Comparison of ritonavir plus saquinavir- and nelfinavir plus saquinavir-containing regimens as salvage therapy in children with human immunodeficiency type 1 infection

BACKGROUND

In this retrospective study we compared the antiretroviral effect of regimens consisting of simultaneous administration of two protease inhibitors (PI) with at least one nucleoside reverse transcriptase inhibitor on plasma viral load (VL) and CD4 cell count in HIV-infected children intensively pretreated with nucleoside reverse transcriptase inhibitors and PIs.

METHODS

Eleven HIV-infected children were changed to antiretroviral combination regimens including two PIs and followed for a median time of 24 weeks. Group A comprised six patients who were given ritonavir + saquinavir (SQV) and Group B consists of five patients who were changed to nelfinavir + SQV. Patients were treated with these combinations with 2 PIs because of treatment failure (increasing viral load) of prior PI therapy or clinical signs of disease progression.

OUTCOME MEASURES

Serial determinations of plasma viral load (Amplicor, Roche) and CD4 cells were performed every 4 to 8 weeks. The detection limit of the Amplicor-reverse transcriptase-PCR assay was 50 copies/ml (1.7 log10).

RESULTS

In Group A the median VL reduction was 1.1 log10 after 3 months and 1.4 log10 after 6 months. In Group B median VL decreased 0.1 and 0.2 log10 after 3 and 6 months. In both groups during the study period none of the patients reached undetectable VL. The relative changes of CD4 cells above baseline in Group A showed a median increase of 7% after 3 months and 23% after 6 months. In Group B after 3 months CD4 cells did not increase, and after 6 months the median relative increase was only 7%. Both combination therapies were well tolerated, not necessitating any drug interruption during study period.

CONCLUSIONS

In children with intensive prior antiretroviral treatment, a salvage therapy including two PIs demonstrated antiretroviral efficacy in some patients. In this study the reduction of the VL as well as the increase of CD4 cells was more pronounced with ritonavir + SQV than with nelfinavir + SQV. With both combinations complete suppression of HIV replication was not achieved. Therefore the long term effect of these combinations may be limited by the emergence of resistant HIV strains.

[Prolonged peridural analgesia (PDA) for postoperative pain therapy after major urologic interventions. Experiences with 172 adult patients]

The benefits of epidural analgesia are well known, but it is not well understood which types of urologic surgery benefit most from epidural analgesia. In this study, the effects and side effects of prolonged epidural analgesia are prospectively examined and analysed on 172 adult patients in three different operation groups. An epidural infusion of local anaesthetic combined with an opioid and adrenaline was given for a period of 5-7 days. There was no difference between the groups with respect to the effectiveness of the analgesia and patients' perception of the treatment. Mobilization differed, as expected, between the groups, however even after the most major surgery (e. g. cystectomy with bladder substitution), mobilization was impressively unproblematic. Retarded return of regular intestinal function after the transperitoneal operation and partly after lumbotomy compared with the extraperitoneal operation depended on which operation was performed and the amount of analgesia given. The side effects such as sedation, nausea and pruritus were conditional partly on the opiate and partly on the intervention. Up to 11 % showed slight muscular weakness of the lower limbs as a specific side effect of the local anaesthetic.

COMPLICATIONS

One patient died of cerebral hypoxia due to an initially undetected subdural catheter placement complicated by severe pre-existent carotid stenosis. In four patients, the epidural analgesia had to be stopped because of catheter migration. There was no clinical evidence of hematoma, abscess or permanent neurological damage. Epidural analgesia works well in terms of analgesia, mobilization and patient satisfaction, bearing in mind the potential side effects and complications. It can be recommended for lumbotomy and long transperitoneal operations however not for extraperitoneal interventions in the lower abdomen such as radical prostatectomy.

Skeletal effects of zinc deficiency in growing rats

There is ample evidence that zinc plays an important role in bone metabolism and zinc deficiency has been implicated as a risk factor in the development of osteoporosis. It was the aim of the present study to investigate the skeletal effects of alimentary zinc deficiency in growing rats using quantitative bone histomorphometry. Twenty-four male Sprague Dawley rats with a mean initial body weight of 101 +/- 2 g were allocated in two groups of 12 rats each and had free access to a semi-synthetic, casein-based, zinc-deficient diet (0.76 mg zinc/kg) or to the same diet supplemented with 60 mg zinc per kg. All rats were sacrificed 42 days after the start of the experiment and the right distal femur was removed for bone histomorphometry. Relative to controls (+Zn), the zinc-deficient rats (-Zn) had a significantly lower body weight and about an 80% reduction in plasma and femur zinc concentration. The histomorphometric evaluation of the distal femoral metaphysis showed that zinc deficiency led to a 45% reduction (p < 0.01) in cancellous bone mass and to a deterioration of trabecular bone architecture, with fewer and thinner trabeculae. The osteopenia in -Zn rats was accompanied by significant reductions in osteoid perimeter (-31%, p < 0.05), osteoblast perimeter (-30%, p < 0.05), and osteoclast number (-38%, p < 0.01) relative to +Zn controls. We conclude that zinc deficiency induced low turnover osteopenia in femoral cancellous bone of growing rats. These results support the hypothesis that zinc deficiency during growth may impair the accumulation of maximal bone mass in humans; additionally, they suggest that zinc deficiency may play a role as a risk factor in the pathogenesis of osteoporosis.

Downregulation of endothelin B receptor in human melanoma cell lines parallel to differentiation genes

Normal human melanocytes have been shown to respond to the signal peptide endothelin by increased proliferation and melanin formation. Contradictory findings, however, have been reported about which of the two endothelin receptors (EDNRA or EDNRB) is expressed in normal melanocytes and melanoma cells. Moreover it was not clear whether malignant cells differ from their normal precursors in this respect. Screening a melanocyte cDNA library for genes downregulated in melanomas identified clones specific for EDNRB. Northern blots proved that the corresponding mRNA is generally expressed in cultures of human cutaneous melanocytes and congenital melanocytic nevus cells. In 16 of 17 melanoma cell lines, however, the expression of EDNRB mRNA was strongly downregulated. EDNRA was only weakly expressed and detectable by northern blotting in 12 of 17 cultures of benign melanocytic cells and four of 17 melanoma cell lines. Nested reverse transcriptase-polymerase chain reaction proved several melanoma cell lines to be completely negative for EDNRA expression. Gene deletion as the cause of missing endothelin receptor expression was ruled out by genomic Southern blots. Receptor binding assays confirmed RNA data revealing 1.6 x 105 endothelin-1 binding sites per cell for a melanocyte culture and between 8.7 x 104 and 400 sites per cell for melanoma cell lines. Expression of pigmentation genes coding for tyrosinase, TRP-1 and TRP-2 correlated positively with that of EDNRB but negatively with EDNRA expression. EDNRB but not EDNRA expression is therefore typical for melanocytic cells, and downregulation of EDNRB seems to be an important characteristic of melanoma cells possibly related to malignancy or apoptosis.

Coreceptor requirements of primary HIV type 1 group O isolates from Cameroon

HIV-1 group O has its epicenter in Cameroon and neighboring countries and is responsible for 3 to 5% of all HIV infections in this region. It is believed that HIV-1 group O was introduced into the human population by a separate cross-species transmission, occurring independently of the HIV-1 (group M and group N) and HIV-2 transmissions. We have studied the coreceptor requirements of 12 primary HIV-1 O-type isolates from individuals with different clinical symptoms. Only 2 of these 12 viruses showed a syncytium-inducing phenotype after infection of primary peripheral blood mononuclear cells (PBMCs) and were infectious for the T cell line C8166. These isolates used CXCR4 as a coreceptor for entry, whereas the remaining isolates used only CCR5 efficiently. One isolate was able to use BOB and CCR8 as coreceptors in addition to CXCR4. All group O isolates tested were efficiently inhibited by SDF-1 or RANTES, the natural ligands of CXCR4 and CCR5, respectively. These results indicate that CXCR4 and CCR5 are the principal coreceptors for HIV-1 O-type viruses. Most of the HIV-1 group O isolates studied were derived from patients at later stages of the disease. Although HIV-1 group O and group M infections do not differ in their pathogenesis, the studied isolates did not evolve to use a broad range of coreceptors as described for HIV-1 group M and HIV-2.

Desensitization of melanoma cells to autocrine TGF-beta isoforms

Previous studies have suggested that transforming growth factor-beta 1 (TGF-beta1) acts as an autocrine growth inhibitor on normal human melanocytes, while melanoma cells may not respond to this stimulus. The role of other TGF-beta isoforms such as TGF-beta2 and TGF-beta3 remained less well characterized. In the present study, the mRNA and protein levels of all three isoforms of TGF-beta were analyzed in a panel of human melanoma cell lines and in cultures of normal human melanocytes in vitro. Northern analysis showed that the degree of TGF-beta1, -beta2, -beta3 mRNA expression varied considerably in melanoma cells, whereas TGF-beta expression was very low in melanocytes. In melanoma cells, secreted amounts of TGF-beta1 and TGF-beta3 were found increased in comparison to normal melanocytes: 615 pg/ml vs. 118 pg/ml and 193 pg/ml vs. 30 pg/ml (mean values). In addition, low levels of TGF-beta2 were detected (mean value: 28 pg/ml). Although TGF-beta secretion increased, the proliferation of melanoma cells was found to be only moderately inhibited by TGF-beta isoforms, in contrast to its strong antiproliferative effect on normal human melanocytes: - 15%, -11%, and -18% vs. -52%, -46%, and -50% average inhibition at 0.5 ng/ml TGF-beta1, -beta2, and -beta3, respectively. The different efficacy of TGF-beta on melanocyte and melanoma cells was highly significant (P<0.0001); in addition, TGF-beta-dependent growth inhibition of melanoma cells from primary tumors vs. cells from metastases showed a trend for further decreased response for the metastatic populations (P< or = 0.075). Measurements of DNA synthesis revealed even more pronounced differences between melanocytes (-86%, -78%, and -80% inhibition, respectively, for TGF-beta1, -beta2, and -beta3) and melanoma cells (no inhibition). Our data show loss of responsiveness of melanoma cells to the growth-inhibitory function of TGF-beta isoforms but not of melanocytes. Although melanoma cells are not growth-inhibited by all three TGF-beta isoforms, they secrete significantly higher levels of TGF-beta, as compared to melanocytes. The reduced response indicates their escape from TGF-beta surveillance with ongoing tumor progression.

HIV type 1 diversity and the reliability of the heteroduplex mobility assay

We investigated HIV-1 diversity by means of heteroduplex mobility assay (HMA) genotyping. We studied 199 samples from patients originating from 26 countries and living in France. The HMA successfully genotyped 182 (91%) of these samples, as follows: 77 (42%) subtype A, 57 (31%) subtype B, 5 (3%) subtype C, 5 (3%) subtype D, 8 (4%) subtype E, 22 (12%) subtype F, 5 (3%) subtype G, and 3 (2%) subtype H. We were not able to genotype 12 samples by means of the HMA. These latter strains were sequenced, and phylogenetic analyses revealed that they were highly divergent subtype A-, D-, or G-related strains. Eight (of 12) subtype D strains were indeterminate by HMA, owing to the broad intrasubtype diversity, suggesting that new reference subtype D plasmids are required, as previously proposed. Thirty-seven strains belonging to the different subtypes were sequenced, and the results showed perfect concordance with the HMA results. Interlaboratory quality controls confirmed the reliability of the HMA for HIV-1 subtyping, despite the extensive viral variability. However, plasmid selection must be continuously revised to cover viral diversification.

Human melanoma cell lines show little relationship between expression of pigmentation genes and pigmentary behaviour in vitro

Several laboratories are pursuing the question of whether the expression of pigment genes can be used as a useful marker for tumour progression. However, many melanoma tumours are amelanotic in vivo. The purpose of this study was to examine the relationship between the expression of tyrosinase-related genes [tyrosinase, tyrosinase-related protein-1 (TRP-1) and tyrosinase-related protein-2 (TRP-2)] and pigmentation of melanoma cells. Fourteen cutaneous melanoma cell lines were examined for visible pigment, melanin content, and dopa oxidase activity and findings were related to the previously determined expression of the three tyrosinase-related genes in these cells in culture. Four of the cell lines were also stimulated with alpha-MSH, isobutylmethylxanthine, and forskolin to examine the relationship between induced pigmentation and upregulation of pigmentation genes. There was no simple correlation between pigmentation gene expression and dopa oxidase activity or total melanin content of the 14 melanoma cell lines in culture. In the majority of cells, there was no appreciable pigment, whereas, in contrast, half of the cells showed significant dopa oxidase activity. Upregulation of dopa oxidase activity was achieved by alpha-MSH in two out of four cell lines examined in detail and with IBMX in three out of four of these cell lines. IBMX increased tyrosinase gene expression in all four cell lines; alpha-MSH was without effect; and TRP-1 and TRP-2 expression were largely unaffected by IBMX or alpha-MSH. Modest changes in morphology were noted in response to IBMX. Overall, however, human melanoma cell lines were, with two exceptions, amelanotic in culture despite the fact that 10 out of the 14 lines expressed tyrosinase-related genes. We conclude that measurable pigmentation is not a necessary consequence of the expression of pigmentation genes. An implication of this work is that amelanotic tumours in vivo may nevertheless be positive for tyrosinase-related genes.

Comparison of two antiretroviral triple combinations including the protease inhibitor indinavir in children infected with human immunodeficiency virus

OBJECTIVE

The effects of two antiretroviral triple combinations including the protease inhibitor indinavir on the surrogate markers, viral load and CD4 cells were evaluated.

METHODS

Fifteen patients with high viral load or disease progression under their prior antiretroviral therapy were switched to zidovudine/lamivudine/indinavir (Group A, n = 10) or stavudine/lamivudine/indinavir (Group B, n = 5). Serial determinations of viral load and CD4 cells were performed.

RESULTS

The median reduction of the viral load was 0.6 log after 3 months and 0.8 log after 6 months in Group A and 2.5 and 2.4 log after 3 and 6 months in Group B, respectively. After 3 and 6 months 3 of 10 patients in Group A and 3 of 5 patients in Group B had viral load reductions below the detection limit of the assay. Patients with an additional switch of nucleoside analogues at start of indinavir therapy (regardless of the specific reverse transcriptase inhibitor used) had significantly better reductions of the viral load than patients without such a switch (median 2.3 log vs. 0.2 log after 6 months, P < 0.05). In Group A the median of the relative increase of CD4 cells was 37% after 3 months and 57% after 6 months (P = 0.002); in Group B the medians of the relative increase of CD4 cells were 145 and 163% (not significant), respectively. Two patients from Group A and 1 from Group B developed renal calculi, which resolved after adequate hydration. One patient was withdrawn because of intractable vomiting attributed to indinavir.

CONCLUSION

In a small cohort of HIV-infected pediatric patients with extensive prior antiretroviral treatment, triple therapy including indinavir had a sustained effect on the decrease of the viral load and the increase of CD4 cells similar to results obtained in antiretrovirally experienced adults. This effect was significantly better in patients with an additional switch of a nucleoside analogue at start of triple therapy with indinavir than in patients without such a change.

Elevated plasma levels of transforming growth factor (TGF)-beta1 and TGF-beta2 in patients with disseminated malignant melanoma

Overexpression of transforming growth factor-beta isoforms (TGF-beta1, -beta2, -beta3) has been previously reported in human melanoma cell lines and tumours. The aim of the present study was to evaluate the plasma levels of TGF-beta isoforms in melanoma patients. Significantly elevated levels of TGF-beta1 (4.2 x the controls, P = 0.0094) and of TGF-beta2 (1.5 x the controls, P = 0.012) but not of TGF-beta3 were measured in patients with disseminated but not locoregional melanoma. These results indicate systemic circulation of potentially immunosuppressive peptides of the TGF-beta family in end-stage melanoma patients.

Elevated plasma levels of transforming growth factor (TGF)-beta1 and TGF-beta2 in patients with disseminated malignant melanoma

Overexpression of transforming growth factor-beta isoforms (TGF-beta1, -beta2, -beta3) has been previously reported in human melanoma cell lines and tumours. The aim of the present study was to evaluate the plasma levels of TGF-beta isoforms in melanoma patients. Significantly elevated levels of TGF-beta1 (4.2 x the controls, P = 0.0094) and of TGF-beta2 (1.5 x the controls, P = 0.012) but not of TGF-beta3 were measured in patients with disseminated but not locoregional melanoma. These results indicate systemic circulation of potentially immunosuppressive peptides of the TGF-beta family in end-stage melanoma patients.

RT-PCR for tyrosinase-mRNA-positive cells in peripheral blood: evaluation strategy and correlation with known prognostic markers in 123 melanoma patients

Reverse transcriptase polymerase chain reaction for the detection of tyrosinase-mRNA-positive cells in peripheral blood of melanoma patients, as a possible marker of hematogenous dissemination, has demonstrated varying detection rates. This study examined the sensitivity and reproducibility of the technique using a protocol of multiple polymerase chain reaction to determine circulating melanocytic cells. For each of the 123 melanoma patients included in this study, four nested polymerase chain reactions were performed from two blood specimens requiring both polymerase chain reactions from at least one blood sample to be positive to consider a patient as positive. Thus, a definitive result was obtained in 98% of the cases, whereas only 1.6% lacked conclusive findings. Thus, we found a correlation between the tyrosinase detection rate and the clinical stage. Circulating tyrosinase-mRNA-positive cells were detected in 13% of patients with primary tumor, 17% with regional skin/lymph node metastasis, and 44% with distant metastasis. Positivity also correlated with known melanoma progression markers such as gender, tumor thickness, and histologic type. Positive results were obtained more frequently in (i) men compared with women, (ii) patients with thick primary melanomas (> 4 mm: 38%) compared with those with thinner tumors (1.1-4 mm, 22%; < or = 1 mm, 5%), and (iii) patients with nonclassifiable (38%), nodular (34%), and occult primary melanomas (30%) compared with those with acrolentiginous (17%), superficial spreading (9%), or lentigo maligna melanoma (0%). These findings suggest that detection of tyrosinase-mRNA-positive cells in peripheral blood is not an adequate marker for identifying melanoma patients with distant metastasis. Reverse transcriptase polymerase chain positivity in early melanoma stages, however, as corresponding to other prognostic parameters, may indicate increased risk for the development of hematogenous metastasis and may be of value as a progression marker.

Ovariectomy augments B lymphopoiesis and generation of monocyte-macrophage precursors in rat bone marrow

To investigate the effects of estrogen depletion on hematopoiesis and bone turnover, female rats were either ovariectomized (OVX) or sham operated and killed at 1, 2, 3, and 4 wk postsurgery. Flow cytometric analysis of bone marrow cells (BMC) revealed that, in close temporal association with the rise in bone turnover as measured by bone histomorphometry, the number of Thy 1.1+ and KiB1R+ BMC increased two- to threefold in OVX rats relative to sham controls. The Thy 1.1+ BMC were further characterized as Thy 1.1+/KiB1R+ and Thy 1.1+/HIS24+ double-positive cells of the B cell lineage. A transient rise in ED1+ myeloid cells expressing a lysosomal antigen specific for the monocyte-macrophage and osteoclast lineage coincided with the upregulation of osteoclast numbers in OVX rats at 2 wk postsurgery, but the number of ED8+ myelomonocytic BMC remained unchanged. Administration of estradiol prevented the rise in Thy 1.1+, KiB1R+, and ED1+ BMC in OVX animals. Our study indicates that ovariectomy upregulates B lymphopoiesis in rat bone marrow and increases myeloid cell differentiation into the monocyte-macrophage and possibly also the osteoclast lineage.

Increased immune response elicited by DNA vaccination with a synthetic gp120 sequence with optimized codon usage

DNA vaccination elicits humoral and cellular immune responses and has been shown to confer protection against several viral, bacterial, and parasitic pathogens. Here we report that optimized codon usage of an injected DNA sequence considerably increases both humoral and cellular immune responses. We recently generated a synthetic human immunodeficiency virus type 1 gp120 sequence in which most wild-type codons were replaced with codons from highly expressed human genes (syngp120). In vitro expression of syngp120 is considerably increased in comparison to that of the respective wild-type sequence. In BALB/c mice, DNA immunization with syngp120 resulted in significantly increased antibody titers and cytotoxic T-lymphocyte reactivity, suggesting a direct correlation between expression levels and the immune response. Moreover, syngp120 is characterized by rev-independent expression and a low risk of recombination with viral sequences. Thus, synthetic genes with optimized codon usage represent a novel strategy to increase the efficacy and safety of DNA vaccination.

Diversity of the immunodominant epitope of gp41 of HIV-1 subtype O and its validity for antibody detection

The immunodominant regions of the gp41 from 13 HIV-1 subtype O strains from Cameroon, 11 from France and one from Germany were sequenced. The amino acid sequences were compared to those of the 3 published HIV-1 subtype O isolates, ANT70, MVP-5180 and VAU. All HIV-1 subtype O isolates had a very conserved amino acid sequence in this region and showed a subtype O specific structure. Within the cysteine loop there was a positive charge of two basic amino acids, arginine and lysine. Only two strains (CM.6778 and CM.8161) showed an acidic amino acid in this loop. None of the isolates showed the same amino acid sequence in this immunodominant region. A 25 residue peptide from the immunodominant domain of gp41 of the MVP-5180 strain was synthesized, cycled to form the cysteine-loop and coated to microtiter plates. Antibody binding was detected by indirect ELISA using an enzyme labeled anti-human IgG. Out of 111 anti-HIV-1 positive specimens, collected mainly from Cameroonian HIV infected patients, only 10 were not reactive in this assay. The 42 anti-HIV-1 subtype O positive specimens gave all a reaction above cut off. Despite the diversity found in the amino acid sequences within the 25 isolates a peptide-based indirect ELISA representing the immunodominant epitope of the strain MVP-5180 successfully detected all the anti-HIV-O sera so far tested, pointing to the importance of adding such a peptide for correct identification of HIV-1 subtype O infected patients, while some assays without HIV-O specific antigens partially fail to detect all anti-HIV-O specimens.

Evaluation of a quantitative double ELISA strategy for confirmation and differentiation of HIV infection

The current HIV pandemic is complicated by the spread of distinct types and subtypes of HIV. The currently used conventional diagnostic tests have shown limitations in the detection of antibodies against all HIV-1 subtypes, as demonstrated by recent identification of HIV-1 subtype O. To evaluate quantitatively the diagnostic potential of a double ELISA strategy for the detection and partial differentiation of HIV-1, HIV-1 subtype O and HIV-2 infections blood samples were examined at five different test centers: Blantyre, Malawi; Abidjan and Daloa, Ivory Coast; Yaoundé, Cameroon; Munich, Germany. All tests results, including ELISA extinction values and Western blot profiles, were forwarded to Munich for final interpretation. An indirect anti-HIV-1/2 ELISA and a competitive anti-HIV-1 ELISA were used in combination for the initial screening of blood specimens. All anti-HIV positive and anti-HIV negative samples were subjected to immunoblot analysis. Independent of the diversity of the extinction profiles, and of the test manufacturer, the quantitative evaluation of the ELISA extinction values could define two extinction areas with a 100% predictive value for HIV-1 seropositivity and HIV seronegativity; extinction values > 2 by the indirect ELISA and < 0.2 by the competitive ELISA for an anti-HIV-1 subtype A to I positive result; extinction values < 0.2 by the indirect ELISA and > 1.0 by the competitive ELISA for an anti-HIV negative result. Additionally, the quantitative evaluation of the extinction profile provides partial information on the HIV-1 subtype as far as the distinction in group M and group O is concerned. In conclusion, the quantitative evaluation of this double ELISA strategy can reduce the number of blood specimens that require additional confirmatory testing in developing countries and can be superior to the immunoblot method during early seroconversion.

Translation initiation factor eIF-4A1 mRNA is consistently overexpressed in human melanoma cells in vitro

The oncogenic potential of translation initiation factors (eIF-4E and eIF-2alpha) has been described in previous studies leading to the definition of translational oncogenes. Two previously isolated cDNA clones, expressed differently in human melanoma cells and normal human melanocytes, were identified in this study as coding for the translation initiation factor eIF-4A1. Northern-blot analysis revealed consistent overexpression of eIF-4A1 mRNA in a panel of 14 melanoma cell lines (on an average 5.6 times higher than in cultures of normal human melanocytes). In contrast, the mRNAs of the other group-4 translation initiation factors (eIF-4A2, eIF-4B, eIF-4E and eIF-4gamma) were less and not consistently elevated. Cultures of congenital melanocytic nevi exhibited intermediate expression of eIF-4A1. Thus, eIF-4A1 overexpression seems to be an important feature of melanoma cells and might contribute to their malignant transformation.

Detection of genetically diverse human immunodeficiency virus type 1 group M and O isolates by PCR

A panel of 136 genetically diverse group M and 5 group O adult isolates from outside the United States and Europe were evaluated by PCR with the Roche AMPLICOR HIV-1 test, a modified version of the AMPLICOR HIV-1 test, and a new primer pair/probe system. Detection of some of these isolates was less efficient with the AMPLICOR HIV-1 test; however, the assay was significantly improved by reducing the sample input and lowering the annealing temperature. The new primer pair/probe set detected 140 of 141 isolates, including the 5 group O isolates that were not detected with either of the AMPLICOR HIV-1 test formats.

L-ascorbic acid inhibits UVA-induced lipid peroxidation and secretion of IL-1alpha and IL-6 in cultured human keratinocytes in vitro

We investigated the antioxidative effect of L-ascorbic acid on lipid peroxidation and on secretion and mRNA expression of IL-1alpha and IL-6 after UVA irradiation (20 J/cm2) in cultured human keratinocytes. Lipid peroxidation was measured by (i) high performance liquid chromatography with UV detection of malondialdehyde (MDA) at 256 nm and (ii) spectrometric measurement of thiobarbituric acid-reactive substances (TBARS). To evaluate UV-induced cytotoxicity, we assessed cell membrane damage by measuring lactate dehydrogenase (LDH) release. UVA-induced lipid peroxidation in cultured human keratinocytes was inhibited by ascorbic acid in a concentration-dependent manner: MDA protein equivalent was reduced by 47% (10(-6)), compared to keratinocytes not exposed to L-ascorbic acid (p < 0.05), and the TBARS showed a concentration-dependent decrease of 49% (10(-6) M) in L-ascorbic acid-supplemented cultures compared to controls (p < 0.05). LDH release was decreased by 45% in L-ascorbic acid-supplemented keratinocyte cultures, indicating protection against cell death (p < 0.05). L-Ascorbic acid was able to downregulate IL-1alpha mRNA expression in both UVA-irradiated and nonirradiated cells; however, IL-6 mRNA expression remained unaffected. The secretion of these cytokines was reduced nearly to normal in the presence of L-ascorbic acid. These findings indicate a major cell-protective effect of L-ascorbic acid on UVA-induced lipid peroxidation and the secretion of pro-inflammatory cytokines by UVA-irradiated human keratinocytes.

Effect of antiretroviral combination therapy (zidovudine/didanosine or zidovudine/lamivudine) on quantitative plasma human immunodeficiency virus-ribonucleic acid in children and adolescents infected with human immunodeficiency virus

OBJECTIVE

To assess human immunodeficiency virus (HIV) ribonucleic acid load in children and adolescents with HIV infection who are being treated with antiretroviral combination therapy.

STUDY DESIGN

Five patients whose disease progressed with their prior antiretroviral therapy had treatment regimens changed to zidovudine (ZDV)/didanosine (DDI) (group A), and the regimens of six patients were changed to ZDV/lamivudine (3TC) (group B). Patients were followed every 4 to 8 weeks for an average period of 8.6 months. Serial determinations of viral copy numbers and CD4 cells were performed.

RESULTS

In group A patients' mean relative changes in CD4 cells showed a 20% increase after 4 months (difference not significant (NS)) and a return to baseline after 8 months; in group B patients' mean relative increases of CD4 cells were 72% (p = 0.046) and 50% (NS), respectively. In group A mean relative viral load increased 21% (0.08 log10, NS) and 71% (0.23(10) log, NS), whereas in group B viral load decreased 22% (0.1 log10, NS) and 74% (0.58 log10, p = 0.03) after 4 and 8 months, respectively. After starting antiretroviral combination therapy in group A, there was a slight trend of a decreasing ratio of viral load per number of CD4 cells, whereas in group B this ratio significantly decreased, indicating a marked suppression of viral turnover with ZDV/3TC treatment.

CONCLUSION

In a small cohort of pediatric patients, combination therapy with ZDV/3TC was well tolerated and had a strong and sustained effect on the decrease of viral loads similar to results obtained in adults. In patients with ZDV/DDI therapy the reduction of viral load was less pronounced, but treatment groups A and B were not comparable for statistic evaluation.

[Bone marrow morphology and various hemolytic markers in growing rats with alimentary lead deficiency]

The effects of an alimentary lead deficiency on bone marrow morphology and several laboratory parameters of hemolysis were examined in two growth- and one generation-experiments with female Sprague Dawley rats. The animals were fed a semisynthetic casein-based diet supplemented with 0 ppb up to 800 ppb lead as Pb-II-acetat-3-hydrate. The evaluation of bone marrow did not show differences among the groups with different lead supply in the diet. Concerning the laboratory parameters of hemolysis it has been shown that the hemoglobin concentration of plasma and the lactate-dehydrogenase activity of serum were increased and the haptoglobin concentration of serum was decreased in the groups fed the diets poor in lead relative to lead-adequate animals. The activity of glutathione peroxidase and the glutathione concentration in red blood cells were increased in the groups fed the lead-deficient diet compared to lead-adequate groups. In conclusion, the study shows that the pancytopenia observed recently in lead-deficient rats is not caused by disturbed hematopoesis, whereas some parameters measured suggest that there exists increased hemolysis in lead-deficient rats.

Fucosyltransferase III and sialyl-Le(x) expression correlate in cultured colon carcinoma cells but not in colon carcinoma tissue

The potential contribution of fucosyltransferases to the overexpression of sialyl-Le(x) antigen was investigated in the colon carcinoma cell line HT-29 and in human colon carcinoma tissue. In HT-29 cells as well as in normal or malignant colonic tissues Fuc-TIII, Fuc-TIV, Fuc-TVI but not Fuc-TV nor Fuc-TVII were detectable after RT-PCR. Sodium butyrate treatment of HT-29 cells increased (to about 200%) and DMSO treatment decreased (to about 20%) the expression of sialyl-Le(x). This modulation of sialyl-Le(x) was concomitant with the analogous increase/decrease of mRNA of Fuc-TIII but not Fuc-TIV. Fuc-TVI was not detectable by Northern blotting in HT-29 cells. In six human colon carcinomas which exhibited strong overexpression of sialyl-Le(x), the expression of Fuc-TIII-mRNA was the same or lower than in the corresponding normal colonic tissue. Thus Fuc-TIII expression may be affecting the expression of the sialyl-Le(x) moiety in HT-29 cells but not in human colon carcinoma tissue.

bli-4, a gene that is rapidly induced by blue light, encodes a novel mitochondrial, short-chain alcohol dehydrogenase-like protein in Neurospora crassa

Blue light plays an important role in developmental control throughout nature. The bli-4 gene of Neurospora crassa, together with bli-3, al-1 and al-2, is rapidly inducible by blue light. Induction leads to a ninety-fold increase in transcription rate over the dark control level, and the gene therefore appears to be of prime importance in the blue-light induction pathway of N. crassa. We describe the sequencing and analysis of bli-4 and the 38 kDa protein it encodes. We show that the protein is very rapidly imported into the mitochondria and exhibits high homology with the family of short-chain alcohol dehydrogenases.

[Hematologic changes in alimentary Pb deficiency in growing rats]

The effect of an alimentary Pb-deficiency on hematological parameters was examined in two growth- and one generation-experiments with female Sprague Dawley rats. The animals were fed a semisynthetic casein-based diet supplemented with 0 ppb up to 800 ppb Pb as Pb-II-acetate-3-hydrate. In two experiments the blood parameters of the rats of G0-generation fed the diet poor in Pb were changed to a normocytic, normochrome pancytopenia at day 21 resp. 28 of the experiments. At day 28 resp. 41 the blood parameters normalized resp. the different Pb-supply in the diet only effected the mean corpuscular volume- and mean corpuscular hemoglobin-values. It was assumed that the disturbances in blood parameters at deficient Pb-supply are caused by temporary hemolysis.

[Bloodless prostate treatment using high-intensity focused ultrasound (HIFU)]

High intensity focused ultrasound (HIFU) is a technique whereby energy with resultant heat and tissue destruction can be delivered to a discreet distant site without injury to intervening tissue. 27 patients with bladder outlet obstruction and 5 men with loco-regional prostate cancer were treated by this method. At 3 months' follow-up a highly significant improvement of objective and subjective parameters could be demonstrated. No significant complications of this minimally invasive technique have been encountered. Moreover, our preliminary experience suggests that transrectal HIFU may control localized prostate cancer with minimal morbidity and that retreatment is possible at any time without toxicity to surrounding structures.

HIV-1 subtype O: epidemiology, pathogenesis, diagnosis, and perspectives of the evolution of HIV

HIV-1 subtype O is a new HIV variant originating in the West-Central African region, with highest prevalences in countries such as Cameroon, Equatorial Guinea and Gabon. Detection of antibodies to HIV-1 subtype O can pose problems in unmodified ELISA tests, and confirmation of anti-HIV-1 subtype O in immunoblot may give false negative results in some specimens. Nucleic acid-based assays designed for HIV-1 detection do not amplify or detect sequences from HIV-1 subtype O. In their env sequences, HIV-1 subtype O strains show a higher heterogeneity than the classical HIV-1 subtypes, leading to the conclusion that HIV-1 subtype O has been introduced into the human population only recently. Further, unidentified subtypes are also likely to exist.

Incomplete expression of the tyrosinase gene family (tyrosinase, TRP-1, and TRP-2) in human malignant melanoma cells in vitro

Sequence analysis of two clones found repressed in melanoma cell lines in earlier studies showed 9F2 to be identical with the TRP-1 gene and 6F5 with TRP-2 containing a long untranslated 3' end. For further investigation of the expression of the tyrosinase gene family in normal and malignant melanocytic cells, a series of melanoma cell lines and of cultured melanocytes were analyzed by Northern blotting and by reverse transcriptase-polymerase chain reaction (RT-PCR). The Northern blots were probed with cDNA fragments specific for TRP-1, TRP-2, and tyrosinase, for nested tyrosinase-PCR the outer primers specified a 284 bp and the nested primers a 207 bp fragment. Investigations on 14 established melanoma cell lines grown in different media compared with seven normal human melanocyte (NHM) cultures revealed that all three pigment genes were expressed in NHM, whereas pigment gene expression was found repressed in nearly all melanoma cell lines and was completely absent in 4 of 14 specimen. In particular, tyrosinase and TRP-2 genes were found always to be expressed together, and TRP-1 mRNA alone was absent in four melanoma cell lines. Negativity of cultured melanoma cells for tyrosinase mRNA was confirmed by nested RT-PCR, and gene deletion was ruled out by genomic Southern blots. The gene expression seemed independent from the type of medium used for cultivation. These findings indicate repressed or lacking expression of pigment genes in melanoma cell lines, most likely due to regulatory mechanisms, and that differences may exist between tyrosinase and TRP-2 on one hand and TRP-1 on the other. Overall, it seemed that RT-PCR for tyrosinase has limited value for identifying melanoma cells in the peripheral blood of melanoma patients; TRP-1, TRP-2, and other, additional markers may be required.

Reduced capacity of antibodies from patients infected with human immunodeficiency virus type 1 (HIV-1) group O to neutralize primary isolates of HIV-1 group M viruses

Neutralizing antibody patterns in sera of persons infected with human immunodeficiency virus type 1 (HIV-1) groups M and O to their homologous and heterologous primary isolates were determined in a peripheral blood mononuclear cell-based neutralization assay and correlated with their ability to bind to V3 loop synthetic peptides. Most HIV-1 group M sera (9/16) neutralized HIV-1 group O viruses, whereas fewer group O sera (3/13) only weakly neutralized HIV-1 group M viruses. Group M sera neutralizing HIV-1 group O viruses neutralized other HIV-1 group M viruses with titers of 1:10-1:1280. V3 loop binding capacity of sera did not reflect their neutralizing capacity of the homologous isolate. Despite the reduced neutralizing capacity of group O-infected patients' sera to group M viruses, some group M-infected patients' sera neutralized both HIV-1 group M and O isolates, suggesting that they share some conserved neutralizing epitopes.

Gegenwärtiger Stand der Virusinfektionen in Mitteleuropa

Virale Infektionsgefahren für den Transfusionsempfänger gehen meistens von chronisch infizierten Spendern aus. Nach Einführung geeigneter Tests konnten die Übertragungsrisiken für Hepatitis-B-Virus, Hepatitis-C-Virus und für das Humane Immunschwäche-Virus auf ein sehr geringes Niveau zurückgedrängt werden. Ob das restliche Übertragungsrisiko, sowohl für diese Viren als auch für naturgemäß im gesunden Spender selten vorkommende, akute Virusinfektionen, durch zusätzliche Erreger-unspezifische Testverfahren beeinflußt werden kann, ist derzeit noch nicht beantwortbar.

Resistance of HIV type 1 to proteinase inhibitor Ro 31-8959

During replication of human immunodeficiency virus type 1 (HIV-1), proteolytic cleavage of Gag and Gag-Pol precursor proteins into different functional protein subunits is catalyzed by the viral proteinase, and this enzyme is the target of the antiviral proteinase inhibitor, Ro 31-8959. We investigated in vitro which HIV mutants with reduced sensitivity to Ro 31-8959 emerged during proteinase inhibition treatment; from three different HIV-1 strains, comparable progeny virus resistant to proteinase inhibitor were found, whereas the same experimental protocol detected no resistant HIV-2 mutants. Molecular analysis of the mutations underlying resistance revealed a multistep mechanism in which an amino acid exchange was common to all resistant isolates, and in all experiments preceded further exchanges at position 90 (leucine to methionine) and/or at position 54 (isoleucine to valine). For wild-type strains the 90% inhibitory concentrations of Ro 31-8959 were close to 20 nM, whereas HIV-1 mutants with all 3 amino acid exchanges had more than 50-fold increased 90% inhibitory concentrations (above 1000 nM). The primary event (Gly-48 to valine) occurs at the hinge of the flaps of the proteinase, thus hampering entry of the inhibitor to the active center and suggesting steric hindrance. Detailed knowledge of this stereotypic process could open inhibitor design, thus preventing conceivable escape of resistant virus on proteinase inhibitor action.

Identification of genes specifically regulated in human melanoma cells

In order to improve the characterization of human malignant melanoma cells and their variant gene expression in vitro, a search for specifically regulated genes was performed. Four melanoma cell lines (M5, MEWO, IGR39, SKMEL13) and newly cultured normal human melanocytes were included in a comparative hybridization (differential screening) of a human melanoma cDNA-library. Six cDNAs were isolated showing a stronger expression (four genes) or a weaker expression (two genes) in melanoma cells than in normal human melanocytes. Quantification of the expression patterns of the two repressed genes in Northern blots revealed general expression in all melanocyte cultures examined, no expression in three cell lines (M5, IGR39, SKMEL13) and weak expression in MEWO. The four induced genes were found to be only weakly expressed in normal human melanocytes, but showed an elevated expression in all of the four melanoma cell lines tested. Thus, using the technique of differential screening, consistent gene regulation at the messenger RNA level was identified, which distinguishes the four melanoma cell lines tested from normal melanocytes. We conclude from the expression patterns that specific gene regulation in melanoma cells in vitro is characterized both by strong repression of some melanocyte genes, as well as by the induction of other genes, but there was no indication of new expression of genes specific for melanoma cells. Because of the uniform induction or repression in different melanoma cell lines, it is conceivable that the cloned genes may be involved in the malignant transformation of melanocytic cells.

Reactivity of five anti-HIV-1 subtype O specimens with six different anti-HIV screening ELISAs and three immunoblots

Five anti-subtype O specimens were tested by anti-HIV-1/2 screening and confirmatory assays. They can be divided into three specimens, reactive with all ELISAs, independent of the nature of the antigen (recombinant proteins or peptides) and test configuration (indirect ELISA or double antigen/sandwich ELISA). One specimen was not detected by one peptide based ELISA. One specimen was only recognized by two ELISAs and should be considered as a marker sample for the weakness of currently used ELISAs with anti-subtype O. Three different immunoblot assays available commercially detected two of the specimens with a major binding of gp160 and other viral bands, especially the integrase and reverse transcriptase. Another two specimens lacked reactivity with glycoproteins almost completely, but showed some staining with the enzymes of HIV, and would most probably be interpreted as indeterminate. The fifth specimen, which was also missed by most of the ELISAs, had very faint staining of the gp160 and a very weak staining of p24, and would most probably be interpreted as negative. Adaption of currently available tests to anti-subtype O is needed for the future reliability of anti-HIV diagnostic reagents.

Renal cell carcinoma extending into the vena cava: surgical approach, technique and results

OBJECTIVE

To describe the technique and results of a thoraco-abdominal approach to removing the caval thombi in patients with renal cell carcinoma extending into the vena cava.

PATIENTS AND METHODS

Between 1970 and 1990 35 patients presenting with renal cell carcinoma extending into the vena cava were treated at the Department of Urology, Innsbruck. Twenty-three of these patients underwent radical tumour nephrectomy including cavotomy and thrombectomy or caval resection. A transabdominal approach had been used in this department for radical tumour nephrectomy including cavotomy and thrombectomy or caval resection until 1987. Since 1988, a thoraco-abdominal approach has been employed. In group I patients the approach was via the seventh intercostal space, whereas in group II and III patients the thoraco-abdominal incision was made through the fifth intercostal space. In the present study the anatomy of the thoraco-abdominal approach is described.

RESULTS

Tumour staging and grading yielded stage T3b in 15 patients (grade I, 1; grade II, 6; grade III, 8); another eight patients with stage T3b were found to have metastatic disease (N1, 6; N2, 2; M1, 3). On the basis of the extension of the caval thrombus the patients were classified as follows: group I, 16; group II, 3; group III, 4. In T3b N0 M0 patients the 5-year-survival rate was 62.5%, while in patients with positive lymph nodes the mean survival rate was 15.5 months.

CONCLUSION

Our results suggest that the thoracoa-abdominal approach is the method of choice for the safe removal of renal cell carcinomas associated with caval thombi. If resection of the caval tumour is complete, prognosis is dependent on known factors, such as tumour invasion, nodal involvement and distant metastases rather than the extension of the tumour thrombus. An aggressive approach is not warranted in patients with nodal involvement and/or distant metastases, as it does not improve survival.

Tumour necrosis factors and several interleukins inhibit the growth and modulate the antigen expression of normal human melanocytes in vitro

In the present study the action of various cytokines as regulators of human melanocyte growth and differentiation was examined in vitro. Primary melanocyte cultures were obtained in complete medium free of 12-O-tetradecanoylphorbol-13-acetate or serum. First passage melanocytes were treated with various concentrations of recombinant tumour necrosis factor alpha and beta (rTNF-alpha, rTNF-beta), as well as with various recombinant interleukins (rIL-1a, rIL-1b, rIL-2, rIL-3, rIL-4 and rIL-6) for 6 days in complete medium and for 6 and 12 days in a mitogen-reduced medium variant. The 4-methylumbelliferyl heptanoate fluorometric microassay and Ki-67 staining were used for assessing cell proliferation, and the immunophenotype was evaluated using various monoclonal antibodies. Melanocyte proliferation in complete medium was inhibited by rTNF-alpha (-24%), rTNF-beta (-17%), rIL-1a (-21%), rIL-1b (-18%) and rIL-6 (-29%); in contrast, rIL-2, rIL-3 and rIL-4 had no antiproliferative effect. Measurements of Ki-67-positive nuclei confirmed these results. In the reduced medium variant, none of the above cytokines inhibited melanocyte proliferation. Recombinant TNF-alpha and rTNF-beta markedly reduced the expression of the pigment cell-associated antigens HMB-45 and K.1.2, and they enhanced the expression of VLA-2, ICAM-1 and HLA class I antigens and strongly induced HLA-DR. Similar changes were induced by rIL-1a, rIL-b and rIL-6, and rIL-2 decreased the expression of HLA class I antigens and of ICAM-1. In conclusion, several cytokines inhibited the growth and modulated the phenotype of melanocytes in vitro.(ABSTRACT TRUNCATED AT 250 WORDS)

Photodynamic action of ultraviolet A: induction of cellular hydroperoxides

Long-wavelength ultraviolet radiation (UVA) can cause cancer. A carcinogenic mechanism involved may be the induction of harmful reactive oxygen species resulting from photodynamic effects. UVA is generally assumed to induce photodynamic effects, but evidence from experiments with viable biological materials has been indirect until present. Here we measured the induction of (lipid) hydroperoxides as direct indicators of photodynamic reactions. Cultured human fibroblasts were irradiated with 10J UVA/cm2. The induced hydroperoxides were measured by an enzymatic method using glutathione peroxidase and glutathione reductase (GR). Additionally, reduced glutathione (GSH) was determined as parameter for the constitutive antioxidant defense. UVA was found to increase lipid hydroperoxides in fibroblasts by 116% (p < 0.001), when compared to nonirradiated controls. Conversely GSH was decreased in the irradiated cells by 51% (p < 0.001). Because of the induced hydroperoxides, it is concluded that the UVA effects were mediated by a photodynamic mechanism. The photodynamic mechanism resulted in the formation of reactive oxygen species and the consumption of constitutive antioxidants. This suggests a role for antioxidants during the photodynamic mechanism. Photodynamic mechanisms may play a crucial role in carcinogenic events, especially after UVA.

Protein patterns of benign and malignant human melanocytes show consistent changes in gene expression

For human malignant melanoma, no pattern of oncogene activation has yet been identified which consistently occurs in the malignant cells. In order to better understand the transformation process, we studied the overall gene expression at the protein level in human melanoma cells in vitro by two-dimensional gel electrophoresis. For that, four established cell lines, MEWO, M5, SKMEL13, and IGR39, were used and compared with newly established cultures of normal human melanocytes. Considerable variations in the protein patterns of the different melanoma cell lines were found, whereas the patterns of normal human melanocytes correlated fairly well with each other. With respect to the expression of single proteins, we identified four major proteins which were consistently found in cultured melanocytes and stringently repressed in the four melanoma cell lines examined. On the other hand, induction of new proteins in the different melanoma cell lines was found to be less stringent and also less uniform. We propose that malignant transformation of melanocytes may be more associated with the suppression of melanocytic proteins rather than with new expression of melanoma specific proteins.

Androgen receptor alterations in patients with disturbances in male sexual development and in prostatic carcinoma

The androgen receptor, a ligand-activated nuclear transcription factor belonging to the large superfamily of nuclear receptors, mediates the intracellular action of androgens. It plays a central role in male sexual development and in prostatic carcinoma as a target of endocrine therapy. We have looked for androgen receptor mutations as a cause of male sexual ambiguity and as a possible reason for failure of androgen ablation therapy on prostatic carcinoma. In 5 patients of 2 families with perineoscrotal hypospadia and undescended testes, we have identified a mutation ala596-->thr in the DNA-binding domain of the androgen receptor. This mutation interferes with DNA binding of the receptor. Reactivation of this mutant receptor by binding of an antibody or by interaction with other proteins and by exchange of the amino acid thr602-->ala indicates that the dimerization step is affected. A point mutation ser703-->gly was detected in a newborn male child with perineoscrotal hypospadias. This mutation decreased receptor-hormone affinity. As a consequence its transactivation activity was dependent on the androgen concentration. Although the molecular mechanisms of these two mutations are completely different, both resulted in partial androgen insensitivity and interfered with virilization in the affected patients. A different kind of mutation was present in a tumor specimen derived from an advanced therapy-resistant prostatic carcinoma. This point mutation resulted in exchange of valine-->methionine at amino acid position 715 in the receptor protein. In contrast to the former two mutations this receptor showed a gain in function.(ABSTRACT TRUNCATED AT 250 WORDS)

Neurospora crassa blue light-inducible gene bli-3

Blue light induces various physiological, morphological and biochemical reactions in the filamentous fungus Neurospora crassa. This light response is accompanied by a global change in gene expression, and several light-inducible transcripts (bli-genes) have been cloned. We isolated the genomic clone of the gene bli-3, whose mRNA we have previously shown to be induced 2 minutes after the beginning of illumination. Its DNA sequence predicted a transcriptional unit of 1050 bp encoding a novel, hydrophilic protein of 209 aminoacids. Comparison to other N. crassa genes revealed a group of inducible genes which share this promoter structure: a well conserved TATA-box, similar transcription start box (TCATCANC) and repeats of pyrimidines (CT) between these boxes. Based upon this group, we propose a consensus sequence for one possible type of inducible promoter in N. crassa.

P53 mutation and c-fos overexpression are associated with detection of the antigen VLA-2 in human melanoma cell lines

In this study, we examined the expression of c-fos, c-myc, mutant c-Ha-ras and mutant p53 proteins in three normal human melanocyte cell lines and the following 12 melanoma cell lines: M5, Mewo, A375, Bro, Mel 2a, O-Mel II, IgR 39, SkMel-13, -19, -28 Mel-57 and NKI-4, using an immunohistochemical assay (APAAP). An effort was made to correlate oncogene expression with growth parameters, differentiation antigens (HMB-45, vla-2, k.1.2.58, HLA-DR, HLA-I), and pigmentation. All melanocyte cell lines were negative for the oncogenes examined, whereas six of the melanoma cell lines were found also positive (three for c-fos, two for c-myc, one for c-Ha-ras, and four for p53). Three melanoma cell lines expressed one oncogene and three the combination c-fos/p53. These three melanoma cell lines were positive for the "late" tumor progression marker A. 1.43 (vla-2 adhesion molecule) and negative for the differentiation marker k. 1. 2. 58. Positivity for A. 1. 43 combined with negative staining for k. 1. 2. 58 was found in six out of the 12 cell lines. The observed oncogene expression correlated neither with growth parameters nor melanin content. The present findings revealed a coexpression of mutant p53 and c-fos proteins being associated with a highly malignant phenotype in melanoma cell lines. Further studies are necessary to clarify the significance of the above findings.