Case-referent survey of young adults with mesothelioma: I. Lung fibre analyses.

OBJECTIVES: Our study aimed to determine the lung tissue concentration of asbestos and other mineral fibres by type and length in persons with mesothelioma aged 50 yr or less at time of diagnosis, compared to controls of similar age and geographical region. In this age group it was thought that most, but not all, work-related exposures would have been since 1970, when the importation of crocidolite, but not amosite, was virtually eliminated. METHODS: Eligible cases were sought from recent reports by chest physicians to the SWORD occupational disease surveillance scheme. Lung tissue samples were obtained at autopsy from 69 male and four female cases, and mineral fibres identified, sized and counted by electron microscopy. Fibre concentrations per microg dry tissue were compared with similar estimates from a control series of autopsies of sudden or accidental deaths. Unadjusted, and adjusted odds ratios calculated by logistic regression, assessed relative risk in relation to fibre type, length and concentration. RESULTS: Unadjusted and adjusted odds ratios increased steadily with concentration of crocidolite, amosite, tremolite and all amphiboles combined. There was also some increase with chrysotile, but well short of statistical significance. Incremental risk examined in a linear model was as highly significant for all amphiboles together as individually. Short, medium and long amphibole fibres were all associated with increased risk in relation to length. Mullite and iron fibres were significant predictors of mesothelioma when considered without adjustment for confounding by amphiboles, but, after adjustment, were weak and far from statistically significant. CONCLUSIONS: In this young age group, amosite and crocidolite fibres could account for about 80% of cases of mesothelioma, and tremolite for some 7%. The contribution of chrysotile, because of low biopersistence, cannot be reliably assessed at autopsy, but to the extent that tremolite is a valid marker, our results suggest that it was small. The steep linear trend in odds ratio shown by amphiboles combined indicates that their effects may be additive, with increased risk from the lowest detectable fibre level. Non-asbestos mineral fibres probably made no contribution to this disease. Contrary to expectation, however, some 90% of cases were in men who had started work before 1970; this was so whether or not amosite or crocidolite was found in lung tissue.

Case-referent survey of young adults with mesothelioma: II. Occupational analyses.

OBJECTIVES: Our study aimed to identify occupations at increased risk of developing mesothelioma in persons aged 50 yr or less, and to relate these occupations to lung tissue concentration of asbestos fibres by type. In this age group it was thought that most, but not all, work-related exposures would have been since 1970, when the importation of crocidolite, but not amosite, was virtually eliminated. METHODS: Eligible cases were sought from recent reports by chest physicians to the SWORD occupational disease surveillance scheme. Work histories were obtained for 115 men and 13 women, usually with the help of the chest physicians or coroners. Jobs were coded by the Office of National Statistics, so that the observed years spent in each occupation could be compared with expected values from census data, 1960-90. Lung tissue samples were obtained at autopsy from 69 male and four female cases, and mineral fibres identified, sized and counted by electron microscopy. RESULTS: Of 37 industrial occupations analysed, odds ratios were significantly raised in eight: five in the construction industry and the others in shipbuilding, the manufacture of cement products and the manufacture of non-metallic mineral products (including asbestos). The concentrations in lung of crocidolite and amosite fibres, which together could account for 80-90% of cases, did not differ between occupational categories; those for amosite were appreciably higher than for crocidolite. Tremolite fibres were rarely found. CONCLUSION: Mesothelioma in this young age group is dominated by carpenters, plumbers, electricians and insulators in the construction industry, and is mainly attributable to amphibole exposure. Work in shipbuilding and manufacture of mineral products was less important than in earlier studies. Contrary to expectation, however, some 90% of cases were in men who had started work before 1970.

History of the Food and Drug Administration's Total Diet Study (Part II), 1987-1993.

The Total Diet Studies conducted by the U.S. Food and Drug Administration (FDA) provide yearly information on levels of pesticide residues, contaminants, and nutrients in the food supply and diets of specific age-sex groups. They also identify trends and changes in the levels of these substances in the food supply and in diets over time. Results are useful in making policy decisions regarding the safety of the food supply, food additives, pesticide use, nutrient fortification, and food labeling. This paper provides information on studies performed by FDA from 1987 to 1993.

Reduced expression of hexokinase II in insulin-resistant diabetes.

The regulation of hexokinase II (HKII) was examined in fat and skeletal muscle of an animal model of non-insulin-dependent diabetes mellitus, the KKAY mouse. These tissues require insulin for facilitated transport of glucose and express the insulin-responsive transporter GLUT4. The combined data from two experiments (n = 12 for each experimental condition) demonstrated mean concentrations of plasma insulin in pmol/l and glucose in mmol/l of 122 and 7.2 (control nondiabetic C57 mouse) vs. 1,118 and 29.6 (diabetic mouse), respectively. The tissues of diabetic mice compared with control mice demonstrated a reduction of HKII mRNA abundance of 68% in epididymal fat (P = 0.0001) and 34% in the quadriceps muscles (P < 0.001), with concordant reduction in the abundance of GLUT4 mRNA of 60% in epididymal fat (P < 0.001). In comparison with the results in untreated diabetic mice, diabetic animals treated with the insulin-sensitizing drug pioglitazone demonstrated an increase in the abundance of HKII mRNA with a concordant increase of GLUT4 mRNA in epididymal fat (P = 0.03 and < 0.01, respectively), and an increase of HKII mRNA in the quadriceps muscles (P < 0.05). Separate experiments demonstrated a reduction of HKII protein abundance by 61% in epididymal fat (P < 0.001, n = 12 for each experimental condition) and by 71% in the quadriceps muscles (P < 0.001, n = 6 for each experimental condition). In comparison with untreated diabetic mice, there was an increase in the abundance of HKII protein in epididymal fat of animals treated with pioglitazone (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Pulmonary nodules due to reactive systemic amyloidosis (AA) in Crohn's disease.

Multiple nodules of AA (reactive systemic) amyloid were identified at necropsy in the lungs of a patient with Crohn's disease. No other organs were involved. Nodular pulmonary amyloidosis is usually caused by deposition of AL (primary) amyloid.

How reliable is the diagnosis of lung cancer using small biopsy specimens? Report of a UKCCCR Lung Cancer Working Party.

BACKGROUND: A study was undertaken to investigate the accuracy of typing of a series of bronchial carcinomas by experienced pathologists with an interest in lung cancer from the examination of bronchoscopic biopsy specimens. METHODS: Eighty bronchial biopsy specimens showing positive results for bronchial carcinoma were circulated to five pathologists, who recorded diagnostic criteria and diagnosis for each. Diagnoses were then compared with the diagnosis agreed from the resection specimen corresponding to each biopsy specimen. A "non-small cell carcinoma, not further specified" classification group was introduced for small biopsy specimens. RESULTS: A diagnostic accuracy of 75% was achieved for squamous cell carcinomas, 66% for small cell carcinomas, and 50% for adenocarcinomas. There was diagnostic confusion between small cell and non-small cell carcinoma in less than 10% of cases. The introduction of a non-specific non-small cell classification improved diagnostic accuracy by 10-15% for each non-small cell tumour group. CONCLUSIONS: There are appreciable inaccuracies in applying the World Health Organisation's 1981 classification of lung cancer to the diagnosis of bronchial carcinoma from small biopsy specimens and these inaccuracies have been measured. They can be diminished by introducing a less specific "non-small cell" category for use with this sort of biopsy material. Care should be taken not to overinterpret small biopsy specimens in lung cancer.

Malignant change in dermatitis artefacta.

Dermatitis artefacta is a chronic skin lesion produced by self-trauma. Avoidance of further trauma, topical steroids and psychological therapy all play a part in the treatment of such lesions. Unresolved lesions may become large and disfiguring and subject to infection. We report a case of one such lesion in an elderly woman who persistently excoriated a cholecystectomy scar over 40 years. Malignant transformation occurred in a manner analogous to the neoplastic change observed in other types of chronic ulcer (Marjolin's ulcer). The squamous cell carcinoma presented with widespread metastases from which the patient eventually died. Recent literature concerning Marjolin's ulcers is reviewed and it is noted that this is the first reported case of death caused by malignant change in dermatitis artefacta.

Histopathological findings in oesophageal carcinoma with and without preoperative chemotherapy.

AIMS: To investigate the pathological effects of preoperative chemotherapy on oesophageal carcinoma. METHODS: Qualitative and quantitative changes in oesophageal carcinoma after preoperative chemotherapy were assessed by examination of biopsy specimens before treatment and resected specimens. RESULTS: Of 13 patients with adenocarcinoma treated with 5-fluorouracil, adriamycin, and mitomycin (FAM), nine showed minor histological changes compared with 14 control cases. All 12 patients with squamous carcinoma treated with preoperative mitomycin, ifosfamide, and cisplatin (MIC) showed noticeable histological changes when compared with the 13 control cases. Changes included complete ablation (n = 1) and partial regression (n = 5) of the tumour. A quantitative estimate of the proportion of tumour to stroma showed no difference between control adenocarcinomas and those treated with chemotherapy. There was, however, a significant reduction (p < 0.01) in the proportion of tumour to stroma in the treated squamous group compared with the controls. There was no relation between the degree of response in squamous carcinomas and the degree of differentiation of the tumour. Patients in which squamous carcinomas responded well, as assessed quantitatively, showed a tendency to better survival at one year. CONCLUSIONS: Histopathological changes attributable to chemotherapy can be observed in oesophageal carcinoma. The response of squamous carcinoma to MIC is histologically more evident than that of adenocarcinoma to FAM. A quantitative technique may be useful in assessing the effect of chemotherapy in oesophageal squamous carcinoma.

Treatment of insulin-resistant mice with the oral antidiabetic agent pioglitazone: evaluation of liver GLUT2 and phosphoenolpyruvate carboxykinase expression.

Obese KKAy insulin-resistant mice represent a model for the human syndrome of noninsulin-dependent diabetes mellitus. As such, the animals are hyperglycemic and hyperinsulinenic. Treatment of KKAy mice with pioglitazone, a new antihyperglycemic agent, lowered elevated blood glucose and insulin levels to near normal. Since hepatic glucose overproduction is a key abnormality in noninsulin-dependent diabetes mellitus, the aim of the present study was to define the specific effects of pioglitazone on hepatic glucose metabolism and release. To do so, we evaluated the expression of the major liver glucose transporter, GLUT2, and examined the activity and expression of the major rate-limiting enzyme for gluconeogenesis, phosphoenolpyruvate carboxykinase. Our results showed that GLUT2 mRNA abundance was unchanged in diabetic KKAy mice compared to nondiabetic animals, and that no changes were elicited by pioglitazone treatment. Such unaltered GLUT2 levels were consistent with a role for liver GLUT2 in bidirectional transport of glucose during physiological states of uptake or release. In contrast, phosphoenolpyruvate carboxykinase activity and mRNA abundance were concordantly elevated 2-fold in diabetic animals and were returned to normal levels after treatment with pioglitazone. Given that pioglitazone therapy led to decreased hepatic gluconeogenesis while insulin levels were concomitantly lowered, it appeared that pioglitazone acted to restore sensitivity to insulin's normal inhibitory actions.

Epithelial cell type, clinical behaviour and AgNOR counts in thymic epithelial tumours.

The relationship between epithelial cell type, clinical behaviour and number of nucleolar organiser regions (AgNORs) was investigated in 37 thymomas and three thymic carcinomas. The thymomas were classified according to epithelial cell morphology as cortical (16 cases), medullary (8 cases) or mixed (13 cases). Seven cortical tumours had infiltrated the capsule or adjacent structures at the time of operation, whereas only one medullary and two mixed tumours showed evidence of invasion, the differences being statistically significant (P less than 0.01). None of the patients with medullary thymoma had myasthenia gravis, but there was a significantly higher incidence (P less than 0.001) among those with cortical or mixed tumours (six and three cases respectively). The mean AgNOR count for medullary tumours was 1.56, compared with 2.22 and 2.06 for cortical and mixed tumours. Although the counts for medullary tumours were significantly lower than for the other two types (P less than 0.01), there was considerable overlap. The mean count for the carcinomas was 4.94--significantly higher than for the thymomas (P less than 0.01)--but again overlap was considerable. No relationship was demonstrable between AgNOR counts, clinical stage, incidence of myasthenia or recurrence. It is concluded that although classification of thymomas based on epithelial cell type represents an improvement on previous classifications, it must be applied with caution. Similarly, AgNOR counts may give some indication of malignant potential, but their usefulness in individual cases is doubtful.

Bacillus licheniformis APase I gene promoter: a strong well-regulated promoter in B. subtilis.

The 5' regulatory region and the portion of the structural gene coding for the amino-terminal sequence of alkaline phosphatase I (APase I) were isolated from Bacillus licheniformis MC14 using a synthetic oligodeoxynucleotide deduced from the amino acid sequence of the enzyme. The DNA sequence analysis of this region revealed an open reading frame of 129 amino acids containing the amino-terminal sequence of the mature APase protein. The protein sequence was preceded by a putative signal sequence of 32 amino acid residues. The predicted amino acid sequence of the partial APase clone as well as the experimentally determined amino acid sequence of the enzyme indicated that B. licheniformis APase retains the important features conserved among other APases of Bacillus subtilis, Escherichia coli, Saccharomyces cerevisiae, and various human tissues. Heterologous expression studies of the promoter using a fusion with the lacZ gene indicated that it functions as a very strong inducible promoter in B. subtilis that is tightly regulated by phosphate concentration.

Identification of four unique clones encoding 10 kDa proteins from Bacillus that cause phenotypic complementation of a phoA mutant strain of Escherichia coli.

A number of clones have been isolated from two Bacillus species which complement the PhoA- phenotype of Escherichia coli mutants under conditions that induce the expression of alkaline phosphatase (APase). These clones were initially thought to carry XPases because the transformed host could hydrolyse a common APase substrate, XP (5-bromo-4-chloro-3-indolyl-phosphate). The sequences of the open reading frames responsible for the phenotypic complementation showed no sequence similarity to ATPases of E. coli, human (bone-liver-kidney, intestinal or placental) or Bacillus. Therefore, these clones were designated as XPA (for X Phosphatase Activity) clones. Four of the clones encoded small (10 kDa), basic, hydrophobic proteins. Two of these, xpaB from B. subtilis 168 and xpaL2 from B. licheniformis MC14, shared 62% identity at both the DNA and the predicted amino acid sequence level. The fact that homologues from two Bacillus strains were cloned indicated that the screen was specific, but not for APase genes. It is clear that phenotypic complementation with cloned DNA from another genus does not ensure the identification of an APase gene. Possible mechanisms for the abnormal phenotypic complementation are discussed.

Bacillus subtilis alkaline phosphatases III and IV. Cloning, sequencing, and comparisons of deduced amino acid sequence with Escherichia coli alkaline phosphatase three-dimensional structure.

Bacillus subtilis has an alkaline phosphatase multigene family. Two members of this gene family, phoAIII and phoAIV, were cloned, taking advantage of in vitro constructed strains containing a plasmid insertion within one or the other of the structural genes. The DNA sequences of the two genes showed approximately 64% identity at the DNA level and 63% identity in the deduced primary amino acid sequences. The phoAIII and phoAIV genes code for predicted proteins of 47,149 and 45,935 Da, respectively. Comparison of the deduced primary amino acid sequence of the mature proteins with other sequenced alkaline phosphatases from Escherichia coli, yeast, and humans shows 25-30% identity. Based on the refined crystal structure of E. coli alkaline phosphatase, it appears that the active site and the core of the structure are retained in both Bacillus alkaline phosphatases. However, both proteins are truncated at the amino terminus compared with other mature alkaline phosphatases, three sizable surface loops of E. coli are deleted, and a minidomain is replaced with a larger domain in the model. Neither Bacillus alkaline phosphatase sequenced contains any cysteine residues, an amino acid implicated in intrachain disulfide bond formation in other alkaline phosphatases.

The Bacillus subtilis phoAIV gene: effects of in vitro inactivation on total alkaline phosphatase production.

A degenerative oligodeoxyribonucleotide probe deduced from the first 19 amino acids of the mature alkaline phosphatase IV (APase IV) protein was used to clone a DNA fragment internal to the coding region of the phoAIV gene of Bacillus subtilis. An insertional mutation was constructed in the phoAIV locus using the integrative plasmid, pJM103, containing the cloned DNA fragment. The strain with the interrupted phoAIV gene showed no detectable APase IV product on Western-blot analysis. The impact of the phoAIV interruption on total APase production in B. subtilis 168 was analyzed under both phosphate starvation and sporulation culturing conditions. The mutation in phoAIV reduced total APase-specific activity by 75% in phosphate-starved cells, and resulted in the elimination of a salt-extractable membrane APase, as well as the secreted APase IV. Analysis of this membrane APase indicated that it is a phoAIV gene product which is localized within the membrane fraction of the lysed cell and not secreted. There was no effect on the production of sporulation APase. The phoAIV::pJM103 insertion was mapped and determined to be located at approx. 73 degrees on the B. subtilis 360 degrees chromosome.

The Bacillus subtilis 168 alkaline phosphatase III gene: impact of a phoAIII mutation on total alkaline phosphatase synthesis.

The first alkaline phosphatase (APase) structural gene mutant of Bacillus subtilis 168 was constructed by using a clone identified by hybridization to a synthetic degenerative oligonucleotide. The design of the probe was based on the first 29 amino acids of the sequenced mature APase III protein, which had been isolated from the secreted fraction of vegetative, phosphate-starved cells. DNA sequencing of the clone revealed the first 80 amino acids of the APase III protein, including a typical procaryotic signal sequence of 32 amino acids preceding the start of the mature protein. The 29 amino acids encoded by the predicted open reading frame immediately following the signal sequence are identical to the first 29 amino acids of the sequenced mature protein. This region shows 80% identity to strand A of the beta sheet that is very well conserved in Escherichia coli and mammalian APases. A phoAIII structural mutant was constructed by insertional mutagenesis with a fragment internal to the coding region. The effects of this mutation on APase production in B. subtilis 168 were analyzed under both phosphate starvation and sporulation conditions. The mutation in APase III reduced the total vegetative APase specific activity by approximately 40% and sporulation APase specific activity by approximately 45%. An APase protein was isolated from sporulating cells at stage III and was identified as APase III by protein sequencing of the amino terminus and by its absence in the phoAIII mutant. The APase III gene has been mapped to approximately 50 degrees on the B. subtilis chromosome.

Origin and behaviour of emphysematous bullae.

Giant emphysematous bullae are believed to produce symptoms of pulmonary compression and collapse by containing gas under pressure that has been generated through valvular feeding airways. To examine this hypothesis, we have measured oxygen and carbon dioxide tensions (PO2, PCO2) in four patients and pressure within the bullae in three patients immediately before surgery. During spontaneous tidal respiration PO2 in the bulla was higher than arterial PO2 but did not rise as fast during the breathing of oxygen. The intra-bulla pressure during inspiration was negative (-5.5 to -19 cm H2O) and similar to pleural pressure in phase and degree. During intermittent positive pressure ventilation in two patients airway pressures were transmitted to the bulla with the development of a positive end expiratory pressure within the bulla. Histological examination of the walls of the bullae in the four patients and adjacent lung tissue in an additional patient failed to identify any valvular mechanism. The available information suggests that bullae develop after retraction and collapse of surrounding lung away from a region of weakness.

Pulmonary adenocarcinoma: review of 106 cases and proposed new classification.

The gross and microscopic appearances of 106 resected pulmonary adenocarcinomas were reviewed and correlated with postoperative survival. Instead of using an established classification based on histological pattern, the tumours were categorised by cellular morphology and site as either parenchymal adenocarcinoma (67%), bronchial adenocarcinoma (13%), or adenocarcinoma of uncertain origin (20%). Despite their pleomorphic appearance parenchymal adenocarcinomas should be regarded as a single entity, derived from multipotential cells of the distal airway; bronchial adenocarcinomas were generally, but not invariably, associated with short postoperative survival; those tumours that could not be reclassified on histological grounds were large adenocarcinomas consisting mainly of mucus cells. Tumours of this type carry a poor prognosis.