Early-career general practitioners' antibiotic prescribing for acute infections: a systematic review

BACKGROUND

Antimicrobial resistance is a worldwide threat, exacerbated by inappropriate prescribing. Most antibiotic prescribing occurs in primary care. Early-career GPs are important for the future of antibiotic prescribing and curbing antimicrobial resistance.

OBJECTIVES

To determine antibiotic prescribing patterns by early-career GPs for common acute infections.

METHODS

A systematic literature search was conducted using PubMed, Embase and Scopus. Two authors independently screened abstracts and full texts for inclusion. Primary outcomes were antibiotic prescribing rates for common acute infections by GPs with experience of 10 years or less. Secondary outcomes were any associations between working experience and antibiotic prescribing.

RESULTS

Of 1483 records retrieved, we identified 41 relevant studies. Early-career GPs were less likely to prescribe antibiotics compared with their more experienced colleagues (OR range 0.23-0.67). Their antibiotic prescribing rates for 'any respiratory condition' ranged from 14.6% to 52%, and for upper respiratory tract infections from 13.5% to 33%. Prescribing for acute bronchitis varied by country, from 15.9% in Sweden to 26% in the USA and 63%-73% in Australia. Condition-specific data for all other included acute infections, such as sinusitis and acute otitis media, were limited to the Australian context.

CONCLUSIONS

Early-career GPs prescribe fewer antibiotics than later-career GPs. However, there are still significant improvements to be made for common acute conditions, as their prescribing is higher than recommended benchmarks. Addressing antimicrobial resistance requires an ongoing worldwide effort and early-career GPs should be the target for long-term change.

The Australia and New Zealand Congenital Outcomes Registry for Surgery (ANZCORS): methodology and preliminary results

BACKGROUND

Analysis of multi-institutional data and benchmarking is an accepted accreditation standard in cardiac surgery. Such a database does not exist for congenital cardiac surgery in Australia and New Zealand (ANZ). To fill this gap, the ANZ Congenital Outcomes Registry for Surgery (ANZCORS) was established in 2017.

METHODS

Inclusion criteria included all cardiothoracic and extracorporeal membrane oxygenation (ECMO) procedures performed at five participating centres. Data was collected by data managers, validated by the surgical team, and securely transmitted to a central repository.

RESULTS

Between 2015 and 2019, 9723 procedures were performed in 7003 patients. Cardiopulmonary bypass was utilized for 59% and 9% were ECMO procedures. Fifty-seven percent (n = 5531) of the procedures were performed in children younger than 1 year of age. Twenty-four percent of procedures (n = 2365) were performed in neonates (≤28 days) and 33% (n = 3166) were performed in children aged 29 days to 1 year (infants). The 30-day mortality for cardiac cases (n = 6572) was 1.3% and there was no statistical difference between the participating centres (P = 0.491). Sixty-nine percent of cases had no major post-operative complications (5121/7456). For cardiopulmonary bypass procedures (n = 5774), median stay in intensive care and hospital was 2 days (IQR 1, 4) and 9 days (IQR 5, 18), respectively.

CONCLUSION

ANZCORS has facilitated pooled data analysis for paediatric cardiac surgery across ANZ for the first time. Overall mortality was low. Non-risk-adjusted 30-day mortality for individual procedures was similar in all units. The continued evaluation of surgical outcomes through ANZCORS will drive quality assessment in paediatric cardiac surgery across ANZ.

Disease burden, associated mortality and economic impact of antimicrobial resistant infections in Australia

BACKGROUND

The growing spread of antimicrobial resistance (AMR) is accepted as a threat to humans, animals and the environment. This threat is considered to be both country specific and global, with bacteria resistant to antibiotic treatment geographically dispersed. Despite this, we have very few Australian estimates available that use national surveillance data supplemented with measures of risk, to generate reliable and actionable measures of AMR impact. These data are essential to direct policies and programs and support equitable healthcare resource utilisation. Importantly, such data can lead to implementation of programs to improved morbidity and mortality of patients with a resistant infection.

METHODS

Using data from a previous case-cohort study, we estimated the AMR-associated health and economic impact caused by five hospital-associated AMR pathogens (Enterococcus spp., E. coli, K. pneumoniae, P. aeruginosa and S. aureus) in patients with a bloodstream, urinary tract, or respiratory tract infection in Australia in 2020. We estimated disease burden based on the counterfactual scenario in which all AMR infections were replaced by no infection.We used a population-level simulation model to compute AMR-associated mortality, loss of quality-adjusted life years and costs.

FINDINGS

In 2020, there were 1,031 AMR-associated deaths (95% uncertainty interval [UI] 294, 2,615) from the five resistant hospital-associated infections in Australia. The greatest odds of dying were from respiratory infections (ceftazidime-resistant P. aeruginosa) and bloodstream infections, both resulting in high hospital and premature death costs. MRSA bacteraemia contributed the most to hospital costs (measured as bed-days) as patients with this infection resulted in additional 12,818 (95% UI 7246, 19966) hospital bed-days and cost the hospitals an extra $24,366,741 (95%UI $13,774,548, $37,954,686) per year. However, the cost of premature death from five resistant pathogens was $438,543,052, which was by far greater than the total hospital cost ($71,988,858). We estimate a loss of 27,705 quality-adjusted life years due to the five AMR pathogens.

INTERPRETATION

These are the first Australian estimates of AMR-associated health and economic impact. Country-level estimates of AMR impact are needed to provide local evidence to better inform programs and health policies to reduce morbidity and mortality associated with infection. The burden in hospital is likely an underestimate of the impact of AMR due to community-associated infections where data are limited, and the AMR burden is high. This should now be the focus of future study in this area.

FUNDING

TMW was supported by the Australian Partnership for Preparedness Research on Infectious Disease Emergencies (APPRISE) (grant number GNT1116530) Fellowship.

Vocal cord dysfunction after pediatric cardiac surgery: A prospective implementation study

Objective

To determine the incidence, outcomes, and evaluate diagnostic modalities for postoperative vocal cord dysfunction (VCD) following cardiothoracic surgery in children.

Methods

A prospective mixed-methods study using principles of implementation science was completed. All patients undergoing surgery involving the aortic arch, ductus, or ligamentum arteriosum and vascular rings from September 2019 to December 2020 were enrolled. Patients underwent speech pathology assessment, laryngeal ultrasound, and flexible direct laryngoscopy.

Results

Ninety-five patients were eligible for inclusion. The incidence of VCD ranged from 18% to 56% and varied according to procedure group. VCD occurred in 42% of neonates. Repair of hypoplastic aortic arch was associated with increased risk of VCD (57%; P = .002). There was no significant difference in duration of intubation, pediatric intensive care unit stay, or hospital stay. Forty percent children were able to achieve full oral feeding. Children with VCD were more likely to require nasogastric supplementary feeding at discharge (60% vs 36%; P = .044). Sixty-eight percent of patients demonstrated complete resolution of VCD at a median of 97 days postoperatively. Laryngeal ultrasound and speech pathology assessment combined had a sensitivity of 91% in comparison to flexible direct laryngoscopy.

Conclusions

VCD occurred in one-third and resolved in two-thirds of patients at a median of 3 months following cardiac surgery. Aortic arch repair carried the highest risk of VCD. VCD adversely influenced feeding. Forty percent of patients achieved full oral feeding before discharge. VCD did not delay intensive care unit or hospital discharge. Speech pathology assessment and laryngeal ultrasound combined was reliable for diagnosis in most patients and was more patient friendly than flexible direct laryngoscopy.

Cost-effectiveness analysis of doctor-pharmacist collaborative prescribing for venous thromboembolism in high risk surgical patients

Background

Current evidence to support cost effectiveness of doctor- pharmacist collaborative prescribing is limited. Our aim was to evaluate inpatient prescribing of venous thromboembolism (VTE) prophylaxis by a pharmacist in an elective surgery pre-admission clinic against usual care, to measure any benefits in cost to the healthcare system and quality adjusted life years (QALYs) of patients.

Method

A decision tree model was developed to assess cost effectiveness of pharmacist prescribing compared with usual care for VTE prophylaxis in high risk surgical patients. Data from the literature was used to inform decision-tree probabilities, utility, and cost outcomes. In the intervention arm, a pharmacist prescribed patient’s regular medications, documented a VTE risk assessment and prescribed VTE prophylaxis. In the usual care arm, resident medical officers were responsible for prescribing regular medications, and for risk assessment and prescribing of VTE prophylaxis. The base scenario assessed the cost effectiveness of a pre-existing pre-admission clinic pharmacy service that takes on a collaborative prescribing role. The alternative scenario assessed the benefits of introducing a pre-admission clinic pharmacy service where previously there had not been one. Probabilistic sensitivity analysis was conducted to explore uncertainty in the model.

Results

In both the base-case scenario and the alternative scenario pharmacist prescribing resulted in an increase in the proportion of patients adequately treated and a decrease in the incidence of VTE resulting in cost savings and improvement in quality of life. The cost savings were $31 (95% CI: -$97, $160) per patient in the base scenario and $12 (95% CI: -$131, $155) per patient in the alternative scenario. In both scenarios the pharmacist-doctor prescribing resulted in an increase in QALYs of 0.02 (95% CI: -0.01, 0.005) per patient. The probability of being cost effective at a willingness to pay off $40,000 was 95% in the base scenario and 94% in the alternative scenario.

Conclusion

Delegation of the prescribing of VTE prophylaxis for high risk surgical patients to a pharmacist prescriber in PAC, as part of a designated scope of practice, would result in fewer cases of VTE and associated lower costs to the healthcare system and increased QALYs gained by patients.

Trial registration

Pre admission clinic study registered with ANZCTR-ACTR Number ACTRN12609000426280.

Genomic Alterations in Human Breast Cancer: A Review

We review and discuss data on the genetic alterations documented in human breast carcinomas at the molecular level. These alterations may result in: 1) deletion of genetic material (chromosome 11p, 13q, 3p, 1q, 17p); 2) amplification of genes or entire chromosomal segments (c-myc, c-erb-B2, locus DF3/PUM, loci on 11q13); 3) rearrangements (c-myc); 4) point mutations (c-ras). Presently available informations do not allow the development of cohesive pathogenetic models but indicate that the molecular basis of human breast cancer is heterogeneous.

Changes in neurosyphilis presentation: a survey on 286 patients

Although neurosyphilis (NS) keeps plaguing worldwide, often with oligosymptomatic and atypical manifestations, the most recent reports fail to provide useful information, like details of the clinical history and even of the previous early therapy. We conducted a survey of the literature of the last 5 years on the clinical presentation of NS, recording the aforementioned inaccuracies. One hundred and thirty-seven articles were collected, reporting on 286 patients. General paresis was the commonest form (49%), often manifesting with cognitive impairment and psychiatric symptoms. Syphilitic meningitis was found in 63 patients (22%), mainly with ocular or auditory involvement. Meningovascular and tabetic form were both found in 12% of cases. Gummatous and epileptic manifestations were rare. Perusal of the literature confirms that NS prevalence is increasing, often with manifestations that are atypical for timing and type of lesions. Unfortunately, many articles are lacking of critical information, like an accurate clinical history and timing of the therapy making difficult to assess the effectiveness of penicillin in preventing NS.

Overexpression of wild-type p53 overrides the mitogenic effect of ri-alpha subunit of protein-kinase-a in human breast cells

Protein kinase A type I (PKAI) and its regulatory subunit RI alpha are overexpressed in cancer cells and are induced by mitogenic hormones and growth factors in nontransformed cells. RI alpha/PKAI are directly involved in the G1>S transition and cell proliferation of non-transformed human breast MCF-10A cells. Retroviral vector-mediated overexpression of RI alpha in these cells (MCF-10A RI alpha) confers the ability to grow in serum-free medium. p53 controls a G1 check point before transition to the S phase, playing a key role in the regulation of cell proliferation and in the preservation of DNA integrity. In this study we evaluated the interaction of p53 and RI alpha on cell cycle progression and cell proliferation of MCF-10A cells. Retroviral vector-mediated overexpression of wild-type p53 in the MCF-10A neo and MCF-10A RI alpha cells determined a marked inhibition of RI alpha protein expression in MCF-10A-p53 cells and induced G0/G1 accumulation, cell gowth arrest and changes in cell morphology not due to apoptosis in both MCF-10A-p53 and MCF-10A RI alpha-p53 cells. On the other hand, in the MCF-10A RI alpha cells we observed an increased expression of the endogenous p53, although these cells were still able to proliferate. These results suggest that overexpression of wildtype p53 acts in a dominant fashion to abrogate the RI alpha induction of G1>S transition and cell proliferation. Moreover, overexpression of RI alpha leads to increased synthesis of endogenous p53 which, however, is unable to interfere with the RI alpha-dependent mitogenic signalling.

Role of Dlx6 in regulation of an endothelin-1-dependent, dHAND branchial arch enhancer

Neural crest cells play a key role in craniofacial development. The endothelin family of secreted polypeptides regulates development of several neural crest sublineages, including the branchial arch neural crest. The basic helix-loop-helix transcription factor dHAND is also required for craniofacial development, and in endothelin-1 (ET-1) mutant embryos, dHAND expression in the branchial arches is down-regulated, implicating it as a transcriptional effector of ET-1 action. To determine the mechanism that links ET-1 signaling to dHAND transcription, we analyzed the dHAND gene for cis-regulatory elements that control transcription in the branchial arches. We describe an evolutionarily conserved dHAND enhancer that requires ET-1 signaling for activity. This enhancer contains four homeodomain binding sites that are required for branchial arch expression. By comparing protein binding to these sites in branchial arch extracts from endothelin receptor A (EdnrA) mutant and wild-type mouse embryos, we identified Dlx6, a member of the Distal-less family of homeodomain proteins, as an ET-1-dependent binding factor. Consistent with this conclusion, Dlx6 was down-regulated in branchial arches from EdnrA mutant mice. These results suggest that Dlx6 acts as an intermediary between ET-1 signaling and dHAND transcription during craniofacial morphogenesis.

The coding region of the human DLX6 gene contains a polymorphic CAG/CCG repeat

The region on chromosome 7q21-22 is frequently altered in several human neoplasias such as uterine leiomyoma, myeloid leukemia and breast cancer. The same region has also been linked to split hand/split foot malformation type 1 and to involutional osteoporosis. Our analysis of genes that map to this region has led to the identification of the so far unknown first exon of the homeobox gene DLX6, a mammalian homologue of the Drosophila distal-less gene. Distal-less is a downstream target of the trithorax transcription factors. Translocations involving the mammalian homologue of trithorax, ALL-1, leading to its constitutive activation cause leukemia. We describe here that the first exons of human and mouse DLX6 genes contain a multiple trinucleotide repeat region. We have analyzed the CAG repeat length in 90 subjects and were able to identify five alleles with 11 to 20 CAG repeats.

Polyethylenimine-based intravenous delivery of transgenes to mouse lung

Generally, cationic vector-based intravenous delivery of DNA is hindered by interactions of positively charged complexes with serum proteins. However, if optimally formulated, cationic vectors can provide reasonable levels of transfection in the lung either by intravenous or intrapulmonary routes. We investigated the in vivo transfection capacity of a cationic polymer: linear, 22 kDa polyethylenimine. PEI/DNA complexes were formulated in 5% glucose and delivered into adult mice through the tail vein. Two marker genes were used, beta-galactosidase and luciferase. High levels of luciferase expression (10(7) RLU/mg protein) were found in the lung when DNA was complexed with PEI at a ratio of 4 nitrogen equivalents per DNA phosphate. Lower levels of transfection were found in the heart, spleen, liver and kidney. Expression was dose- and time-dependent in all tissues examined. In the lung, beta-galactosidase staining showed transgene expression in clusters of 10 or more pulmonary cells including the alveolar endothelium, squamous and great alveolar epithelial cells (type I and II pneumocytes) and septal cells. These findings indicate that the complexes pass the capillary barrier in the lung. Although the delivery mechanism requires elucidation, linear PEI has promise as a vector for intravenous transfer of therapeutic genes.

Cyclin D1 and retinoblastoma susceptibility gene alterations in non-small cell lung cancer

Among the major regulators of the G1 restriction point are cyclin D1 and the retinoblastoma gene product (RB). In non-small cell lung cancer (NSCLC), the cyclin D1 gene is amplified/over-expressed in almost 50% of cases, and RB is inactivated in 6-32% of cases. It is of interest to evaluate concurrently the alterations of both genes on the same series of NSCLCs, to investigate whether cyclin D1 and RB alterations are alternative pathways leading to inactivation of the G1 restriction point or if they can occur in the same tumor, possibly exerting an additive effect on cancer progression. We investigated a series of 57 NSCLCs, analyzing cyclin D1 and RB at the gene and protein levels by Southern blot, Northern blot and immunohistochemistry. The cyclin D1 gene was amplified in 18 cases, cyclin D1 immunoreactivity was seen in 25 tumors. Amplification and expression were significantly associated. RB immunohistochemical expression was absent in 9 of 42 informative cases. RB mRNA expression was low to absent in 9 of 45 informative cases, cyclin D1 amplification was associated with normal RB mRNA, and cyclin D1 over-expression was associated with normal RB immunoreactivity, supporting the hypothesis that alterations of cyclin D1 and RB are alternative mechanisms by which tumor cells may escape the G1 restriction point. A concurrent alteration of RB and cyclin D1 was seen in a small subset of NSCLCs. Abnormalities of cyclin D1 and/or RB at the gene and/or expression level were present in more than 90% of cases, stressing that cyclin D1 and/or RB alterations represent an important step in lung tumorigenesis.

Differential regulation of the zinc finger genes Krox-20 and Krox-24 (Egr-1) suggests antagonistic roles in Schwann cells

Krox-20 and Krox-24 (Egr-1) encode closely related zinc finger transcription factors, which interact with the same DNA target sequences. Krox-20 is required for myelination in the peripheral nervous system. Using lacZ knock-in mutant mouse lines as well as immunohistochemical analyses, we have studied the expression of Krox-20 and Krox-24 in the Schwann cell lineage during normal development and following nerve lesion in the mouse and in human neuropathies. During embryogenesis, the two genes are expressed in a successive and mutually exclusive manner, Krox-24 being restricted to Schwann cell precursors and Krox-20 to mature Schwann cells. At birth, Krox-24 is reactivated and the two genes are coexpressed. In the adult, Krox-20 is expressed in myelinating cells, while Krox-24 is restricted to nonmyelinating cells. Following nerve lesion, Krox-24 is strongly induced in Schwann cells, reinforcing the link between its expression and the nonmyelinating and/or proliferative state, whereas Krox-20 is downregulated. These data are consistent with Krox-20 and Krox-24 playing antagonistic roles during the development of the Schwann cell lineage. In particular, their balance of expression might participate in the choice between myelinating and nonmyelinating pathways.

Down-regulation of the nm23.h1 gene inhibits cell proliferation

nm23 gene expression is strictly related to the state of cell growth. The level of its expression parallels the fraction of thymidine-incorporating cells (S-phase cells) in neoplastic mammary tissues and in the synchronously cycling fraction of MCF 1OA cells. nm23.h1 reaches a peak of expression in the S-phase, and is present at very low level during the GO/G1 phase. Two strategies are used to demonstrate the direct involvement of the nm23.h1 gene in the process of cell proliferation. The first consists of transient inhibition of nm23.h1 expression by using anti-sense oligonucleotide treatment; weak inhibitory effect on cell proliferation is observed. The second strategy involves the stable inhibition of nm23.h1 expression by transfection of MCF1OA cells with a plasmid vector expressing the human nm23.h1 anti-sense mRNA. The anti-sense-transfected cells show consistently slower proliferative activity than the control.

Enriched SSCP: a highly sensitive method for the detection of unknown mutations. Application to the molecular diagnosis of lung cancer in sputum samples

Detection of gene mutations by sensitive polymerase chain reaction (PCR)-based methods can allow to identify occult neoplastic cells in a great excess of nonmalignant cells. These molecular approaches have an enormous potential in terms of early diagnosis, detection of occult micrometastases of solid tumors, and minimal residual disease in patients with hematopoietic malignancies. Currently, the applications of such methods are limited, mainly because the high sensitivity required for the identification of rare mutated alleles can be achieved only in cases in which mutations occur in few specific codons of a gene or when the mutation is already known. No methods are available by which few alleles with unknown mutations in tumor genes can be recognized in a great excess of wild-type alleles. We have developed an extremely sensitive method, termed enriched single-strand conformational polymorphism (E-SSCP), which permits detection of a rare alleles with unknown mutations. The method is based on the observation that after a conventional SSCP analysis the vast majority of mutated bands migrate close to the wild-type bands. The area of the gel having the highest chance to hold mutated alleles is physically isolated and is used as substrate for a second round of SSCP. Serially diluted DNA samples containing gene mutations demonstrated detection of 1 mutant/10(6) normal alleles. The E-SSCP assay was first applied to six sputum samples of patients affected by lung cancers with known p53 mutations showing in sputa the same mutations observed in tumors. The technique was then applied to eight cytologically negative sputum samples obtained from patients who later developed a clinically manifested lung carcinoma. In three cases, harboring a p53 mutation in tumor tissue, the E-SSCP analysis allowed the detection of the mutations in sputa months before clinical diagnosis. In conclusion, we have presented a general, highly sensitive technique for the detection of unknown mutations that may have several potential applications and may hold considerable promise for the early detection and study of cancer.

Defective interleukin six expression and responsiveness in human mammary cells transformed by an adeno 5/SV40 hybrid virus

Mammary epithelial cells (MECs) were isolated and cultured from mammary glands of healthy women undergoing reduction mammoplasty. Normal MECs were infected with the transforming hybrid virus adeno-5/SV40. Two transformed epithelial cell lines, M1 and M2, were obtained, characterised phenotypically and studied for the production of and the response to cytokines and growth regulators. In both cell lines, expression of the SV40 large T antigen was associated with loss of interleukin 6 (IL-6) production and responsiveness as well as with down-regulation of IL-8 and transforming growth factor (TGF)-alpha production. Both M1 and M2 cell lines were capable of forming colonies in semisolid media, but upon injection into severe combined immunodeficient (SCID) mice only M2 cells were tumorigenic. DNA synthesis in M1 cells was partially inhibited by serum or TNF-alpha and weakly stimulated by hydrocortisone (HC) and IL-8. In contrast, M2 cells were totally unresponsive to a variety of growth regulators. Both lines overexpressed the p53 protein at levels about 20-fold higher than those observed in primary MEC cultures, but no mutations of the p53 gene could be detected. The date confirm the view that the expression in human mammary cells of different oncogenes - including the SV40 T antigen - is frequently associated with alterations of cytokine production and responsiveness.

p21 RNA and protein expression in non-small cell lung carcinomas: evidence of p53-independent expression and association with tumoral differentiation

p21, the product of the WAF1/CIP1/SDI1/mda-6 gene, is an inhibitor of cyclin-dependent kinases. In cell cultures p21 is induced by p53-dependent and p53-independent pathways by DNA damage and induction of differentiation. We investigated p21 RNA and immunohistochemical expression in 43 non-small cell lung carcinomas and corresponding normal lung samples previously investigated for p53 and WAF1 gene status and p53 protein expression. p21 RNA and protein expression in normal and neoplastic tissues were strictly associated (p-0.0001). In normal tissue p21 RNA was expressed at low levels and p21 immunoreactivity was seen in scattered differentiated bronchial, alveolar and stromal cells. In the majority of neoplasms p21 protein and RNA were expressed at higher levels than in the corresponding normal tissues: p21 overexpression was seen in 27 (63%) and 28 (65%) cases respectively. p21 was expressed independently from p53 gene/protein alterations. p21 overexpression was more frequent in well differentiated tumors (P=0.01 and P=0.022 for RNA and protein respectively), and p21 immunoreactivity was usually seen in foci of more pronounced differentiation. We conclude that p21 expression is related to tumor differentiation, and that p53-independent p21 expression is a common feature of in vivo neoplasms.

Point mutation of the autophosphorylation site or in the nuclear location signal causes protein kinase A RII beta regulatory subunit to lose its ability to revert transformed fibroblasts

The RII beta regulatory subunit of cAMP-dependent protein kinase (PKA) contains an autophosphorylation site and a nuclear location signal, KKRK. We approached the structure-function analysis of RII beta by using site-directed mutagenesis. Ser114 (the autophosphorylation site) of human RII beta was replaced with Ala (RII beta-P) or Arg264 of KKRK was replaced with Met (RII beta-K). ras-transformed NIH 3T3 (DT) cells were transfected with expression vectors for RII beta, RII beta-P, and RII beta-K, and the effects on PKA isozyme distribution and transformation properties were analyzed. DT cells contained PKA-I and PKA-II isozymes in a 1:2 ratio. Over-expression of wild-type or mutant RII beta resulted in an increase in PKA-II and the elimination of PKA-I. Only wild-type RII beta cells demonstrated inhibition of both anchorage-dependent and -independent growth and phenotypic change. The growth inhibitory effect of RII beta overexpression was not due to suppression of ras expression but was correlated with nuclear accumulation of RII beta. DT cells demonstrated growth inhibition and phenotypic change upon treatment with 8-Cl-cAMP. RII beta-P or RII beta-K cells failed to respond to 8-Cl-cAMP. These data suggest that autophosphorylation and nuclear location signal sequences are integral parts of the growth regulatory mechanism of RII beta.

mdm2 gene amplification and overexpression in non-small cell lung carcinomas with accumulation of the p53 protein in the absence of p53 gene mutations

Fifty-three non-small cell lung carcinomas (NSCLC), previously investigated for p53 abnormalities, were studied to evaluate the status of the mdm2 gene by Southern and Northern blot analysis and expression of the mdm2 protein by immunohistochemistry with specific monoclonal antibodies. Amplification and overexpression of the mdm2 gene and nuclear accumulation of its protein product were observed in three (6%) of the NSCLC examined. All of the tumors having mdm2 abnormalities belonged to a subset of NSCLC characterized by a strong accumulation of the p53 protein in the absence of p53 gene mutations. Since mdm2 is capable of forming tight complexes with p53, possibly stabilizing it, our results suggest that this event may take place in a low percentage of NSCLC. Moreover, all of the mdm2-positive tumors were histologically classified as lung adenocarcinomas. This may indicate that the mdm2 gene is preferentially altered in this particular subtype of lung tumors.

Cooperation between mutant p53 and the ras, raf, erbb-2 and fgf-3 oncogenes for transformation of mammary epithelial-cells

The murine mammary epithelial cells HC11 were used as a model to examine cooperation between mutated p53 and activated oncogenes for cell growth and transformation. These cells lack wild-type (wt) p53 and their proliferation in monolayer is inhibited by reitroduction of wt p53. Expression of the ras, raf, erbB-2 and fgf-3 (former int-2) oncogenes in HC11 cells leads to their growth in soft-agar, a parameter of cell transformation. Clonogenicity in soft-agar of the ras, raf and erbB-2 transformed cells was inhibited by a temperature-sensitive (ts) p53 at 32 degrees C, when the ts p53 protein is wt. Thus these oncogenes act synergistically with mutant p53 to induce anchorage-independent growth. Proliferation in monolayer of erbB-2, but not ras, raf, or fgf-3, transformed cells was retarded by ts p53 at 32 degrees C. Thus, ras, raf and fgf-3 oncogenes can partly or completely overcome the proliferation inhibitory function of wt p53, while erbB-2 cannot. These data indicate that specific oncogenes can distinctly cooperate with p53 for growth and transformation of mammary cells.

Retroviral vector-mediated overexpression of the RII beta subunit of the cAMP-dependent protein kinase induces differentiation in human leukemia cells and reverts the transformed phenotype of mouse fibroblasts

We have recently shown, using antisense strategy, that the RII beta regulatory subunit of cAMP-dependent protein kinase is essential for cAMP-induced growth inhibition and differentiation of HL-60 human leukemia cells. We constructed a retroviral vector for RII beta (MT-RII beta) by inserting human RII beta complementary DNA into the OT1521 retroviral vector plasmid that contains an internal mouse metallothionein-1 promoter and a neomycin resistance gene. The PA317 packaging cell line was then transfected with MT-RII beta plasmid to produce the amphotrophic stock of MT-RII beta retroviral vector. The infection with MT-RII beta and treatment with CdCl2 brought about growth arrest in HL-60 human leukemia and Ki-ras-transformed NIH 3T3 clone DT cells in monolayer culture with no sign of toxicity. The growth inhibition correlated with the expression of RII beta and accompanied changes in cell morphology; cells became flat, exhibiting enlarged cytoplasm. The growth of these cells in semisolid medium (anchorage-independent growth) was almost completely suppressed. In contrast, overexpression of the RI alpha subunit of protein kinase enhanced the cell proliferation in DT cells. The MT-RII beta-infected cells exhibited an increased sensitivity toward treatment with cAMP analogues, such as 8-Cl-cAMP and N6-benzyl-cAMP, as compared with the parental noninfected cells. In MT-RII beta HL-60 cells, N6-benzyl-cAMP treatment greatly enhanced the expression of monocytic surface markers. These results suggest that the RII beta cAMP receptor, by binding to its ligand, cAMP, acts as a tumor suppressor protein exerting growth inhibition, differentiation, and reverse transformation.

The effect of fgf-3 int-2 on growth and transformation of mcf-10a normal human mammary epithelial-cells is distinct from fgf-1 and fgf-2

Fibroblast growth factors (FGFs) are related polypeptides with mitogenic activity on cells of mesodermal and neuroectodermal origin. The Fgf-3 gene shares high homology with FGF-2 and its protein product can substitute FGF-2 as a growth factor. Other observations, however, indicate that Fgf-3 has specialized functions. We have investigated the effect of the expression and secretion of Fgf-3 on the growth and transformation of the human breast epithelial cell line MCF-10A. Overexpression of Fgf-3 stimulates proliferation of these cells in serum-free medium and induces anchorage-independent colony formation in soft agar. In contrast, these effects were not observed with purified FGF-1 and FGF-2 on either the parental or the Fgf-3-MCF-10A cells. Thus, Fgf-3 is distinct from FGF-1 and FGF-2 for its ability to induce cell proliferation and transformation of MCF-10A cells. This difference could be due, at least in part, to the expression of a specific set of FGF receptors with higher affinity for FGF-3 than FGF-1 or FGF-2.

Effects of mutant p53 genes on transformation of human mammary epithelial-cells

MCF-10A cells are a spontaneously immortalized, nontransformed human mammary epithelial cell line that contains two normal p53 alleles and produces a normal p53 protein. We have recently shown that overexpression of several genes that are important for normal mammary gland development and for neoplastic transformation, such as transforming growth factor alpha, c-Ha-rns or c-erbB-2, leads to in vitro transformation of these cells (Ciardiello et al: Mol Carcinogen 6: 43-52, 1992). To investigate the neoplastic potential of mutated forms of the p53 gene on MCF-10A cells, we have constructed two expression vector plasmids containing two p53 mutants that were isolated from human primary breast carcinomas. Overexpression of either mutant p53 gene confers on MCF-10A cells the ability to grow in serum-free medium in monolayer culture and to form colonies in semi-solid medium. Furthermore, to determine whether a mutated p53 gene may cooperate with a point mutated c-Ha-ras and/or the normal c-erbB-2 protooncogenes in the transformation of these cells, we generated clones of MCF-10A cells that overexpress a combination of these gene pruducts. Although these cells were able to grow with a higher cloning efficiency in soft agar, none of the cell lines was tumorigenic when injected subcutaneously into immunodeficient mice.

Expression of transforming growth factor alpha, amphiregulin and cripto-1 in human breast carcinomas

The expression of three epidermal growth factor (EGF)-related peptides, transforming growth factor alpha (TGF-alpha), amphiregulin (AR) and cripto-1 (CR-1), was examined by immunocytochemistry (ICC) in 68 primary infiltrating ductal (IDCs) and infiltrating lobular breast carcinomas (ILCs), and in 23 adjacent non-involved human mammary tissue samples. Within the 68 IDC and ILC specimens, 54 (79%) expressed immunoreactive TGF-alpha, 52 (77%) expressed AR and 56 (82%) expressed CR-1. Cytoplasmic staining was observed with all of the antibodies, and this staining could be eliminated by preabsorption of the antibodies with the appropriate peptide immunogen. Cytoplasmic staining with all of the antibodies was confined to the carcinoma cells, since no specific immunoreactivity could be detected in the surrounding stromal or endothelial cells. In addition to cytoplasmic reactivity, the AR antibody also exhibited nuclear staining in a number of the carcinoma specimens. No significant correlations were found between the percentage of carcinoma cells that were positive for TGF-alpha, AR or CR-1 and oestrogen receptor status, axillary lymph node involvement, histological grade, tumour size, proliferative index, loss of heterozygosity on chromosome 17p or overall patient survival. However, a highly significant inverse correlation was observed between the average percentage of carcinoma cells that expressed AR in individual tumours and the presence of a point-mutated p53 gene. Likewise, a significantly higher percentage of tumour cells in the ILC group expressed AR as compared with the average percentage of tumour cells that expressed AR in the IDC group. Of the 23 adjacent, non-involved breast tissue samples, CR-1 could be detected by ICC in only three (13%), while TGF-alpha was found in six (26%) and AR in ten (43%) of the non-involved breast tissues. These data demonstrate that breast carcinomas express multiple EGF-related peptides and show that the differential expression of CR-1 in malignant breast epithelial cells may serve as a potential tumour marker for breast cancer.

p53 alterations in non-small cell lung cancers correlate with metastatic involvement of hilar and mediastinal lymph nodes

Alterations of p53 are one of the most common molecular changes found in all types of lung tumors, suggesting a crucial role for p53 in bronchial carcinogenesis. However, the prognostic significance of p53 abnormalities in lung cancer patients is still unclear. By using genetic and immunohistochemical methods we have found p53 alterations in 40 of 53 (75%) primary, resected non-small cell lung cancer. A strong association (P = 0.0015) was found between deletions on chromosome region 17p13.3 and p53 mutations suggesting that loss of the wild-type p53 allele might be necessary for tumorigenesis. Correlations to clinicopathological parameters showed that p53 alterations (structural aberration of the gene and/or nuclear accumulation of the protein) are significantly linked with metastatic involvement of hilar and mediastinal lymph nodes (P < 0.01). Since the latter are well established prognostic factors for non-small cell lung cancer, p53 aberrations may also be a predictor of tumor aggressiveness.

Definition of regions of the human genome affected by loss of heterozygosity in primary human breast tumors

We have undertaken a systematic study of primary human breast tumor DNA to identify and characterize frequently occurring somatic mutations. Loss of heterozygosity (LOH) has been the most frequent mutation in our panels of primary breast tumor DNA. It is currently thought that LOH reveals recessive mutations within the affected region of the genome. One goal of our studies has been to physically define the target genes revealed by LOH in primary breast tumors. We have focused our efforts on chromosome 17, finding five regions of the chromosome which are independently affected by LOH in breast tumors. Two apparent target loci are on chromosome 17p; one is the TP53 gene. The other is an as-yet undefined locus telomeric to the TP53 gene. Loss of expression of the nme1 gene on chromosome 17q in tumors was linked to patients with a poor prognosis (p = 0.018). Although a significant trend (p = 0.05) was found between LOH of the nme1 gene and loss of nme1 expression, no point mutations were found within the coding region of the nme1 gene by single strand conformational polymorphism (SSCP) or nucleotide sequence analysis. These and other results suggest to us that there may be potential tumor suppressor genes both centromeric and telomeric to the nme1 locus on chromosome 17q.

The int-2 gene product acts as a growth factor and substitutes for basic fibroblast growth factor in promoting the differentiation of a normal mouse mammary epithelial cell line

We have investigated the effect of basic fibroblast growth factor (bFGF) and the related int-2 gene on the growth, transformation, and differentiation of HC11 mouse mammary epithelial cells. We show that in HC11 cells infected with int-2 retroviral expression vectors, the int-2 protein can function as a bFGF-like growth factor in stimulating: (a) HC11 cell proliferation in monolayer, (b) anchorage-independent growth in soft agar, and (c) soft agar growth of the bFGF-responsive SW13 tumor cell line. These effects are observed irrespective of whether the int-2 protein is expressed in its wild-type form or is linked to a signal peptide. A candidate bFGF receptor, which is the product of the flg gene and which may recognize the int-2 protein, is expressed at high levels in HC11 cells. Following epidermal growth factor or bFGF priming and subsequent treatment with lactogenic hormones, all of the int-2 infected and the parental HC11 cells synthesize similar levels of beta-casein. However, the autocrine expression of int-2 in HC11 cells abrogates their requirement for either exogenous epidermal growth factor or bFGF priming. These data suggest that, in HC11 cells, the growth factor activity of the int-2 gene is indistinguishable from that of bFGF and does not interfere with the mammary cell differentiation program associated with lactogenesis.

Stromal influences on transformation of human mammary epithelial cells overexpressing c-myc and SV40T

The proto-oncogene c-myc and the oncogene SV40T, both of which have been implicated in the process of cellular immortalization in vitro, have been introduced via amphotropic retroviral expression vectors into the human mammary epithelial cell (HMEC) line 184A1N4 (A1N4). Two stable cell lines were established by growth in selective medium and were found to overexpress either c-myc (A1N4-myc) or SV40T antigen (A1N4-T). Neither the A1N4, A1N4-myc, or A1N4-T cells will grow in soft agar or form tumors in nude mice. However, A1N4-T or A1N4-myc cells, but not the parental A1N4 cells, form colonies in soft agar in response to either epidermal growth factor (EGF), transforming growth factor alpha (TGF alpha), or basic fibroblast growth factor (bFGF). Like EGF and TGF alpha, bFGF is moderately mitogenic for the anchorage-dependent growth (ADG) of all three cell lines. Further, co-cultivation of A1N4-T or A1N4-myc cells with primary diploid mammary fibroblasts can also induce the anchorage-independent growth (AIG) and stimulate the ADG of A1N4-T or A1N4-myc. In addition, conditioned medium obtained from these mammary fibroblasts also stimulated the AIG of the A1N4-T and A1N4-myc cells and was found to contain immunoreactive TGF alpha and bioactive FGF. The mammary fibroblasts express specific mRNA transcripts for bFGF and acidic FGF (aFGF). These results suggest that growth factors such as TFG alpha or FGF, which may be derived from the adjacent mammary stroma, might influence in a paracrine manner the phenotypic characteristics of a population of human mammary epithelial cells toward transformation.

Transforming growth factor-alpha messenger RNA localization in the developing adult rat and human mammary gland by in situ hybridization

Transforming growth factor-alpha (TGF alpha) has been implicated in the autocrine growth control of a number of different rodent and human tumor cells, including breast cancer cells. Although TGF alpha has been detected in a limited number of normal tissues, its distribution and physiological function in the mammary gland are relatively unknown. TGF alpha mRNA expression was detected by in situ hybridization with a labeled TGF alpha antisense RNA probe and quantitated by application of computer-assisted digital image processing in both the ductal and alveolar epithelial cells in the virgin rat and nulliparous and parous human mammary glands. During pregnancy and lactation, the level of TGF alpha mRNA expression in the ductal and alveolar epithelial cells increased two- to threefold, while a heterogeneous yet strong expression of TGF alpha mRNA could also be detected in approximately 10-15% of the surrounding stromal cells in the pregnant mammary gland.

Loss of heterozygosity of the L-myc oncogene in human breast tumors

Recent studies suggest that loss of heterozygosity may play an important role in various human neoplasia. Cytogenetic abnormalities detected in primary breast tumors led us to examine breast tumor DNAs for deletions. In the present study, we demonstrate, using restriction fragment length polymorphism (RFLP) analysis at the L-myc proto-oncogene (chromosome 1p32), a frequent loss of heterozygosity in primary breast tumor DNAs (55 out of 152 informative tumor DNAs). Most of these deletions appear to be limited to chromosome 1p. No correlation was observed between this genetic alteration and several parameters of each patient's history or characteristics of the tumor. However, a significantly (P = 0.011) shorter survival period after relapse was observed for patients with loss of heterozygosity at L-myc in primary tumor DNAs compared with patients with tumor DNAs lacking this alteration.

mRNA expression of transforming growth factor alpha in human breast carcinomas and its activity in effusions of breast cancer patients

Transforming growth factor alpha (TGF alpha) mRNA expression was measured by Northern blot analysis in 18 human, primary, infiltrating, ductal breast carcinomas. Expression of a 4.8-kilobase TGF alpha mRNA transcript was detected in nine of 18 tumors. No evidence was observed of any gross amplifications or major rearrangements of the TGF alpha gene in the breast carcinoma specimens. Biologically active and immunoreactive TGF alpha was measured in the pleural effusions or in the ascitic fluids from 37 noncancer and 63 cancer patients. The TGF alpha activity detected ranged from 0.2 to 26 ng/mL in most effusions from both groups. However, 29 of 63 (46%) of the effusions from cancer patients exhibited TGF alpha levels that were 6 ng/mL or higher, whereas only seven of 37 (19%) of those from noncancer patients exceeded this level (P less than .03). In particular, effusions obtained from breast cancer patients showed a significantly higher level of TGF alpha, compared with those from noncancer patients (P less than .001). Effusions from 14 cancer patients also contained elevated levels of two tumor-associated antigens, CEA and/or TAG-72, and within this group, nine also had elevated levels of TGF alpha.

In situ detection of c-myc mRNA in adenocarcinomas, adenomas, and mucosa of human colon

We used a sensitive RNA:RNA in situ hybridization technique to study steady-state levels of c-myc proto-oncogene mRNA in primary human colon adenocarcinomas, villous adenomas, and normal mucosa samples. Frozen tissue sections, fixed in 4% buffered paraformaldehyde, were hybridized to 35S-labeled anti-sense transcripts of a c-myc clone and processed for autoradiography. The specificity of the hybridization was controlled by using 35S-labeled plasmid transcripts as a negative control, while RNA preservation in the tissue sample was assessed by using 35S-labeled anti-sense transcripts of a murine 28S rRNA clone. c-myc RNA was detectable in all the carcinomas (eight) and villous adenomas (four), but steady-state levels varied from high to low in different tumors with similar histology. Low levels of c-myc RNA were detected in epithelial stem cells of some of the normal mucosa samples (five). No genetic alterations of the c-myc locus were found by Southern analysis of DNAs extracted from the carcinomas.

The amplification unit on chromosome 11q13 in aggressive primary human breast tumors entails the bcl-1, int-2 and hst loci

The int-2 gene, a member of the fibroblast growth factor (FGF) super-gene family, has previously been shown to be amplified in 16% of the 110 human breast tumors examined. In order to characterize the amplification unit containing the int-2 gene (chromosome 11q13), the same panel of breast tumors was screened for possible amplifications of other markers mapping between 11q11 and 11q24. Out of the eight additional genes analysed, simultaneous amplification of bcl-1 (11q13, a locus involved in hematopoietic malignancies) and hst (11q13, another member of the FGF family) was observed in 17/18 tumors with increased copy number of the int-2 gene. A single breast tumor showed amplification of int-2 oncogene only. Neither the bcl-1 nor the hst locus was individually amplified in any of the tumor DNAs examined.

Transformation of an established mouse mammary epithelial cell line following transfection with a human transforming growth factor alpha cDNA

To determine whether the enhanced expression of transforming growth factor alpha (TGF alpha) is sufficient to induce the neoplastic transformation of an immortalized population of mammary epithelial cells, we cotransfected NOG-8 cells, a cloned mouse mammary epithelial cell line, with a simian virus 40-human TGF alpha cDNA expression vector plasmid and a pSV2neo plasmid. After cotransfection, nine G418-resistant NOG-8 colonies were cloned and expanded. All clones were subsequently analyzed for TGF alpha mRNA expression by northern blot analysis, TGF alpha secretion, anchorage-dependent growth in serum-free medium, anchorage-independent growth in soft agar, and tumorigenicity in nude mice. Three TGF alpha-transfected NOG-8 clones expressed high levels of a specific TGF alpha mRNA, secreted elevated levels of TGF alpha into the culture medium (177-595 ng/10(8) cells/48 h), exhibited an enhanced growth rate, grew aggressively as colonies in soft agar, and formed undifferentiated, invasive carcinomas in nude mice. A neutralizing mouse monoclonal antibody generated against the low molecular weight human TGF alpha peptide was able to inhibit colony formation in soft agar by TGF alpha-transfected NOG-8 clones that produced high levels by TGF alpha. This inhibition suggested that TGF alpha acted through an external autocrine loop. NOG-8 cells and NOG-8 cells transfected with a pSV2neo plasmid alone secreted very low levels of TGF alpha, failed to grow as colonies in soft agar and did not form tumors in nude mice. These results demonstrate that overexpression of a human TGF alpha cDNA in immortalized, nontransformed mouse mammary epithelial cells can induce a transformed phenotype in vitro and can facilitate tumor formation in vivo.

Induction of transforming growth factor alpha expression in mouse mammary epithelial cells after transformation with a point-mutated c-Ha-ras protooncogene

NOG-8 ras cells are a normal mouse mammary epithelial cell line transfected with a plasmid containing a glucocorticoid-inducible mouse mammary tumor virus long terminal repeat linked to the activated c-Ha-ras protooncogene. After addition of dexamethasone, there is a rapid induction (within 1-3 h) of p21ras protein that is concomitant with a parallel induction of the c-Ha-ras specific mRNA. After 4-6 days of dexamethasone treatment, NOG-8 ras cells are able to grow as colonies in semisolid medium. Between 9 and 12 days of dexamethasone treatment, there is a 5- to 6-fold increase of transforming growth factor alpha (TGF alpha) activity in the conditioned medium from NOG-8 ras cells. A 60-65% reduction in epidermal growth factor cell surface receptors on NOG-8 ras cells also occurs during this time interval. A 3- to 4-fold increase of the expression of a specific TGF alpha mRNA can be detected within 2 days of dexamethasone treatment, preceding the increase in TGF alpha protein found in the conditioned medium. Exogenous TGF alpha is able to stimulate in a dose-dependent fashion the anchorage-dependent and anchorage-independent growth of NOG-8 ras cells to a level comparable to that observed in dexamethasone treated ras-transformed NOG-8 ras cells. These results suggest that the enhanced expression of TGF alpha after induction of an activated ras protooncogene may be necessary for the anchorage-independent growth and subsequent morphological changes and the enhanced growth rate observed in ras-transformed mammary epithelial cells.

Selective modulation of protein kinase isozymes by the site-selective analog 8-chloroadenosine 3',5'-cyclic monophosphate provides a biological means for control of human colon cancer cell growth

Differential expression of type I and type II cAMP-dependent protein kinase isozymes has been linked to growth regulation and differentiation. We examined the expression of protein kinase isozymes in the LS 174T human colon cancer cell line during 8-chloroadenosine 3',5'-cyclic monophosphate (8-Cl-cAMP)-induced growth inhibition. Two species of RII (the regulatory subunit of protein kinase type II) with apparent Mr 52,000 (RII52) and Mr 56,000 (RII56) and a single species of RI (the regulatory subunit of protein kinase type I) with Mr 48,000 were identified in the cancer cells. RI and both forms of RII were covalently labeled with 8-azidoadenosine 3',5'-cyclic [32P]monophosphate, and two anti-RII antibodies that exclusively recognize either RII52 or RII56 resolved two forms of the RII receptors. 8-Cl-cAMP treatment induced a decrease of RI and an increase of both RII52 and RII56 in the cytosols of cancer cells and rapid translocation (within 10 min) of RII52 from the cytosol to nucleus. 8-Cl-cAMP caused transcriptional activation of the RII52 receptor gene and inactivation of the RI receptor gene. It also exhibited high-affinity site-1-selective binding to the purified preparations of both RII receptor proteins. Thus, differential regulation of various forms of cAMP receptor proteins is involved in 8-Cl-cAMP-induced regulation of cancer cell growth, and nuclear translocation of RII52 receptor protein appears to be an early event in such differential regulation.

The treatment of fractures of the tibia by Ender nailing and functional bracing. Results in the first 50 consecutive cases

Between July 1983 and December 1986 50 fractures of the tibia were treated by osteosynthesis with two crossed Ender nails and plaster or functional bracing. There was only one case of pseudarthrosis; in 6 cases there was axial deviation not exceeding 5 degrees and shortening not exceeding 6 mm. In our opinion this procedure has many biological and mechanical advantages with a minimal risk of infection (none in our series). A plastic functional orthosis has proved to be particularly suitable as an adjunct to Ender nailing. Fractures of the leg so treated have in fact acquired sufficient mechanical stability to allow early walking.

In situ c-myc expression and genomic status of the c-myc locus in infiltrating ductal carcinomas of the breast

We have studied the expression of the c-myc protooncogene and the cycle-dependent histone 4 gene at the cellular level by RNA:RNA in situ hybridization in 18 primary breast ductal adenocarcinomas. These tumors have previously been examined by Southern and Northern blot analysis for the genomic status of c-myc and its expression, respectively (Escot et al., Proc. Natl. Acad. Sci. USA, 83: 4834-4838, 1986). Positive c-myc hybridization signals were associated with carcinoma cells in all cases, including tumors which had no apparent alterations of the c-myc locus. Steady-state levels of c-myc mRNA appeared heterogeneous in carcinomas with similar histology. High levels of hybridization were found in four of seven tumors with strong amplification of the c-myc locus. Similarly high levels of c-myc hybridization were detected in two of nine cases which had an apparently normal c-myc locus but comparatively low cellularity. In addition to carcinoma cells, dense clusters of infiltrating lymphocytes, present in three tumors, exhibited c-myc hybridization. The expression of the histone 4 gene failed to correlate with levels of c-myc expression. We conclude that in infiltrating ductal carcinomas: (a) the c-myc protooncogene is transcriptionally activated; (b) c-myc amplification is probably underestimated due to heterogeneous cellularity; (c) high-level c-myc amplification is related to high-level expression, but other unknown factors also may play a role; (d) differences in levels of c-myc expression may not only be attributed to differences in the growth fractions; and (e) c-myc mRNA in total RNA from biopsy samples may be contributed by infiltrating lymphocytes.

Possible role of plasminogen activator content of the palmar nodules in recurrence of Dupuytren's contracture

Increased amounts of plasminogen activator enzymes were found in the large Dupuytren's nodules in the so-called active phase of the disease. A prospective study in 15 patients who had operations investigated possible relationships between fibrinolytic capacity of the palmar nodules (assessed by the fibrin plate method) and the recurrence of contracture. There were substantial analogies and suggestive connections with the results of previous electron microscopic studies. Combined with the presence of myofibroblasts, the high increase of plasminogen activator enzymes in the fascial nodules may be regarded as a predictive marker for possible recurrence after surgical treatment of Dupuytren's contracture.

Enhanced expression of c-Ha-ras p21 in human stomach adenocarcinomas defined by immunoassays using monoclonal antibodies and in situ hybridization

Using c-Ha-, c-Ki-, and c-N-ras-specific probes in a RNA-RNA hybridization assay we found enhanced expression of c-Ha-ras protooncogene in stomach adenocarcinomas relative to nonneoplastic epithelium, whereas little or no transcription of either c-Ki- or c-N-ras was detected. Enhanced levels of c-Ha-ras RNA expression were detected in all of the adenocarcinomas examined. Hybridization with c-Ha-ras was also detected in nonneoplastic gastric epithelium adjacent to carcinoma, although the labeling was less intense than that of carcinoma cells. More extensive analysis of the c-Ha-ras p21 expression was then carried out in formalin-fixed, paraffin-embedded tissue sections and extracts from surgically resected stomach tissues using monoclonal antibodies (MAbs) RAP-5 and Y13-259. The data obtained from the immunohistochemical studies were consistent with the results of in situ hybridization assay. Adenocarcinomas were much more reactive with MAb RAP-5 than benign and normal tissues, and the majority of carcinomas demonstrated increased expression of c-Ha-ras p21. Quantitative liquid competition radioimmunoassays using MAb Y13-259 also demonstrated significantly higher levels of c-Ha-ras p21 in extracts from stomach adenocarcinomas than those from normal mucosae. No strict correlation was found between ras p21 expression and the degree of tumor differentiation or histological type. Although advanced carcinomas generally demonstrated higher levels of ras p21 than early carcinomas, no correlation among advanced carcinomas and ras p21 levels was observed in relation to depth of tumor invasion to the muscularis propria, subserosa, or serosa. Benign lesions, in comparison, were much less reactive with MAb RAP-5 than carcinomas. Among the benign lesions tested, dysplastic lesions were more reactive than nondysplastic lesions. Normal stomach mucosa was generally nonreactive with the exception of parietal cells. Our results indicate that transformation of the stomach mucosa from benign to malignant phenotype is associated with an increase in c-Ha-ras p21 expression.

Fibrin/fibrinogen and fibrinolytic activity of the palmar fascia in Dupuytren's contracture

Considering the proved interaction of fibrin with fibroblasts and the seemingly decisive role of structural and functional changes ("modulation") of these cells in the evolution of Dupuytren's contracture, research has been carried out in order to investigate the fibrinolytic capacity and the possible presence of fibrin/fibrinogen in the palmar fascia of subjects operated upon for Dupuytren's Disease. Fibrin/fibrinogen were detected by a direct immunofluorescence technique and fibrinolytic activity was assessed by a fibrin plate method. A remarkable decrease of fibrinolytic activity and the presence of fibrin/fibrinogen were observed in small nodules in the early stage of disease, whereas large nodules showed a high amount of plasminogen activator enzymes. Small nodules seem to form and increase by progressive adhesion of fibroblasts to the polymerizing fibrin, while high fibrinolytic activity of large nodules probably results from "modulation" of many fibroblasts into contractile myofibroblasts and could therefore be considered as a biochemical sign of the evolutionary phase of Dupuytren's contracture.

Increased plasminogen activator enzymes of the tunica vaginalis in long-standing idiopathic hydrocele

Previous research has shown increased fibrinolytic activity of the serous membranes as a reaction to stimuli that did not destroy their mesothelium. Large amounts of fluid remarkably stretch and chronically stimulate the tunica vaginalis in long-standing idiopathic hydrocele. For these reasons, a prospective controlled study was carried out in 30 male patients in order to investigate the possible alterations of the fibrinolytic capacity of this serosa by a method suitable for measuring plasminogen activator content of a single layer of cells. A possible role of plasminogen activator enzymes as a protective barrier against incidental absorption of fibrin/fibrinogen from the hydrocele fluid into vaginal tissues is considered.