced by sequences from an endogenous element, still allowing the virus to be biologically viable. In fact, these substitutions in the env gene expanded infectivity of the parental FeLV-A from ecotropic to polytropic cell tropism. Additionally, substitutions in the SU region yielded many recombinants in which a primary neutralizing pentapeptide epitope of FeLV-A was altered because of its variance in the endogenous element. In several of the recombinants, this sequence was also found to be frequently mutated. Consistent with the changes identified in this antibody-binding domain, the recombinant viruses were only weakly inhibited by a monoclonal antibody directed against this epitope, while FeLV-A was highly sensitive to neutralization.

Type C Virus Expression in Lymphoma-Paralysis-Prone Wild Mice

Abstract Wild mice trapped near Lake Casitas (LC) in southern California showed a high prevalence of infectious type C virus in the liver, spleen, and thymus within the first few weeks of life. By young adulthood about 80% of LC mice (including their genital tissues) were infected. Virus isolates from these mice cause lymphoma and lower limb paralysis under both natural and experimental conditions. Mice destined to develop paralysis showed higher levels of serum gs antigen early in life, whereas mice destined to develop lymphoma or remain free of these diseases could not be distinguished by this test. The individual variation in virus expression suggested that differences in virus type or in the immune or other host defense mechanisms greatly influenced susceptibility or resistance to indigenous type C virus-caused disease in LC wild mice.

Reversion of Kirsten sarcoma virus transformed human cells: elimination of the sarcoma virus nucleotide sequences.

The virus-specific nucleotide sequences in the RNA and DNA of a Kirsten mouse sarcoma virus (Ki-MSV)-transformed non-producer human osteosarcoma cell clone and two subclones of these cells that reverted to a normal phenotype have been analysed by hybridization of sarcoma virus-specific complementary DNA (cDNA) to cellular RNA or DNA. Whereas the transformed clone had acquired de novo Ki-MSV sequences in the RNA and DNA of the cells, both the revertant cell lines seemed to have lost most or all of this information from the cellular nucleic acids. The DNA from the revertant cells lacked the sequences represented either in the Ki-MSV-specific cDNA or in the total cDNA of the leukaemia-sarcoma virus complex. Thus, the reversion of the virus-transformed human cells to normal morphology is associated with the loss of most or all of the proviral sequences from the cellular DNA.

Endogenous type C RNA virus of mink (Mustela vison).

Abstract A type C RNA virus was isolated from mink lung cell line (American Type Culture Collection No. CCL 64) which had been cocultivated with 5-bromodeoxyuridine (BUDR)-treated mouse spleen cells. The virus has type C RNA virus morphology as demonstrated by electron microscopy. The complement fixation and immunofluorescent tests performed with mouse anti-p30 antisera show a distinctive difference between mink and mouse type C viruses. Complement fixation tests also indicate that mink type C virus is antigenically different from rat, feline leukemia, feline endogenous (RD-114), baboon, and woolly monkey type C viruses. The virus propagates in cells of mouse, rat, cat, sheep, dog, and human origin, but not in bovine (MDBK) or simian (BSC-1) cells. The infection of rabbit (SIRC) cells and cells of virus origin (mink lung) was followed by delayed and low-titer polymerase release in tissue culture media. The virus sediments in sucrose density gradients as a broad band of densities, 1.13–1.17 g/ml, and contains 70 and 4S RNA. The protein profile is similar to that observed in other mammalian type C viruses. The DNA complementary to the poly(A)-containing virion RNA hybridized to a high degree (72%) with the RNA from virus-producing mink lung cells but not with the RNA from mouse cell lines or uninfected mink lung cell line. The nucleotide sequences homologous to mink viral cDNA were found in mink cell DNA from both virus-producing and nonproducing cells, but not in the DNA of mouse, rat, or feline origin. The virus here described therefore represents an endogenous mink type C virus.

Characterization of a defective pseudotype particle of Kirsten sarcoma virus

Abstract A cell line has been isolated that produces a defective pseudotype particle of Kirsten sarcoma virus without detectable infectious helper virus. Normal rat kidney cells were infected at low multiplicity with a virus stock obtained by the rescue of Kirsten sarcoma virus with woolly monkey leukemia virus. The individual transformed cell foci which resulted were propagated. One was found to produce noninfectious oncovirus particles containing high reverse transcriptase activity. These defective particles contained an active sarcoma genome but no detectable helper virus genome as cells fused to the particles became transformed but did not show evidence of helper woolly monkey leukemia virus expression. Nevertheless, the rat kidney cells producing the defective particles contained the complete woolly monkey leukemia virus genome; after prolonged culture, infectious woolly monkey leukemia viruses were released and rapidly spread through the culture. The defect of the noninfectious particle could be attributed to the absence of the viral envelope glycoprotein. Helper virus env gene products were not detected in cells producing the defective particle, nor did these cells exhibit interference to superinfection by woolly monkey leukemia virus. The protein composition of the defective particle was unusual. Major proteins were a woolly monkey virus p28 and a novel 55,000-dalton protein of rodent origin. The 55,000-dalton protein was not immunologically related to the known rodent type-C virus gag or env gene products; nevertheless, it was immunoprecipitated by several anti-murine leukemia virus sera, suggesting that a related protein is commonly present in preparations of purified mouse type-C viruses.