Diagnosis and management of bone metastases

Bone metastases are a common feature of many cancers and patients with a previous history of cancer may present with bony symptoms to many different specialties. It is, however, easy to mistakenly diagnose secondary bone cancer in patients who have abnormal imaging, when the cause of the symptoms and the abnormal imaging results is benign disease. In this review, common diagnostic mistakes are described with examples of imaging of both benign and malignant bony disease. The relative risk of developing bone metastases in different cancers is discussed, as well as the rationale of different therapies for proven bony metastases, such as radiotherapy, bisphosphonate therapy, orthopaedic intervention and vertebroplasty.

Reversible infertility and Castleman's disease

Castleman's disease may cause systemic symptoms with biochemical and haematological disturbances (Featherstone et al. 1990). These usually resolve completely soon after surgical removal of the abnormal mass. We report two cases of infertility associated with the systemic disturbances of abdominal Castleman's disease. Both women conceived less than one year after removal of the 'tumour' and delivered normal infants.

Meta-analysis of sentinel node biopsy in ductal carcinoma in situ of the breast

BACKGROUND

The need for sentinel lymph node (SLN) biopsy in patients with a preoperative diagnosis of ductal carcinoma in situ (DCIS) is debated. Advocates recommend such biopsy based on a high incidence of SLN involvement in some series. Opponents discourage SLN biopsy based on a perceived low incidence of nodal involvement in this setting. These contradictory arguments are generally based on small studies. The present study is a meta-analysis of the reported data on the incidence of SLN metastasis in patients with DCIS.

METHODS

A search of electronic databases identified studies reporting the frequency of SLN metastases in DCIS. The random-effects method was used to combine data.

RESULTS

Twenty-two published series were included in the meta-analysis. The estimate for the incidence of SLN metastases in patients with a preoperative diagnosis of DCIS was 7.4 (95 per cent confidence interval (c.i.) 6.2 to 8.9) per cent compared with 3.7 (95 per cent c.i. 2.8 to 4.8) per cent in patients with a definitive (postoperative) diagnosis of DCIS alone. This was a significant difference with an odds ratio of 2.11 (95 per cent c.i. 1.15 to 2.93).

CONCLUSION

Patients with a preoperative diagnosis of DCIS should be considered for SLN biopsy.

Dominance hierarchy formation in juvenile crayfish procambarus clarkii

The formation of social dominance hierarchies was studied in groups of five juvenile crayfish, 1.3-1.8 cm in length. Animals were grouped together in a small, featureless aquarium after having lived in isolation for more than a month. The occurrence of each of four behavior patterns (‘attack’, ‘approach’, ‘retreat’ and ‘escape’) was recorded for each animal, together with the frequency of encounters and the frequency of wins and losses. The frequencies of wins and losses were used to calculate the relative dominance value of each animal in the group. High levels of fighting developed immediately upon grouping the animals, and a positive feedback relationship between attacking and winning enabled one animal in each group to emerge quickly as the superdominant. If that animal was the largest, it remained as the superdominant; otherwise, it was replaced as superdominant within the first few days by the largest animal. This form of dominance hierarchy, with one superdominant and four subordinates, persisted throughout the duration of the grouping. Fighting declined over the first hour and by 24 h had dropped to low levels. After the first day, approaches were used together with attacks, and retreats replaced escapes. Attack and approach were the behavior patterns displayed most frequently by animals with high dominance values, whereas retreat and escape were performed by animals of low dominance. All these trends continued to develop over the next 2 weeks as the number of agonistic encounters declined to a low level.

Imaging of the thorax in the management of germ cell testicular tumours

AIM

To evaluate role of chest computed tomography (CTC) and chest radiography (CXR) in management of patients with testicular germ cell tumours (GCT).

PATIENTS AND METHODS

An analysis was undertaken of staging and re-assessment CTC and CXR examinations performed on patients with GCT over a 4.5-year period. Data were obtained on clinical presentation, tumour histology, tumour marker levels and clinical course. Consensus review interpretation was combined with these data to obtain a 'standard of reference'. Sensitivity, specificity and predictive values were derived by comparison of original imaging reports to 'standard of reference'.

RESULTS

Six hundred and twenty-three CTC examinations on 207 patients with GCT were included. Intrathoracic metastases were identified in 1% of seminoma patients compared with 20% of non-seminoma (NSGCT) patients. CTC was more accurate than CXR in the detection of intrathoracic metastases at 0.97, 0.96-0.98 (95% CI) compared with 0.91, 0.89-0.93. The agreement between imaging techniques and the standard of reference (determined by Kappa statistic) was respectively 0.96 for CTC and 0.65 for CXR. In GCT patients undergoing re-assessment with both CXR and CTC, CXR never detected unknown intrathoracic metastatic disease. Abdominopelvic lymphadenopathy was associated with intrathoracic metastases (P < 0.001), however re-assessment CTC did identify intrathoracic metastases in 27 cases without concurrent abdominopelvic disease. CXR was negative in 19 of these.

CONCLUSION

Routine interval CXRs are unnecessary in NSGCT patients undergoing regular re-assessment CTC due to the low additional yield and limited effect on management. Re-assessment should still include CTC. In low risk, pure seminoma patients (abdominal CT and marker negative) re-assessment CTC can be safely avoided. Baseline CTC is advocated with CXR alone for re-assessment.

Effect of three different warm-up regimens on heat balance and oxygen consumption of thoroughbred horses

Horses were exercised at 105% of their maximal O2 uptake until fatigued after three different warm-up regimens (no warm-up, a light warm-up, and a warm-up until the central venous temperature was > 39.5 degrees C) to assess the effect of the warm-up on the various avenues of heat loss. Approximately 12.79, 15.10, and 18.40 MJ of heat were generated in response to the warm-up and exercise after the three different warm-up regimens, respectively. Of the heat generated, 17.5, 17.2, and 17.4% remained as stored heat after 20 min of active recovery. Heat loss from the respiratory system was 63.6, 33.7, and 40.3% of the heat produced during and after the three warm-up intensities, respectively. The balance of the heat loss was assumed to be via the evaporation of sweat. On this basis, the heat loss by sweating was 14.9, 49.1, and 42.3% of the heat produced during and after the three warm-up intensities, which represented evaporation of 0.8, 3.1, and 3.0 liters of sweat, respectively. O2 consumption during exercise and heart rates 20 min postexercise, after two of the warm-up regimens, was significantly lower than that after no prior warm-up.

p53 mutation and expression in lymphoma

Mutation and abnormal expression of p53 was studied in 38 lymphomas [five Hodgkin's disease and 33 non-Hodgkin's lymphoma (NHL)]. CM1 polyclonal antibody was used to detect overexpression of p53. Three missense mutations were characterised in three cases of NHL after screening exons 5-8 of p53 of all the tumours with single-strand conformation polymorphism (SSCP) analysis. Only two out of three tumours with a missense mutation showed abnormal expression of p53 as measured by CM1. Conversely, seven out of nine tumours with positive CM1 staining had no point mutation demonstrated. Overexpression of p53 in the cases of NHL occurred in three out of twenty four low-grade tumours and five out of nine high-grade tumours (Kiel classification). The results suggest that abnormalities of p53 are commoner in high-grade than low-grade NHL, and that positive immunocytochemistry cannot be used to determine which tumours have mutations of p53.

p53 mutation in the myelodysplastic syndromes

We have studied point mutations in exons 5-8 of the p53 gene in the myelodysplastic syndromes (MDS) by using polymerase chain reaction (PCR) single-strand conformation polymorphism (SSCP) analysis and direct nucleotide sequencing. The subtypes examined were: refractory anaemia (RA), refractory anaemia with ring sideroblasts (RARS), chronic myelomonocytic leukaemia (CMML), refractory anaemia with excess blasts (RAEB), refractory anaemia with excess blasts in transformation (RAEBt), and acute myeloid leukaemia (AML) which had evolved from MDS. 26 cases of MDS were studied. 12 of these were sequentially sampled but none changed its p53 status during the time of the study (18 months). Four mutations (one nonsense and three missense) were identified. Each case with a mutation was of an advanced MDS subtype, suggesting that p53 mutation in these diseases is a terminal genetic event in the process of leukaemogenesis. The nonsense mutation inserted a premature stop codon in a case of AML which had evolved from RAEB; this mutation has been reported before in both chronic myeloid leukaemia (CML) and Burkitt's lymphoma. The three missense mutations have not previously been reported in haematological malignancies.

Occult malignancy is associated with venous thrombosis unresponsive to adequate anticoagulation

The increased incidence of intravascular thrombosis and thromboembolic episodes in patients with malignant disease is well documented. There have, however, been only two reports of covert malignancy in patients who continue to extend their deep vein thrombosis despite apparently adequate anticoagulation. Three patients are described in whom venous thrombosis steadily worsened despite a prothrombin time of at least twice normal. None had either obvious predisposing factors to thromboembolism or a family history of thrombotic disease. Recognition of this phenomenon can be helpful in avoiding delay in diagnosing malignancy in young patients.

Gas-forming infections

A 89 year old woman was admitted with increasing confusion and difficulty in walking. Her left thigh was swollen, erythematous and had associated crepitus.

The thrombolytic effect of heat

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Significant telomere shortening in childhood leukemia

Telomere length was studied by Southern analysis in five cases of childhood acute leukemia. In four cases, the length of the telomere sequence of the blast phase cells was shortened as compared with that of the cells examined during remission. Study of telomere length during chemotherapy for hematologic malignancies may show rapidly dividing subpopulations of malignant cells and thereby guide further treatment needs. In addition, such loss of telomere sequence would give rise to chromosomal instability and could be one of the mechanisms of oncogene activation in acute leukemia.

Alcoholism, hyponatraemia and central neurological damage: more than pontine myelinolysis?

Three patients with alcoholism and severe hyponatraemia are described. Permanent neurological damage occurred in each case with cerebral, cerebellar or pontine damage from infarction or haemorrhage following correction of the biochemical disturbance. No patient developed Central Pontine Myelinolysis (CPM), the condition usually associated with profound hyponatraemia and its correction.

Hemiplegia--a rare complication of acute Epstein-Barr virus (EBV) infection

A 32-year-old male presented to hospital with a transient hemiplegia associated with a rash and systemic upset. He was found to have an acute Epstein-Barr virus (EBV) infection. Hemiplegia complicating glandular fever has been described but once previously.

Nitrosoureido nucleosides as potential inhibitors of nucleotide biosynthesis

Several nitrosoureido nucleosides (3a, 3b, 5a, 7a, 7c, and 10a) designed as inhibitors of enzymes that metabolize pyrimidine nucleotides have been prepared and their chemical and biological properties studied. The methylnitrosoureas 3a and 3b were not significantly cytotoxic to H.Ep.-2 and L1210 cells in vitro but showed moderate activity in the P388 mouse leukemia screen (79% ILS for 3a and 56% ILS for 3b). The (chloroethyl)nitrosoureas 7a and 7c inhibited proliferation of L1210 cells, were cytotoxic to H.Ep.-2 cells, and demonstrated good activity against P388 in vivo (135% ILS with one 30-day survivor for 7a and 191% ILS with two 30-day survivors for 7c). Overnight exposure of L1210 cells to 7a and 7c resulted in cell enlargement accompanied by cell lysis. Macromolecular synthesis in enlarged cells, particularly RNA and protein synthesis, was markedly increased relative to that in untreated control cells. The half-lives of each of the nitrosoureas in pH 7 buffer was determined and compared with biological activity.

Metabolism and metabolic effects of 2-azahypoxanthine and 2-azaadenosine

The metabolism and metabolic effects of 2-azahypoxanthine and 2-azaadenosine were studied to elucidate the biochemical basis for their known cytotoxicities. 2-Azaadenosine is a known substrate for adenosine kinase. That 2-azahypoxanthine is a substrate for hypoxanthine (guanine) phosphoribosyltransferase is shown by the observations that, in cell-free fractions from HEp-2 cells supplemented with 5-phosphoribosyl-1-pyrophosphate, 2-azahypoxanthine inhibited the conversion of hypoxanthine to IMP but not the conversion of adenine to AMP, and hypoxanthine, but not adenine, inhibited the conversion of 2-azahypoxanthine to 2-azaIMP. [8-14C]2-Azahypoxanthine was synthesized from [8-14C]hypoxanthine via [2-14C]-4-amino-5-imidazolecarboxamide. In HEp-2 cells in culture, the principal metabolite of [8-14C]-2-azahypoxanthine was 2-azaATP; there was no detectable 14C in deoxynucleotides or in DNA or RNA fractions. 2-Azaadenosine was much more toxic than 2-azahypoxanthine, and, when used in the presence of an adenosine deaminase inhibitor, 2'-deoxycoformycin, was converted in HEp-2 cells to 2-azaATP in amounts that exceeded those of ATP in control cells. The pool of ATP was reduced by as much as 75% as 2-azaATP accumulated. In a short-term experiment (4 hr), 2-azaadenosine selectively reduced the pools of adenine nucleotides, whereas 2-azahypoxanthine reduced the pools of guanine nucleotides selectively. Both 2-azahypoxanthine and 2-azaadenosine inhibited the incorporation of formate into purine nucleotides and were without effect on the conversion of thymidine and uridine to nucleotides. 2-Azahypoxanthine inhibited the incorporation of thymidine into macro-molecules but not that of uridine or leucine; 2-azaadenosine inhibited the incorporation of all three of these precursors non-selectively. 2-AzaIMP inhibited IMP dehydrogenase competitively with IMP (Ki = 66 microM). The difference in effects of 2-azahypoxanthine and 2-azaadenosine perhaps may be due to the production, from 2-azahypoxanthine but not from 2-azaadenosine + 2'-deoxycoformycin, of 2-azaIMP, which inhibits synthesis of guanine nucleotides and thereby results in inhibition of DNA synthesis. Specific sites of action for 2-azaadenosine are yet undefined.

Chemical properties and biological effects of 2-haloethyl sulfonates

Data for the alkylating activities, DNA cross-linking activities, and proliferation-inhibitory activities toward cultured L1210 cells for twenty-four 2-haloethyl sulfonates are reported. Previously reported activities against P388 leukemia in vivo are also presented to permit correlation of in vitro and in vivo properties. Since these compounds are believed to be 2-haloethylating agents, their properties and effects were compared with those of chlorozotocin, which is a recognized 2-chloroethylating agent. 2-Chloroethyl chloromethanesulfonate, which was the most effective compound against P388 leukemia, had a moderate level of alkylating activity and a low level of cross-linking activity, but it was quite active in inhibiting proliferation of cultured L1210 cells. Although its alkylating activity was about the same as that of chlorozotocin, it caused much less cross-linking of DNA. The in vitro tests were useful for gaining information relating structure to the individual properties, but results obtained for one of the properties might not be predictive of the relative values obtained for other properties nor for in vivo activity against P388 leukemia. These results indicate that additional experiments to define the mechanism of action of these agents are needed.

Mode of action of 2-amino-6-chloro-1-deazapurine

2-Amino-6-chloro-1-deazapurine is of interest as a purine analog with demonstrated in vivo activity against mouse leukemia L1210. That the active form of this agent is a nucleotide and that the nucleotide is formed by the action of hypoxanthine (guanine) phosphoribosyltransferase were shown by the facts that (a) L1210 cells deficient in hypoxanthine phosphoribosyltransferase were insensitive to the analog; (b) hypoxanthine, but not adenine, prevented the formation of the analog nucleotide by enzyme preparations containing activities of both hypoxanthine and adenine phosphoribosyltransferases; and (c) the cytotoxicity of the analog was prevented by hypoxanthine. The ribonucleoside of this analog was not toxic to cell cultures and hence is not phosphorylated or cleaved to the base. In intact HEp-2 cells and L1210 cells, the analog was metabolized to the nucleoside 5'-phosphate which accumulated to concentrations as high as 1000 nmoles/10(9) cells; no di- or triphosphates were detected. In HEp-2 cells, the analog reduced the pools of purine nucleotides with some accumulation of IMP. The toxicity of minimal inhibitory concentrations of the analog to HEp-2 cells could be prevented or reversed by 4(5)-amino-5(4)-imidazolecarboxamide (AIC); the toxicity of higher concentrations could be prevented or reversed by a combination of adenine and guanosine but not by AIC. The analog inhibited the incorporation of formate into purine nucleotides and into macromolecules at concentrations that had no effect on utilization of hypoxanthine; at higher concentrations the incorporation of hypoxanthine was inhibited. Low concentrations also inhibited the utilization of uridine and thymidine. The incorporation of hypoxanthine and AIC into guanine nucleotides, but not adenine nucleotides, was inhibited. These results indicate two sites of inhibition of the biosynthesis of purine nucleotides, the more sensitive one being on an early step of the pathway and the less sensitive one on the IMP-GMP conversion. That the blockade of de novo synthesis probably was at the site of feedback inhibition was indicated by the fact that the analog inhibited the accumulation of formylglycinamide ribonucleotide in azaserine-treated cells but did not inhibit the synthesis of 5'-phosphoribosyl 1-pyrophosphate. Comparative studies were performed with the related analog, 2-amino-6-chloropurine, which has been reported to produce a similar dual blockade of the purine pathway. This purine was less toxic than its 1-deaza analog; it produced a modest decrease in adenine nucleotides but increased pools of guanine nucleotides.(ABSTRACT TRUNCATED AT 400 WORDS)

Biological effects and structure-activity relationships of 1,2-dihydropyrido[3,4-b]pyrazines

The effects of a number of 1,2-dihydropyrido[3,4-b]pyrazines (1-deaza-7,8-dihydropteridines) upon the proliferation and the mitotic index of cultured L1210 cells and upon the survival of mice bearing P388 leukemia were determined. The 1,2-dihydrostructure and amino groups or masked amino groups at positions 5 and 7 were necessary for activity, and various substituents at positions 2 and 3 had considerable influence upon the activity. A number of these pyrazines had significant activity against i.p. P388 leukemia in mice, and several pyrazines were more active than the corresponding oxazines or thiazines in both the in vitro and the in vivo systems. The effects of the pyrazines upon the cultured cells were reversible, and the rate and degree of reversibility were influenced by the substituents at positions 2 and 3. Tests performed with two of the pyrazines yielded results that indicate that these compounds, like the known agent nocodazole, might compete with colchicine for binding to tubulin. Synergistic killing of cultured L1210 cells was obtained with combinations of one of the pyrazines and vincristine.

Inhibition of mitosis and anticancer activity against experimental neoplasms by ethyl 5-amino-1,2-dihydro-3-[(N-methylanilino)methyl]-pyrido[3,4-b]pyrazin-7-ylcarbamate (NSC 181928)

Ethyl 5-amino-1,2-dihydro-3-[N-methylanilino)methyl]pyrido[3,4-b]pyrazin-7-ylcarbamate (NSC 181928) is reported to be active against several experimental neoplasms. The experimental data obtained in the present study indicate that it causes the accumulation of cells at mitosis with both cultured cells and ascites cancer cells in vivo. This effect was observed with L1210, P388, colon cancer 26, colon cancer 38, and H.Ep. 2 cells in culture and with L1210 cells and P388 cells in mice. The agent was also active in vitro and in vivo against a line of leukemia P388 cells that are resistant to vincristine.

Effects of N,N'-bis(2-chloroethyl)-N-nitrosourea and 2-[3-(2-chloroethyl)-3-nitrosoureido]-2-deoxy-D-glucopyranose upon the proliferation, DNA synthesis, and viability of cultured sensitive and resistant L1210 cells

The effects of N,N'-bis(2-chloroethyl)-N-nitrosourea and chlorozotocin upon the proliferation, DNA synthesis, and viability of cultured cells of a sensitive line of L1210 leukemia, a line partially resistant to N,N'-bis(2-chloroethyl)-N-nitrosourea, and a line resistant to cyclophosphamide were determined. The results indicate that neither the effect upon proliferation nor the effect upon DNA synthesis is a good predictor of the extent of cell kill. The similarity of the effects of N,N'-bis(2-chloroethyl)-N-nitrosourea upon these two parameters for the three cell lines indicates that the sensitive and resistant cells are affected to approximately the same extent, but more of the resistant cells survive. Additional studies are required to seek the reasons for this differential survival.

Mechanisms of action of 6-thioguanine, 6-mercaptopurine, and 8-azaguanine

The effects of 6-thioguanine on purine biosynthesis and cell viability have been examined in H.Ep. 2 cells grown in culture. Toxicity is not reversed by aminoimidazolecarboxamide, suggesting that inhibition of purine biosynthesis de novo is not the sole mechanism of toxicity. Also, 6-(methylmercapto)purine ribonucleoside, a potent inhibitor of purine biosynthesis de novo, produces more marked reductions in cellular pools of purines than does 6-thioguanine without killing cells. There is no apparent inhibition by 6-thioguanosine 5'-monophosphate of other enzymes leading to the synthesis of guanosine 5'-triphosphate as determined in whole cells by measurements of radioactive hypoxanthine or guanine incorporation. Inhibition of DNA synthesis by 1 mM thymidine protects cells from 6-mercaptopurine or 6-thioguanine but fails to protect cells from 8-azaguanine toxicity. On the other hand, inhibition of RNA synthesis by 6-azauridine plus deoxycytidine protects cells against 8-azaguanine but does not protect against 6-thioguanine or 6-mercaptopurine toxicity. In agreement with the in vitro data, arabinosylcytosine (a potent inhibitor of DNA synthesis) fails to protect mice against 8-azaguanine but has previously been shown to protect mice from 6-mercaptopurine or 6-thioguanine toxicity. The results support the hypotheses of others that incorporation into DNA (as 6-thioguanine nucleotide) is a mechanism of toxicity for these thiopurines, whereas 8-azaguanine is toxic due to its incorporation into RNA.