Quantitative assessment of a human carcinogenic potency for propylene oxide

The potential for causing carcinogenic and mutagenic effects is the main concern when assessing the risks associated with low-level exposures of humans to the industrially important epoxide, propylene oxide (PO). The available basic information used in estimation of carcinogenic risk has been reviewed. It is concluded that the published data from gavage studies in rodents are less appropriate and that observed cancer incidences from long-term inhalation should preferably be utilized for quantitative risk assessment. Furthermore, PO and ethylene oxide (EO) are directly acting alkylating agents which exhibit several similarities. Although data are less comprehensive for PO than for EO, PO appears to yield a rather uniform alkylation pattern in various tissues. Also, similarly to EO, PO is probably detoxified at a rate which does not vary widely in various mammalian species, including man. For these reasons, the surface-based extrapolation model for estimation of the human equivalent dose may not be appropriate, and the previously derived carcinogenic potency factors should be revised downward. Alternative risk estimates are provided. From the most relevant available studies, we propose a carcinogenic potency factor of 0.001 (mg/kg/day)-1 for PO in humans by inhalation.

Increased hip-fracture incidence in the county of Ostergötland, Sweden, 1940-1986, with forecasts up to the year 2000: an epidemiological study

The incidence of hip fractures in the county of Ostergötland in Sweden has increased dramatically from 1940 to 1986, mainly due to an increase in age-specific incidence of trochanteric fractures. The increase is most pronounced in people over 80 but is present even in age groups down to 50 years. If the age-specific incidence rates continue to increase, and the population of the elderly grows in accordance with the forecast, there will be 70% more hip fractures in the year 2000 than in 1985.

Multiple primary colorectal adenocarcinomas: cytometric DNA ploidy patterns and histopathologic features

The nuclear DNA distribution pattern was studied by means of image cytometry in 18 patients with synchronous and 7 patients with metachronous colorectal adenocarcinomas. About 80 percent of a total number of 53 carcinomas were found to consist of neoplastic cells where the nuclear DNA distribution pattern was of the aneuploid type. In 19 of the 25 patients, all carcinomas in the individual colon had identical nuclear DNA distribution patterns. Aneuploid tumors tended to appear more frequently in the sigmoid colon and the rectum than in the right colon. Carcinomas associated with an adenoma were more common in the rectum and in Dukes' A carcinomas. The results of cytometric assessments of the nuclear DNA ploidy pattern of the neoplastic cells in colorectal carcinomas have previously been found to be an independent prognostic variable. From the observations made in the present study, it is concluded that the cytometric DNA ploidy pattern of multiple primary colorectal carcinomas corresponds to that found in single carcinomas. The similarity between the two groups of cancer patients is also supported by conformity between histopathologic features and prognosis.

Nodular fasciitis and fibromatosis of the female breast simulating breast cancer. Case reports

One case of nodular fasciitis and one of fibromatosis of the female breast are reported. These rare lesions simulated breast cancer clinically and mammographically. Histological diagnosis was obtained by excision of the lesions. A literature search in three large databases gave only 4 reported cases of nodular fasciitis of the female breast, fibromatosis was relatively more common in this location.

On the mechanism of the hepatocarcinogenicity of peroxisome proliferators

The absence of a genotoxic action in the rat of several peroxisome proliferators (PP) has been confirmed by measuring gross degradation, unscheduled DNA-synthesis (UDS), as well as by measurement of single strand breaks using alkali unwinding in absence and presence of inhibitors of DNA-repair. Similar results were obtained even after drastically lowering the glutathione content of liver. Further, after oral administration of ciprofibrate, no potentiating effect was found in vivo on the generation of micronuclei in hepatocytes by ionizing radiation. The metabolically inert PP, perfluorooctanoic acid, was found to act as a promoter of liver tumors in the rat induced by diethylnitrosamine in an initiation-selection-promotion protocol. The results are discussed in light of available information concerning the mechanism of action of PPs.

Quantitation of protein A in human plasma is possible after heat inactivation of the samples

Quantitative determination of staphylococcal protein A in plasma is often hampered by the interaction between protein A and immunoglobulins. In human plasma, these interactions may not only involve the non-immune binding to the Fc or Fab regions of Ig but also antigen/antibody interaction by specific antibodies directed against protein A. In this paper we describe a method which can be used to quantitate nanogram amounts of protein A in the presence of human plasma. The ELISA used for the quantification of protein A is based on a double antibody solid-phase assay utilizing chicken anti-protein A as both capture and detector antibody. Protein A may be measured down to 5 ng/ml in plasma and 0.5 ng/ml in buffer. The plasma samples were heat-inactivated before analysis and this eliminated interference in the assay caused by interaction of protein A with an excess of immunoglobulins. This assay provides a reliable and convenient method for the detection and quantitation of soluble protein A in human plasma.

Extracorporeal immunoadsorption therapy on rats. In vivo depletion of specific antibodies

A technique for extracorporeal immunoadsorption of circulating specific antibodies from the plasma of rats is described. Catheterization of rats was performed using the carotid and the jugular blood vessels. The rats were treated non-anaesthetized. Blood was pumped continuously through a hollow-fibre plasma filter at a rate of 1.5 ml/min and plasma was separated and passed through an adsorbent column at a flow of 0.2 ml/min. The treated plasma was mixed with the blood cells before being returned to the rat. The column contained the antigen covalently linked to agarose beads. About three plasma volumes were treated during a period of 3 h and 30 min, which resulted in an antibody depletion of about 90-95%. The antibody levels returned to pre-adsorption levels after 4-5 days, or in some cases even exceeded the titres before treatment.

Peroxisome proliferation and modulation of rat liver carcinogenesis by 2,4-dichlorophenoxyacetic acid, 2,4,5-trichlorophenoxyacetic acid, perfluorooctanoic acid and nafenopin

Using an initiation--selection--promotion protocol for induction of liver tumors in Wistar rats, the modulating action of various peroxisome proliferators on neoplasia as well as on selected biochemical parameters was studied. After treatment with diethylnitrosamine (DEN), the animals were subsequently subjected to a selection procedure involving feeding of 2-acetylaminofluorene (2-AAF), and in the middle of the 2-AAF treatment, a single necrogenic dose of carbon tetrachloride. Following a recovery period, the rats were fed a diet containing 0.1% nafenopin (NAF), 0.015% perfluorooctanoic acid (PFOA), 0.05% 2,4-dichlorophenoxyacetic acid (2,4-D), 0.05% 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) or 0.05% phenobarbital (PB) as a positive control. When the animals were killed, 7 months after initiation, the incidence of hepatocellular carcinoma was 83, 33 and 16% in the animals treated with NAF, PFOA or 2,4,5-T respectively. No cancers were observed in controls, or in the 2,4,-D groups. In comparison with controls, NAF and PFOA caused a 60-and 24-fold increase inthe peroxisomal beta-oxidation of fatty acids respectively, but only about a 2-fold increase in the catalase activity, 2,4-D and/or 2,4,5-T were much less active in this respect, giving approximately a doubling in the rate of fatty acid oxidation. The specific activity of D-amino acid and glycolate oxidases were significantly depressed, whereas the urate oxidase levels were apparently unaffected by the NAF and PFOA treatment. The results suggest that the selective induction of peroxisomal fatty acid oxidation is consistent with the hypothesis that imbalance between H2O2 overproduction and its destruction could play a role in the modulation of hepatocarcinogenesis by peroxisome proliferators.

Immunologic basis for adverse reactions to radiographic contrast media

The lymphocyte transformation test (LTT) was used to elucidate whether certain side effects induced by radiographic contrast media have an immunologic etiology. Groups studied were: 8 patients who had previously experienced adverse reactions in association with urography, 6 patients who underwent urography without notable side reactions, 17 occupationally exposed nurses, and 9 unexposed controls. The lymphocytes from 2 hypersensitive patients and from 11 nurses exhibited a positive proliferative response to amidotrizoate. Five nurses who had shown a positive response, had a previous history of hypersensitivity reactions when handling contrast media, whereas the remaining 6 were free of symptoms. Amidotrizoate-specific memory cells were absent in patients who underwent urography without signs of hypersensitivity and in 7/9 of unexposed control subjects. Lymphocytes from patients sensitive to amidotrizoate cross-reacted to structurally related ionic contrast media while non-ionic contrast agents did not induce proliferation of the lymphocytes. Thus, ionic radiographic contrast agents have antigenic properties in man. Irradiated mixtures of radiographic contrast media and serum proteins were, in general, not effective in inducing an LTT response.

Lymphocyte transformation test for diagnosis of isothiazolinone allergy in man

The lymphocyte transformation test (LTT) has been used for evaluation of in vitro lymphocyte responses in 18 patients with dermatitis and positive patch tests to 200 ppm of a combination of 5-chloro-2-methylisothiazolinone and 28methylisothiazolinone (MCI) in nine patients with dermatitis unrelated to MCI and in seven subjects without skin diseases. Two workers sensitized by occupational exposure to a formulation containing 1,2-benzisothiazolin-3-one (BIT) were also studied. Lymphocytes from nine patch-test-positive patients proliferated vigorously to MCI in vitro. Lymphocytes from the remaining nine patients were not stimulated. Lymphocytes from two BIT-sensitized workers responded to BIT in vitro. The lymphocyte proliferation to isothiazolinones indicates the presence of memory cells in the patients' blood and confirms immunologic reaction to the inducing agent. To establish clinical relevance of LTT results, 12 MCI patch-test-positive patients underwent "use test" with lotion containing 15 ppm MCI. Four of five LTT-positive patients were use-test-positive, whereas seven of seven LTT-negative patients were use-test-negative. LTT-positive and lotion-positive patients responded to 100 ppm or lower concentrations of MCI on patch testing, whereas seven of eight LTT-negative and lotion-negative patients responded to 200 ppm only. In the case of MCI, proliferation was due to the chlorinated component, indicating that this part contains an allergenic epitope. Finally, MCI-specific lymphocyte proliferation was observed only in patients with MCI-positive skin test, but not in nine patients with dermatitis induced by other agents, or in seven subjects without skin diseases. Thus, the lymphocyte transformation test is able to distinguish between irritant and allergic skin responses. It may also be valuable in establishing the clinically relevant patch-test concentration of allergens with irritative properties.

An optimized assay of specific IgE antibodies to reactive dyes and studies of immunologic responses in exposed workers

Methods of assaying reactive dye-specific IgE antibodies were investigated with a RAST. Sera from three patients, occupationally exposed to a reactive dye, Remazol black B (Chemical Abstract registry number 17095-24-8), were used. Directly dyed disks, that is, disks without any carrier protein, resulted in poor and unreliable measures of specific IgE. In contrast, optimized preparation of conjugates between the dye and human serum albumin resulted in efficient binding of specific IgE. The patients' RAST results were strongly positive, whereas sera from 36 exposed workers but without symptoms and sera from unexposed subjects with high levels of total IgE were negative. The hapten and carrier specificity of the IgE antibodies was studied by direct RAST and RAST inhibition. In one patient, the antibodies were principally hapten specific, whereas another patient was found to have antibodies with a high degree of specificity to the carrier. The third patient's antibodies were intermediate between the other two patients' antibodies in this respect, suggesting that antibody specificity is dependent not only on the nature of the hapten but also on individual immune response factors. The study demonstrates that it is important to use an optimized preparation of dye-protein conjugates to elicit reliable results and a high degree of specific IgE binding in the RAST.

Clinical appearances in severe ischaemic colitis. Case report

Ischaemic colitis was not diagnosed until laparotomy in five cases. In two it was secondary to hypotension and multiple organ failure, in two it was atherosclerotic, and one had polycythemia vera. The diagnosis should always be considered in patients with abdominal distension--with or without diarrhoea and abdominal pain--so that treatment may be instituted before the onset of peritonitis.

Passive expiratory flow-volume recordings in immature newborn rabbits. Effect of surfactant replacement on the time constant of the respiratory system

Immature newborn rabbits with a gestational age of 27 days were paralyzed and kept in body plethysmographs. They were ventilated for 10 min with a tidal volume of approximately 10 ml/kg, with or without previous surfactant treatment via the airways. Tidal volumes and flow were recorded with a pneumotachograph connected to the body plethysmograph, and the expiratory time constant of the respiratory system (trs) was determined from flow-volume diagrams. The values of trs after 10 min were significantly higher in surfactant-treated animals than in controls (50 +/- 7 vs. 23 +/- 4 ms; p less than 0.002), indicating stabilization of the alveoli. There was also a close correlation between trs and the compliance values calculated from tidal volumes and ventilator pressure (r = 0.80; p less than 0.001), as well as between trs and the alveolar volume density in histological lung sections, determined by automated image analysis (r = 0.71; p less than 0.001).

Comparison of the mitogenic activities of streptococcal protein-G and staphylococcal protein-A on human mononuclear cells

In the present work we report data from experiments comparing the proliferative stimuli demonstrated by Streptococcal Protein-G and Staphylococcal Protein A on human peripheral blood mononuclear cells. Protein-G and Protein-A are presented to the cells in solution as well as linked to plastic or Sepharose beads, or incorporated within the cell wall of whole bacteria. The cellular response is measured by incorporation of 3H-thymidine in 72 hr cultures. The soluble and the immobilized forms of Protein-A, but not those of Protein-G, displayed high mitogenicity. Possible explanations for the absence of Protein-G induced mitogenicity are discussed.

Additional value of fine-needle aspiration biopsy in a mammographic screening trial

The Stockholm breast cancer screening trial used single-view mammography as the sole screening method. A majority (63 per cent) of the mammographic selected cases from the first two screening rounds had uncertain mammograms, coded as 3 on an ordinal scale from 1 to 5, where 1 and 2 are dismissed as normal mammograms and 5 stands for a typical cancer. In this group of uncertain mammograms 30 cases were malignant and 431 were non-malignant. The aim of this study was to examine whether surgical biopsy in this group could be replaced by fine-needle aspiration (FNA) biopsy, combined with the information from the mammogram and clinical examination, and whether this diagnostic strategy could select the malignant cases with a high sensitivity. FNA biopsy selected 25 of the 30 mammary carcinomas as definite malignancy or atypia, with a sensitivity of 83 per cent (95 per cent confidence interval: 69-96 per cent), and combined with the information from the mammogram and clinical examination 29 of the malignancies were selected with a sensitivity of 97 per cent (95 per cent confidence interval: 83-100 per cent). In 398 of 431 non-malignant cases the diagnosis was established with the triple diagnostic approach without needing a surgical biopsy. In a clinical follow-up study, up to 64 months after the first screening round, only one false negative case was found, included in the group of 30 malignancies described above. With this strategy the rate of negative surgical biopsies was reduced by 90 per cent in the group with uncertain mammograms and without considerably impairing the reliability of the results.

Diagnosis of pulmonary embolism based upon alveolar dead space analysis

Pulmonary embolism (PE) leads to an abnormal alveolar deadspace that is expired in synchrony with gas from normally perfused alveoli. This feature of PE separates it from pulmonary diseases affecting the airways, which are characterized by nonsynchronous emptying of compartments with an uneven ventilation/perfusion relationship. An analysis of the single breath test (SBT) for CO2, SBT-CO2, focusing on the late tidal expirate, was made in order to evaluate the feasibility to use the SBT-CO2 for the diagnosis of PE. The test was evaluated in 38 patients with suspected PE where pulmonary angiography showed that nine had PE and 29 did not. It was also tested in a reference population consisting of patients with normal lung function, obstructive lung disease and interstitial lung disease. Previously suggested gas exchange measurements for the diagnosis of PE, ie, the physiologic deadspace fraction, VDphys/VT, and the arterial-to-end-tidal CO2 gradient, P(a-E')CO2, were also evaluated in the groups. SBT-CO2 achieved a nearly complete separation between the patients with PE and those without. The other measurements, however, showed a substantial overlap between patients with PE and those with obstructive or interstitial lung disease. The SBT-CO2 is simple and potentially widely available and warrants further study as a routine technique for the diagnosis of PE.

Receptors for epidermal growth factor and sex steroid hormones in human colorectal carcinomas

Iodinated epidermal growth factor was used to identify its specific receptor in 32 human colorectal carcinomas. The receptor was found in 25% of the tumors with values between 6.9 - 104.0 fmoles/mg DNA. Receptors for estrogen and progesterone were detected in 45 and 25% of the tumors respectively. No correlation was observed between short term survival and content of receptors for sex steroid hormones. Four of the 8 patients with detectable levels of epidermal growth factor receptor had experienced relapse.

Non-palpable invasive breast carcinomas from the Stockholm screening project

Sixty-six non-palpable, invasive mammary adenocarcinomas from the Stockholm mammography screening project were studied with respect to histopathology. In 53 of these tumors estrogen receptor (ER) content was estimated and in 30 of them also the DNA distribution pattern. The tumors were predominantly of low or intermediate histological malignancy grade and ER-rich, whereas the distribution of DNA ploidy equalled that found in a non-selected tumor material. Only 2 tumors recurred during follow-up (median 51 months), indicating that non-palpable breast carcinomas represent a prognostically favourable subset in spite of a relatively high proportion of aneuploid tumors.

A novel approach to monoclonal antibody separation using high performance liquid affinity chromatography (HPLAC) with SelectiSpher-10 protein G

Protein G, a bacterial cell wall protein extracted from strains of Streptococci, has been employed as a ligand in high performance liquid affinity chromatography (HPLAC) for separation of monoclonal antibodies. Examples are given of rapid high-resolution separations of rat and mouse monoclonal antibodies belonging to various subclasses. In comparison with protein A chromatography, we were able to show superior binding characteristics for SelectiSpher-10 protein G columns under conditions of 'low' ionic strength (about 0.1 M) and neutral pH (pH approximately 7). The monoclonal antibodies were isolated in high purity (greater than 90%) and with good recovery of specific activity (80-100%). We believe that the HPLAC technology based on SelectiSpher-10 protein G is of potential value in the analysis and purification of monoclonal antibodies from various species and subclasses.

Chronic recurrent multifocal osteomyelitis in children. A roentgenologic and scintigraphic investigation

Thirty cases of chronic recurrent multifocal osteomyelitis have been reported in the literature. A radiologic evaluation of thirty-one additional cases, 25 of whom also underwent bone scintigraphy, is presented. Bone biopsy specimens were obtained in 16 patients. Most lesions were located in the metaphyses of the long bones adjacent to the physis and had a characteristic, probably pathognomonic appearance. Extension into the epiphyses was rare. Lesions in the vertebral bodies, clavicle and pelvis had possibly a less specific radiographic appearance. Lesions in short tubular bones were non-specific. Bone scintigraphy had a practical value in evaluating the global distribution of lesions including asymptomatic lesions and lesions in the spine or pelvis, the latter being somewhat hard to detect with conventional radiography. All biopsies showed acute, subacute or chronic unspecific osteomyelitis, sometimes mixed in the same lesion. Staining for bacteria and fungi was negative.