Phase I trial of murine monoclonal antibody L6 in combination with subcutaneous interleukin-2 in patients with advanced carcinoma of the breast, colorectum, and lung

PURPOSE

A phase I trial was undertaken to determine the toxicity and biologic effects of a combination of murine monoclonal antibody L6 (MoAb L6) plus subcutaneous (SC) interleukin-2 (IL-2).

PATIENTS AND METHODS

Fifteen patients with refractory adenocarcinoma (five breast, five lung, five colorectal), received L6 at 200 mg/m2 intravenously (IV) daily on days 1 to 7, followed by a 1-week rest period. IL-2 was given at either 2, 3, or 4.5 x 10(6) U/m2 daily doses times 4 days for a total duration of 3 weeks.

RESULTS

Side effects of L6 consisted of mild fever and chills along with a rash and serum sickness in one patient. One patient developed dyspnea and urticaria, that resolved with antihistamines. Maximum-tolerated dose (MTD) of SC IL-2 was 3 x 10(6) U/m2, with dose-limiting toxicities that consisted of grade 4 fatigue and dyspnea. Significant decreases in complement levels along with increases in absolute lymphocyte count and eosinophil count were observed. Mean antibody-dependent cellular cytotoxicity from mononuclear cells taken from patients who received IL-2 was elevated significantly compared with baseline in all patients independent of IL-2 dose (P less than .05). Serum IL-2 levels were elevated in 13 of 14 patients (range, 0.9 to 100 U/mL). Human antimouse antibody (HAMA) titers were elevated in nine of 14 (64%) patients who were tested between 3 and 8 weeks after L6 infusion. One patient with breast cancer had a transient mixed response, and one patient with colorectal cancer had a partial response.

CONCLUSIONS

L6 and SC IL-2 were well tolerated in the majority of patients when given in the outpatient setting. In view of the clinical efficacy of this combination, more phase II trials are warranted.

Expression of p53 and 17p allelic loss in colorectal carcinoma

Mutations in the p53 gene are the most common genetic changes in cancer thus far. Many p53 mutations result in a protein product having a prolonged half-life compared to wild-type p53. The mutant protein is frequently detectable immunohistochemically, whereas the wild-type p53 present in normal cells is not. We examined 90 colorectal carcinomas for increased expression of p53 using 3 p53 specific monoclonal antibodies, PAb1801, PAb421, and PAb240. Overall, 70% of the colorectal carcinomas stained for p53. Each tumor's DNA was also assessed for loss of heterozygosity on chromosome 17p, the location of the p53 gene. Of those tumors that reacted with the anti-p53 antibodies, 76% showed loss on chromosome 17p. Tumors with loss of heterozygosity on 17p generally stained with all 3 antibodies, whereas those without loss tended to stain with just one antibody, typically PAb240. Fifteen tumors were examined for the presence of specific p53 mutations. A total of 10 mutations were found, 6 were missense and 2 were deletions, and all but one of the tumors with missense mutations stained for p53.

Pattern of p53 gene mutations in breast cancers of women of the midwestern United States

BACKGROUND

Mutation in the p53 gene is the most common genetic lesion in human cancers. The pattern of mutation in the p53 gene differs among cancers and may be a useful epidemiological tool for identification of factors contributing to carcinogenesis.

PURPOSE

Our purpose was to determine if the pattern of p53 mutation in breast carcinomas in our population of women residing in the midwestern region of the United States is similar to the pattern of p53 mutation in breast cancers in patients from other regions of the United States and Europe and in other epithelial tumors.

METHODS

With a technique we recently developed for the analysis of p53 mutations in genomic DNA from tumor cell clusters in touch preparations of solid tumors, we sequenced exons 5-9 and adjacent splice junctions of the gene in 44 breast cancers. Cells from each tumor were also stained with three monoclonal antibodies which recognize different epitopes of the p53 protein.

RESULTS

We detected p53 mutations in 14 (32.6%) of 44 breast carcinomas. Only half of the mutations were missense changes. The other half included five microdeletions (three producing frame-shifts), one single-base substitution generating a stop codon, and one single-base substitution generating a splice junction abnormality. Nuclear expression of p53 antigen was present in eight of 44 cancers, including six with hemizygous missense mutations in the p53 gene.

CONCLUSIONS

The pattern of p53 mutations in our breast cancer population differs from that reported in breast cancer populations by other investigators in which most p53 mutations were missense. Among 14 mutations in our population, at least five drastically altered the structure of p53, suggesting that a recessive mechanism of inactivation of the p53 gene may be more common than in other populations.

IMPLICATIONS

Differences in the pattern of p53 mutation in breast cancers in Midwestern women and in breast cancers in other populations may reflect selection bias or small sample sizes currently available. However, our data are compatible with the possibility that an endogenous or exogenous factor influences p53 carcinogenesis in some women with breast cancer in the Midwest to a greater extent than in other regions of the United States and Europe.

Mycobacterial infection is an important infective complication in British Asian dialysis patients

To define the extent and nature of mycobacterial infection in patients on an adult dialysis unit whose catchment population contains a large proportion of non-Caucasian subjects, a retrospective survey of all new patients accepted onto our maintenance dialysis programme between January 1987 and December 1989 was carried out. Twenty-six Asian, 13 Afro-Caribbean, two Oriental and 170 Caucasian patients were accepted onto the dialysis programme in the three-year recruitment period. Eight of the 26 Asian patients, but none of the others, had developed mycobacterial infection by the end of December 1990. One patient had a cerebral tuberculoma with miliary mottling on chest X-ray, one pulmonary tuberculosis, one tuberculous adenitis and 5 tuberculous peritonitis (four due to Mycobacterium tuberculosis and one Mycobacterium kansasii). All the patients had been living in the UK for an average of 15 (range 6-24) years, with no known recent exposure to tuberculosis. Five patients are now alive and well, one developed malabsorption following M. kansasii peritonitis, but two with tuberculous peritonitis died before treatment could be instituted. Mycobacterial infections were associated with a high level of mortality and morbidity. No Asian patient developed mycobacterial infection during post-transplant immunosuppressive therapy in the study period, probably because of the routine anti-tuberculous chemoprophylaxis employed in this group of patients. The diagnosis of mycobacterial infection should be suspected when an Asian dialysis patient develops a pyrexia of unknown origin. It is likely, though not proven, that anti-tuberculous chemoprophylaxis might reduce this high incidence of tuberculous infection in Asian dialysis patients.

Pneumocystis carinii pneumonia: detection of parasites by immunofluorescence based on a monoclonal antibody

A monoclonal antibody-based immunofluorescence test for the detection of Pneumocystis carinii was evaluated in comparison with the conventional direct staining by Grocott's silver methenamine technique. A total of 254 respiratory samples from HIV positive and other immunocompromised patients were examined. Cysts were detected in 30 (12%) of samples using the monoclonal test, but only 15 (6%) positives were found using the Grocott method. There is need for a speedy and efficient test for detection of these organisms, and the monoclonal test was found to be more reliable, quicker and more sensitive than the Grocott technique.

Crescentic transformation in primary membranous glomerulonephritis

A 31 year old man first developed steroid-resistant idiopathic membranous glomerulonephritis in 1981. Stable normal renal function was maintained until August 1988 when he suffered a clinical relapse with heavy proteinuria and declining renal function. Immunosuppressive therapy with prednisolone and cyclophosphamide was instituted in an attempt to arrest this relapse. Despite this, he later developed acute renal failure with histological evidence of crescentic transformation of his nephritis. This unusual transformation was not associated with features of systemic vasculitis or positive anti-glomerular basement membrane and anti-neutrophil cytoplasmic antibodies.

Sensations during chest tube removal

Nurses prepare patients for chest tube removal, yet little has been written to indicate the sensations to be expected during this routine procedure. The sensations reported by patients and factors that could influence those sensations were examined in this study. The sample consisted of 36 patients after thoracic surgery (24 men and 12 women), all of whom were scheduled to have either a mediastinal or a pleural tube removed. They reported their sensations and the intensity of those sensations (using a 100 mm visual analog scale) within 15 minutes after tube removal. The most frequently reported sensation during chest tube removal was burning, followed by pain and pulling with mean intensities of 64, 62, and 45, respectively. Subjects reported having few sensations after the tube was removed with only five reporting soreness in the chest. The sensations and intensities did not differ for those who did and did not receive analgesia or for those having a pleural tube versus a mediastinal tube removed. The sensations were similar for the old and young subjects with younger subjects reporting higher intensities. Women reported pain more frequently than men, but the intensities of the sensations reported by men and women were not significantly different. The sensations reported during chest tube removal differ from those described in the literature and can be used to prepare patients more appropriately for chest tube removal.

Reserpine-induced post-receptor reduction in muscarinic-mediated airway smooth muscle contraction

Radioligand binding was conducted on airways of the rat and human, surgically subdivided into trachea, lung airways, and parenchyma. 3H-QNB bound uniformly to receptors in separate sections of the rat and human airway. Receptor densities generally were ranked: lung airways greater than trachea greater than parenchyma. Receptor subtypes were identified mostly by pirenzepine displacement of bound 3H-QNB. The rat trachea, and rat and human lung airways had a uniformly low affinity for pirenzepine while rat and human parenchyma demonstrated both high and low affinity pirenzepine binding. Inhibition of methacholine-stimulated smooth muscle contraction by the M1 receptor antagonist, pirenzepine, and M2 receptor antagonist, gallamine, was studied in rat trachea and bronchus in vitro. Schild plot pA2 values were compatible with low potency antagonism, thereby favoring the presence of M3 receptors at these smooth muscle sites. Reserpine treatment of rats (0.5 mg kg-1 day-1 for 7 days) produced a decrease in peak tension in response to methacholine without changing the muscarinic receptor character (Kd 3H-QNB), population density (Bmax in fmol mg-1 protein), or function (methacholine EC50). These results indicate that muscarinic receptor heterogeneity exists in the airway of both laboratory rat and man. While the muscarinic receptor subserving airway smooth muscle contraction appears to be the M3 subtype, decreased contractile responses to methacholine by trachea and bronchus from reserpine-treated rats were receptor independent.

The clinical wear of three posterior composites

The wear of three posterior composites and two amalgams was assessed clinically and measured on replica models. For the composite restorations abrasion was measured as the depth of enamel exposed at the cavity margin. Attrition was measured for all materials as the depth of surface wear determined by laser interfereometry. For the posterior composites the mean abrasion was: Clearfil 79.2 microns, Occlusin 175.9 microns and P-30 96.1 microns. The corresponding values for attrition were: 153.4 microns, 205.9 microns and 255.5 microns, respectively. The attrition of the two amalgams was: New True Dentalloy 120.8 microns, Solila Nova 115.3 microns. Therefore, attrition was greater than abrasion and the attrition of the three composites was greater than that of the two amalgams. Abrasion was affected by local factors, including the marginal contour of the restoration, whereas attrition was largely a function of the properties of the material itself. These findings indicate that composites should not be considered as a direct alternative to amalgam, especially in patients with high occlusal stress.

Clinical evaluation of three posterior composite and two amalgam restorative materials: 3-year results

The clinical performance of three posterior composites and two amalgams was evaluated over 3 years. Three hundred and nine composites and 200 amalgams were reviewed at the 3-year recall. The following parameters were assessed: fractures, gingival condition, interproximal contacts, marginal adaptation, staining and colour match. Although there was no significant difference in the overall failure rate between the two types of material, there was a significantly higher incidence of fracture in the amalgam restorations. The amalgam failures were exclusively mechanical, whereas those affecting composites also included failures that were more biological in nature. A significantly higher proportion of the Class II composites failed to achieve an adequate approximal contact, but this was not reflected in a more adverse gingival response. Colour match, surface and marginal stain varied significantly within the composite group and appeared to be material-related. Overall, the materials Occlusion and P-30 were considered to be performing adequately. The clinical handling, colour match and radiopacity of Clearfil Posterior were considered to be unsatisfactory.

Simulations of a fox-rabies epidemic on an island using space-time finite elements

The two-dimensional reaction diffusion equations for the spread of rabies in a logistically growing fox population are solved numerically. The method, based upon Galerkin's approach, uses space-time finite elements. The numerical model is shown, quantitatively, to possess the essential features of earlier one and two-dimensional models and to reproduce the values of field data accurately. A more realistic illustration of the use of the model, a study of the spread of rabies over the Isle of Anglesey, is then discussed.

Immunoglobulin heavy chain switch region gene polymorphisms in glomerulonephritis

Much evidence suggests that primary IgA nephropathy (IgAN) and idiopathic membranous nephropathy (MN) are immune complex mediated diseases. Moreover, genetic factors may play an important role in their pathogenesis. Recently, restriction fragment length polymorphisms (RFLPs) of the immunoglobulin heavy chain genes have been described which appear to associate with glomerulonephritis. We have studied RFLPs of the switch region of the IgM (S mu) and IgA1 (S alpha 1) heavy chain in MN and IgAN. DNA obtained from British Caucasoids with IgAN (N = 75), MN (N = 43), and normal controls (N = 73), was digested with the restriction enzyme Sac1, and studied using Southern blot techniques and hybridization with a 32P labelled DNA probe homologous to S mu. This probe detects RFLPs at the S mu and S alpha 1 loci. The genotypic and allelic frequencies of the S mu and S alpha 1 alleles in IgAN and MN was similar to normal controls. Caucasoid subjects with IgAN from Northern and Southern Europe (Finland and Italy, respectively) were also studied to determine whether an ethnic variation in genetic susceptibility to IgAN exists. The frequency of the S mu and S alpha 1 alleles was similar between the patient groups and their respective local healthy controls. These results do not support the recent findings of an association with RFLPs of the S mu and S alpha 1 loci in IgAN and MN, and suggest that the immunoglobulin heavy chain switch region genes are not important in conferring disease susceptibility to IgAN or MN.

Genetic mapping of a cloned sequence responsible for susceptibility to ecotropic murine leukemia viruses

A mouse cDNA that confers susceptibility to ecotropic murine leukemia viruses following transfection into human EJ cells has been cloned and sequenced. We show that this sequence is likely to be Rec-1, the chromosome 5 locus originally defined by studies with somatic cell hybrids as responsible for virus susceptibility, and provide a specific chromosomal map position for this locus by analysis of an interspecies backcross. This locus maps in the distal region of chromosome 5 and is thus not within the cluster of retrovirus-related genes near the centromere.

Fast (4-h) or slow (24-h) infusions of pamidronate disodium (aminohydroxypropylidene diphosphonate (APD)) as single shot treatment of hypercalcaemia

Twenty-five patients with hypercalcaemia (ionised calcium, 1.57 +/- 0.04 mM; total calcium, 3.33 +/- 0.06 mM) due to malignancy were randomised to receive pamidronate (1 mg/kg body wt.) by infusion over 4 h (12 patients) or 24 h (13 patients). Forced saline diuresis was not utilised. Two patients died within 24 h and were not included in the analysis. Both groups combined (n = 23) showed a decrease in ionised calcium to 1.44 +/- 0.04 mM by 2 days (P less than 0.05 vs. day 0). By 4 days there had been a further fall to 1.27 +/- 0.05 mM (P less than 0.05 vs. day 2) and 7 days after treatment ionised calcium was 1.19 +/- 0.05 mM (P less than 0.05 vs. day 4). Total calcium declined from 3.33 +/- 0.06 to 2.65 +/- 0.11 mM over 7 days (P less than 0.001). Separate analyses of the two groups showed that the fast (4-h) infusion led to an earlier reduction in calcium than did the 24-h infusion (P less than 0.02), although after 7 days there was little difference between the two groups (4 h, 1.18 +/- 0.09 mM; 24 h, 1.23 +/- 0.06 mM, n.s.). Hypercalcaemic symptoms (analogue rating scale) improved between each of the time intervals 0, 4 and 7 days (P less than 0.05) and did not differ between the two groups. We recommend a single 4-h infusion of pamidronate (1 mg/kg) as primary treatment for malignancy-induced hypercalcaemia.

Plasma 24,25-dihydroxyvitamin D3 concentrations in X-linked hypophosphatemic mice: studies using mass fragmentographic and radioreceptor assays

Previous studies have suggested that both plasma 24,25-dihydroxyvitamin D [24,25-(OH)2D] concentrations and renal 25-hydroxyvitamin D-24-hydroxylase activity are increased in mice with X-linked hypophosphatemia (Hyp mice). However, because the plasma levels of 24,25-(OH)2D seemed surprisingly high, we repeated these assays using two different techniques. Mass fragmentographic and radioreceptor assays were employed to compare the plasma concentrations of 25-hydroxyvitamin D (25-OHD) and 24,25-(OH)2D in normal mice with those in Hyp mice. These assays yielded 24,25-(OH)2D concentrations much lower than previously reported in mice (both normal and Hyp). The concentrations of 25-OHD3 and 24,25-(OH)2D3, determined by mass fragmentography, were lower in Hyp mice than in controls [25-OHD3, 9.7 +/- 0.4 versus 14.6 +/- 0.6 ng/ml, p less than 0.01; 24,25-(OH)2D3, 7.1 +/- 0.3 versus 10.4 +/- 0.4 ng/ml, p less than 0.01]. Plasma 25-OHD concentration was the main determinant of plasma 24,25-(OH)2D, and the ratio of 25-OHD3 to 24,25-(OH)2D3 obtained from mass fragmentographic measurements did not differ between the two groups (1.40 +/- 0.05 versus 1.36 +/- 0.03 ng/ml, NS in normal and Hyp groups, respectively). Separate measurement of plasma 25-OHD, 24,25-(OH)2D, and 25-OHD3-26,23-lactone by radioreceptor assay showed no difference between either plasma 24,25-(OH)2D, or the ratio of 25-OHD concentration to 24,25-(OH)2D concentration among Hyp and control animals. In neither study was plasma phosphate concentration related to the 25-OHD3:24,25-(OH)2D3 ratio.(ABSTRACT TRUNCATED AT 250 WORDS)

Pharmacokinetics of once daily intra-peritoneal aztreonam and vancomycin in the treatment of CAPD peritonitis

The pharmacokinetics of aztreonam and vancomycin were studied in six adult patients who developed peritonitis during Continuous Ambulatory Peritoneal Dialysis. Aztreonam 3 g was added to the first exchange in each 24 h period with vancomycin 500 mg on the first day and 250 mg on each subsequent day (provided the pre-dose serum vancomycin concentration was less than 10 mg/l) for a total of ten days. Aztreonam and vancomycin concentrations were measured in the serum and dialysate at 1, 2, 6, 12, 18 and 24 h after the initial dose and pre-dose on days 5 and 10. By the end of the ten day study all patients had recovered clinically and had a normal dialysate. For aztreonam, the mean peak serum concentration was 84.3 mg/l (range 59.6-102.8), the mean 24 h pre-dose serum concentration was 23.0 mg/l (range 8.6-39.2) and the mean 24 h pre-dose dialysate concentration was 15.5 mg/l (range 5.0-32.0). For vancomycin, the mean peak serum concentration was 10.2 mg/l (range 8.1-12.6), the mean 24 h pre-dose concentration was 5.5 mg/l (range 3.6-6.4), and the mean 24 h pre-dose dialysate concentration was 3.4 mg/l (range 2.4-4.6). In the treatment of CAPD peritonitis, once daily intra-peritoneal administration of aztreonam 3 g with vancomycin 500 mg initially and 250 mg on subsequent days (serum concentrations permitting) provides concentrations of antibiotic in both the serum and dialysate throughout the 24 h period in excess of the inhibitory concentrations of those organisms most frequently encountered in this condition.

Hypophosphatemia complicating bronchodilator therapy for acute severe asthma

Hypophosphatemia has been recently highlighted as a reversible cause of respiratory muscle hypocontractility and reduced tissue oxygen extraction in patients with chronic obstructive lung disease and asthma. To define the prevalence and mechanism of hypophosphatemia under these circumstances, we studied phosphate homeostasis in 22 patients with chronic asthma, who had been hospitalized for emergency bronchodilator therapy. Serum phosphate concentration was normal in all patients on presentation, and fell after the initiation of bronchodilator therapy. Twelve patients (54%) developed hypophosphatemia (serum phosphate, less than 0.8 mmol/L). Urinary phosphate level fell in parallel. A negative correlation was observed between serum phosphate and serum theophylline concentrations, and a positive correlation between serum and urinary phosphate concentrations. No correlation was found between serum phosphate and serum albumin or urea concentration. These data indicate that hypophosphatemia is a common metabolic abnormality during the emergency treatment of asthma. The underlying mechanism appears to be drug-induced phosphate flux from the extra-cellular to the intracellular space. We suggest that the serum phosphate level be monitored in patients undergoing emergency treatment of bronchospasm, particularly if a prolonged period of bronchodilator therapy is required or if respiratory muscle fatigue supervenes.

One-shot high-dose pamidronate disodium (APD): effective, simple treatment for hypercalcaemia in haematological malignancy

Fifteen patients with haematological malignancy and hypercalcaemia (mean +/- SEM calcium 3.44 +/- 0.14 mmol/l) received pamidronate (1 mg/kg) by infusion on 17 occasions (two patients were retreated 2 and 6 months after the first dose). After 4 days the plasma calcium had fallen to 2.84 +/- 0.14 mmol/l (P less than 0.001; n = 17), and in 10/17 episodes was less than 2.6 mmol/l. The mean fall was 0.61 mmol/l (95% confidence intervals 0.49-0.72 mmol/l). By 7 days a further decrease to 2.53 +/- 0.10 mmol/l had occurred, continuing to 2.38 +/- 0.11 mmol/l after 14 days. Plasma phosphate fell from 1.18 +/- 0.16 to 0.74 +/- 0.07 mmol/l at 7 days (P less than 0.001; n = 12). In 9 of the 17 episodes plasma creatinine initially exceeded 120 mumol/l (four of these greater than 300 mumol/l). This did not impair the response to pamidronate and there was no significant change in plasma creatinine following treatment. A single large dose of pamidronate was a simple, well-tolerated and very reliable treatment for hypercalcaemia complicating haematological malignancy, irrespective of renal function.

Disturbance of cerebral function by aluminium in haemodialysis patients without overt aluminium toxicity

The psychomotor function of 27 long-term haemodialysis patients with apparently normal cerebral function, who had only mildly raised serum aluminium (mean 59 [SEM 9] micrograms/l), was measured by means of a computerised version of the symbol digit coding test. Compared with those of control subjects matched for age and the patients' estimated premorbid IQ, the patients' response times were significantly longer (2.51 [0.10] vs 1.88 [0.05] s). Abnormalities were also detected in five other computerised tests of psychomotor function. The mean activity of erythrocyte dihydropteridine reductase (DHPR), which is inhibited by aluminium, rose during 3 months' desferrioxamine treatment in most of the 15 patients so treated. Although there was no relation between baseline psychomotor function and either indices of cumulative aluminium exposure or erythrocyte DHPR activity, changes in DHPR induced by desferrioxamine correlated with changes in psychomotor performance (r = 0.62). The flash-stimulated visual evoked potential (measured in 10 patients) was delayed (133.4 [2.4] ms), although the pattern-stimulated visual evoked potential remained normal (101.8 [3.2] ms). The difference between the visual evoked potentials stimulated by flash and pattern was significantly greater in the patients than in the controls (31.6 [4.3] vs 19.4 [2.4] ms) and was significantly related to the symbol digit coding response times and to the oral aluminium intake. The results suggest that much more rigorous exclusion of aluminium from the dialysate and diet of dialysis patients is necessary.

Pharmacological and metabolic interactions between ethanol and methyl n-butyl ketone, methyl isobutyl ketone, methyl ethyl ketone, or acetone in mice

Methyl n-butyl ketone (MnBK), methyl isobutyl ketone (MIBK), methyl ethyl ketone (MEK), and acetone are widely used industrial solvents to which certain groups of workers are exposed. Pharmacological and metabolic interactions between these solvents and ethanol were explored in male CD-1 mice. The effects of these solvents on the duration of ethanol-induced loss of righting reflex and on ethanol elimination in mice were studied. The solvents were dissolved in corn oil and injected intraperitoneally 30 min before ethanol 4 g/kg ip. The four solvents prolonged significantly the duration of ethanol-induced loss of righting reflex when given in the following doses (mmol/kg): MnBK, 3.75 and 5; MIBK, 5; MEK, 5 and 10, acetone, 20 and 40. This prolongation was dose related and increased as the dose of the solvent was increased. The concentrations of ethanol in blood or brain on return of the righting reflex were similar in solvent-treated and control animals, with the exception of the group of mice treated with 40 mmol/kg acetone in which the ethanol concentrations were significantly lower than in control animals. The mean elimination rate of ethanol was markedly reduced in mice treated with MnBK 5 mmol/kg, MEK 15 mmol/kg, and acetone 40 mmol/kg. All four solvents reduced the activity of mouse liver alcohol dehydrogenase in vitro. It is concluded that enhancement of the ethanol-induced loss of righting reflex by these solvents in mice is well correlated to reduced elimination rate of ethanol.

Posterior composites: evaluations without trials?

Clinical trials for the evaluation of restorative materials are time-consuming, expensive and often based on subjectively assessed criteria. By the conclusion of a clinical trial materials are often obsolete. A DHSS-commissioned programme at the Liverpool School of Dentistry is in progress where clinical and laboratory evaluations of materials are being carried out in parallel with a view to correlating the results. The structure and scope of the programme is discussed and the value of establishing short-term laboratory tests predictive of clinical performance is considered. Preliminary observations emerging from the programme are discussed.

Effect of direction and rate of change of calcium on parathyroid hormone secretion in uraemia

We have studied the control of amino-terminal parathyroid hormone (PTH) secretion in haemodialysis patients in response to slow or fast calcium infusion and during acute hypocalcaemia. In nine patients, fast calcium infusion (0.4 mmol/kg bodyweight per hour) for 15 min increased ionised calcium and reduced PTH, with an initial t 1/2 of 12.8 min. After the infusion had ceased, calcium decreased steadily, and PTH increased, mean PTH reaching baseline values when calcium was still significantly greater than pre-infusion values. During slow calcium infusion for 2.5 h (0.1 mmol/kg bodyweight per hour), parathyroid suppression was evident at 15 min, when the calcium increment was only 0.03 mM. After 60 min, PTH did not decrease further despite progressive hypercalcaemia. Hypocalcaemic haemodialysis led to rapid increases in PTH. After 15 min, the mean calcium decrement was 0.09 mM (P less than 0.01) and the mean PTH increment was 283 pg/ml (P less than 0.01). The parathyroid response was maximal at 30 min, and did not increase subsequently, despite progressive hypocalcaemia for a further 90 min. During recovery from hypocalcaemia, PTH reduced and, despite comparable hypocalcaemia, PTH during periods of increasing calcium was always lower at a given calcium concentration than while calcium was decreasing. This influence of the direction of change of calcium was not seen during hypocalcaemia. The results showed that even in-advanced renal disease, the parathyroid glands are highly responsive to small initial increments (0.03 mM) and decrements (0.09 mM) in blood calcium, though less so to further perturbation of blood calcium.(ABSTRACT TRUNCATED AT 250 WORDS)

Use of mass spectrometry in the identification of in vivo and in vitro metabolites of dihydrotachysterol3 in the rat

The metabolism of dihydrotachysterol3 (DHT3), a vitamin D analogue, has been investigated in vivo in the rat after intraperitoneal injection, and the metabolism of the 25-hydroxylated metabolite of DHT3 was studied in vitro in the isolated perfused rat kidney. A large number of metabolites have been obtained and some have been identified. The rat plasma or kidney perfusate were extracted and the metabolites separated by high-performance liquid chromatography (HPLC) in straight- and reverse-phase systems and using cyano columns. Metabolites were identified, using a photodiode array assembly which monitored the HPLC eluate, by the characteristic ultraviolet spectrum of DHT compounds. Tentative structures were assigned to some of the metabolites obtained on the basis of their mobility in the various HPLC systems used in comparison to that of known metabolites of vitamin D. Gas chromatography/mass spectrometry (GC/MS) and direct probe mass spectrometry have been used to confirm the identity of seven metabolites formed in vitro, of which only two have been definitely shown also to be formed in vivo. GC/MS was carried out after derivatization forming trimethylsilyl ethers, n-butyl boronate cyclic esters, and N-O-methyl oximes before and after oxidation with sodium periodate and/or reduction with sodium borohydride. Molecular ions of these compounds are usually of low abundance and characteristic mass fragments at m/z 273, 255 and 121 are always seen with metabolites of DHT.

Isolation and identification of seven metabolites of 25-hydroxydihydrotachysterol3 formed in the isolated perfused rat kidney: a model for the study of side-chain metabolism of vitamin D

The in vivo metabolism of dihydrotachysterol3, an analogue of vitamin D3 and a potent calcemic factor, has been studied in the rat. This in vivo metabolism is compared to the in vitro metabolism of 25-hydroxydihydrotachysterol3 in the perfused rat kidney. Using mass spectrometry and ultraviolet spectroscopy, we have identified seven novel metabolites derived from 25-hydroxydihydrotachysterol3. The seven compounds represent intermediates on two renal pathways (24-oxidation and 26,23-lactone formation) also observed for 25-hydroxyvitamin D3. No evidence was found for the renal synthesis of a 1-hydroxylated metabolite of 25-hydroxydihydrotachysterol3 analogous to the hormone 1,25-dihydroxyvitamin D3. Two of the compounds formed in vitro, 24,25-dihydroxydihydrotachysterol3 and 25-hydroxydihydrotachysterol 26,23-lactone, were also formed in vivo. In vivo studies also revealed the formation of two other unidentified metabolites which are presumed to be formed nonrenally and may be calcemic factors. This work shows that dihydrotachysterol3 metabolism is complex and probably utilizes the same side-chain enzymes as vitamin D3. In addition, our work also confirms that intermediates postulated to lie on pathways to 26,23-lactone in the vitamin D3 series are also formed for the side chain in dihydrotachysterol3.

Oral character and attitudes and behavior related to food and eating

Freudian theory predicts that adult personality characteristics and behavior will reflect unresolved conflicts from early developmental stages. In this study, a card from the Blum's Blacky test was used as a projective measure of oral conflict with 35 male and 61 female college students. The presence of such conflict was significantly associated with deviations from norms for body weight, greater variability in adult body weight, rating food as important, and eating more frequently. However, ratings of preoccupation with food were not significantly related to scores for oral conflict. These findings support predictions from psychoanalytic theory and also point to the continued usefulness of the Blacky test in psychoanalytic research.

Aluminium chelation therapy in dialysis patients: evidence for inhibition of haemoglobin synthesis by low levels of aluminium

To investigate the possibility that aluminium may exacerbate anaemia in dialysis patients with only modest aluminium accumulation, 15 patients whose exposure to aluminium had been low were treated for three months with the aluminium chelating agent desferrioxamine, 30 mg/kg intravenously at the end of each dialysis session. Serum aluminium concentrations before treatment were 5-125 micrograms/ml. After one month of desferrioxamine, serum aluminium (including the chelate) had risen from 54.6 (SEM 11.2) to 167.0 (27.5) micrograms/l; and after three months haemoglobin had risen from 8.46 (0.70) to 10.43 (0.80) g/l. Mean cell volume and mean cell haemoglobin concentration also increased significantly. The maximum rise in haemoglobin correlated with the patients' aluminium burden as estimated by the mean serum aluminium concentration after one month of desferrioxamine therapy (r = 0.85). The greatest response to desferrioxamine occurred in patients with a baseline serum aluminium of 15-75 micrograms/l (mean increase in haemoglobin 38%). The results indicate that even the modest aluminium accumulation found in most dialysis patients has a pronounced inhibitory effect on haemoglobin synthesis. The possible toxic effect of aluminium should be considered in all anaemic dialysis patients.

Biliopleural fistula as a complication of percutaneous biliary drainage: experimental evidence for pleural inflammation

We describe 3 patients in whom biliopleural fistulae complicated percutaneous biliary drainage. All patients had complete obstruction of their biliary tree because of malignancy. Biliopleural fistulae developed as a complication of inadvertent catheter removal in 2 patients and of catheter dysfunction in the third. Early reinstitution of biliary drainage and successful drainage of the pleural space led to complete recovery in all patients. An animal model to evaluate the effects of bile in the pleural space in normal rabbits revealed rapid absorption of bilirubin, the production of a polymorphonuclear-predominant exudative effusion with extremely high LDH levels, and resolution with a macrophage influx. We conclude that biliopleural fistulae are heterogeneous in their presentation, depending upon the persistence of biliary drainage into the pleural space, the volume of exudative effusion, and the presence of suppurative complications.

Simulated acidosis does not impair 1,25-dihydroxyvitamin D3 production by cultured kidney cells

Cultured mouse kidney cells grown in serum-free medium were used to assess the metabolism of 25-hydroxyvitamin D3 in the presence of simulated metabolic acidosis. Kidney epithelial cells isolated from 4-6 week old mice were grown to confluence in a defined serum-free medium at pH 7.4. The confluent monolayers were incubated with tritiated 25-hydroxyvitamin D3 for 6 hours, the samples were extracted, and vitamin D metabolites were separated and quantitated by high pressure liquid chromatography (HPLC). The pH of the incubation medium was set at 6.9, 7.1, 7.4, or 7.7 by adjusting the bicarbonate concentration, using chloride as the balancing anion at constant Pco2. When pH was altered at the beginning of the 6 hour assay, production of 1,25-dihydroxyvitamin D3 was the same at each pH. More prolonged pH perturbation for a total of 30 hours likewise had no influence on 1,25-dihydroxyvitamin D3 production. These results confirm that intact mammalian kidney cells in serum-free culture possess an active 25-hydroxyvitamin D3-1-hydroxylase and that the activity of the enzyme is unaffected by pH over the range 6.8-7.7. In experiments where acidosis has been shown to alter 1,25-dihydroxyvitamin D3 production, the mechanism was probably indirect.

Residual renal function in hemodialysis patients may protect against hyperaluminemia

We investigated 106 home hemodialysis patients whose mean [+/- SEM] serum aluminum (Al) concentration was 60.9 +/- 4.1 micrograms/liter. Serum Al concentration was inversely related to daily urine output (r = -0.52, P less than 0.001). Urine volume and measurements of Al exposure were included in a multivariate analysis of serum Al concentration in the 62 patients whose urine output was greater than 10 ml/day. The multiple correlation coefficient (r) was 0.70 (P less than 0.001) and the percentage contributions to r2 (indicating the relative importance of each factor) were: urine output 57%, oral Al intake 36%, total dialysis hours 7%. The additional contribution from cumulative water Al was negligible. In a subgroup of 26 patients with a urine output exceeding 10 ml/day, urinary Al excretion averaged 15.4 micrograms/day, and renal Al clearance and serum Al concentration were inversely related (r = -0.69, P less than 0.001). We conclude that Al-containing phosphate binders were a more important source of Al than was dialysate in these patients and that residual renal function can reduce the severity of hyperaluminemia in hemodialysis patients.