Significance of tissue polypeptide antigen (TPA) levels in nasopharyngeal cancer

Serum levels of tissue polypeptide antigen (TPA) were measured in 233 patients at the time of initial diagnosis of nasopharyngeal carcinoma (NPC). Staging of NPC was done using Ho's recommendations together with computerised tomography (CT) of skull findings. The upper limit of normal serum TPA levels in our population was noted to be 112 U/1. In 126 patients with N0 and N1 lymph node staging, the mean level of TPA was 90 U/1 +/- 9 (standard error of mean, sem), while in 107 patients with N2 and N3 nodal disease the mean was 193 U/1 +/- 25.6 (p less than 0.001). Similarly, in 162 patients with T1 and T2 disease, the average TPA level was 119 +/- 13.4 while in 71 patients with T3 disease, the mean TPA was 179 U/1 +/- 29.8 (p less than 0.03). Of 200 patients without metastases, the mean TPA level was 112 +/- 12 U/l whereas in 33 patients with known metastases in liver, lung, bone or brain, the mean TPA level was 290 +/- 51 (p less than 0.001) with liver metastases producing the highest levels. The present study indicates rising values of TPA with advancing nodal and tumour stage in NPC, with high values in metastatic disease. There is a highly significant correlation between nodal stage and TPA levels. TPA is a useful marker in the staging and follow-up of NPC patients.

99mTechnetium(V) dimercaptosuccinic acid (99mTc(v) DMSA) as a tumour seeking agent in nasopharyngeal carcinoma

We prepared 99mTechnetium(V) DMSA (pentavalent form) as an imaging agent for eighteen patients with proven nasopharyngeal carcinoma. The head, neck, chest and abdomen were scanned. The nasopharyngeal tumour showed tracer accumulation in only 5 out of the 18 patients (28%). The study indicates that 99mTechnetium(V) DMSA is not a useful radiopharmaceutical for visualising nasopharyngeal tumours although it may have other useful properties.

Estradiol binding capacity of breast cancer cell line in correlation with cell cycle

The specific estrogen binding capacity of the MCF-7 cells has been studied throughout the cell cycle. Two days after plating 1-4 X 10(5) cells per well, we observed that cell number, protein concentration and DNA level began to rise but the estrogen binding capacity was lowered. At logarithmic phase the binding increased gradually then sharply to just before confluency. When the cells reached the quiescent phase the estrogen binding capacity fell rapidly. Since estrogen binding capacity of the intact MCF-7 cells varies with different phases in the cell cycle as well as the incubation temperature and time and the plating density, all these factors should be taken into consideration when this cell line is used for hormone studies.

Autoimmune disease--pathogenesis through molecular mimicry at the tripeptide level

Increasingly it is being discovered that short segments of proteins can provoke an immune response. Sequential determinants are as important as conformational determinants. It is the thesis of this paper that a string of three amino acid residues (a tripeptide) is antigenic when it is located on a large carrier, that is, when it is part of a protein. Conceptually this has great explanatory power in understanding (a) autoimmune phenomena (b) the intriguing finding that monoclonal antibodies which are supposed to be exquisitely specific cross-react with disparate, non-homologous proteins. Clinical syndromes such as the neuropathies of myeloma, hepatitis and multiple sclerosis are discussed in the light of this concept by computer analysis of the putative antigenic sites of myelin basic protein, hepatitis B and A proteins and measles peptides.

Tissue polypeptide antigen (TPA) and beta 2-microglobulin (beta 2-MG) as tumour markers in nasopharyngeal cancer

The levels of tissue polypeptide antigen (TPA) and beta 2 microglobulin (beta 2-MG) were measured in the serum of 38 patients with nasopharyngeal carcinoma (NPC). Using sera from 35 normal volunteers and blood donors, a normal range for these two tumour markers was established. The normal range for TPA was 40-148 IU/L (mean = 93), while that for beta 2-microglobulin was 0.9-2.0 mg/L (mean = 1.3). In the patients with NPC but without known metastases the range was 63-178 IU/L for TPA (mean = 111) and for beta 2-MG, the range was 1.0-3.1 mg/L (mean = 1.7). For those NPC patients with metastases to bone or liver, the mean TPA was 464 IU/L and the mean beta 2-MG was 4.3 mg/L. It appears that TPA and beta 2-MG are useful markers for the monitoring of NPC patients for metastatic disease, particularly TPA.

Quality control of estrogen and progesterone receptor assays

The intra-laboratory QC materials for estrogen and progesterone receptor assays were prepared using different methods. The most convenient and economical method was found to be the use of lyophilized rat uterine cytosol. The level of receptors remained stable for 12 months when stored at -70 degrees C with the inclusion of 10 mM phenylmethyl sulfonyl-fluoride in the cytosol extraction buffer. For inter-laboratory comparison, we received QC materials from Dr E D Ryan (McMaster University, Canada) monthly and our results fell within +/- 1SD of the mean value of 15 centres from North America and Europe participating in this program.

Serum thyroglobulin (Tg) and thyroglobulin antibodies (TgAb) in thyroid cancer

Serum thyroglobulin antibodies (TgAb) and serum thyroglobulin (Tg) levels were measured in 28 normal controls and 32 patients with differentiated thyroid cancer. The TgAb and Tg levels were measured in the patients when they were on replacement thyroxine therapy prior to the whole body radioiodine I-131 scan (WBS), using immunoradiometric assay kits. The TgAb level in normal controls was from 0-4.8 micrograms/ml, with a mean of 0.6 microgram/ml, while the Tg level in these controls was from 0.0-48.0 ng/ml, with a mean of 4.2 ng/ml. In the patients with thyroid cancer, the TgAb levels were normal except for a few patients who had residual thyroid or tumour in the neck and had raised levels of TgAb. Their Tg levels were normal except for 7 patients who had elevated values. 2 of these 7 had no evidence of disease on X-ray, bone scan, or WBS (I-131) while the other 5 had evidence of metastases. However, 4 patients had metastatic disease with normal Tg levels, and 2 of these patients had residual thyroid in the neck and raised TgAb levels, while in the remaining 2 patients, both Tg and TgAb were low. Serum Tg is a useful tumour marker for recurrent or metastatic thyroid cancer, but the presence of residual normal thyroid would interfere with the results.

Postmortem endocrine levels in the vitreous humor

The vitreous humor and sera from 51 autopsy cases were assayed for progesterone, estradiol, thyroxine, triiodothyronine, TSH, FSH, LH and prolactin. The results indicate that the blood retinal barrier has unique properties of its own. All hormones were measurable in the sera. Progesterone, estradiol, T3 and T4 were not detected despite their lipid solubility and their small molecular size while the larger glycoprotein hormones were easily measureable.

Glucose tolerance test and insulin levels in children with transfusion-dependent thalassaemia

Blood glucose and serum immunoreactive insulin levels were measured following an oral glucose load in 20 unrelated children with multiple transfused thalassaemia. Results suggest that even though overt diabetes and glucose intolerance are uncommon before the age of 13 years, the presence of insulin resistance is evident, especially in those who have been splenectomized.

Correlation of steroid receptors with histologic differentiation in mammary carcinoma. A Singapore experience

Cancer of the breast is the most common tumor in females in Singapore, with the rate of 20.7 per 100,000 per year (1977 estimate), which is predicted to increase to 29.8 per 100,000 women per year by 1995. A detailed histopathologic review of 50 primary breast cancer tumors analyzed for estrogen receptor (ER) level was carried out and a variety of morphologic features correlated with ER results to identify any factors that will improve the management and prognosis for breast cancer. Cytosol was incubated with 3H-estradiol in the presence and absence of cold diethylstilbestrol, and bound and free hormone were separated by Dextran-coated charcoal method. Tumors binding more than 5 fmol/mg cytosol protein were classified as ER-positive. Progesterone receptor (PR) level was analyzed in some specimens with the use of a similar method. Most of the patients were Chinese (90%). Three patients were Malays, one was Indian, and one was European in this series. Results indicated that there was strong correlation between ER level, age, and histologic grade of the tumors. No correlation existed between absence or presence of lymph node metastases and ER. Although there was a trend for ER-positive tumors to have a low-grade lymphocytic infiltration, the difference was not statistically significant.

The incidence of atopy in steroid-responsive nephrotic syndrome: clinical and immunological parameters

Fifty-nine children with steroid-responsive nephrotic syndrome (SRNS), ages ranging from two to 18 years, were studied to determine the incidence of atopy, using both clinical and immunological parameters. Children with SRNS were found to have a significantly higher incidence of atopy both in themselves (z = 2.51, p less than 0.05) and their first-degree relatives (z = 2.34, p less than 0.05). The proportion of children with raised serum IgE levels (60%) and the geometric mean (631 U/ml) in SRNS children were significantly higher than control values, 14.5% and 136 U/ml, respectively (p less than 0.0001). Intra-group comparison showed that children with multiple relapses (more than two relapses) had higher incidence of skin test positivity to house dust mite (p less than 0.01) and to two or more antigens (p less than 0.05). Our data would suggest that atopy may be a predisposing factor in local children with SRNS.

Nuclear medicine--an overview

A radioactive isotope behaves chemically and biologically like its non-radioactive counterpart. The application of this principle to medical diagnosis has evolved into a whole specialty called nuclear medicine. The development of the rectilinear scanner and gamma camera has extended the study of molecular pathways into an exciting imaging modality while developments in radiopharmaceuticals have made radionuclide imaging of many organ systems widely available. The most significant improvements have occurred in bone, hepatobiliary and cardiac imaging. Today, however, nuclear medicine is evolving into a more dynamic study of physiological processes in the body and how these processes may be affected by disease and medical treatment. Emission tomography with a new generation of both gamma and positron emitters will be integral part of nuclear medicine in the future. The challenge to develop radio-labelled antibodies for immunotherapy and immunodetection remains while many of the older techniques like radioimmunoassay, and even the simple colloid liver scan, will continue to contribute significantly to health care.

The molecular biology of cancer and its diagnostic implications

The origin of cancer is discussed from the view of the two-stage model of malignant transformation. Environmental carcinogens play an integral part in the process. When the cell is transformed, cell surface changes are found for such components as fibronectin, collagen, actin, myosin, glycopeptides and enzyme activities. Hormone receptors are a fruitful line for research. Both qualitative and quantitative alterations are also seen with cancer cell enzymes. Among enzymes that can be used as markers of malignancy are the protease. A group of oncodevelopmental proteins, hormonal and non-hormonal, are in regular service for the management of cancer. Improvements in diagnostic specificity can be expected as the newer technologies are harnessed for medical use.

The radioimmunoassay of human serum albumin with antibody adsorbed on porous glass beads

A convenient method for the radioimmunoassay of human serum albumin (HSA) is presented. It utilises porous glass beads on which rabbit anti-HSA has been strongly adsorbed. Assay time is less than an hour: no centrifugation is required and the range is 50--1,000 ng ml-1.

The radiometric assay of microsomal UDP-glucuronyltransferase using 125I-labelled phenolphthalein

A rapid and sensitive method is described for assaying UDP-glucuronyl-transferase (EC 2.4.1.17) activity. The substrate is the relatively apolar phenolphthalein, labelled with 125I on one of its two phenolic rings leaving a free hydroxyl group for glucuronidation. Extraction with ethyl acetate leaves the glucuronide in the aqueous reaction medium which is then counted. Less than 10 mug microsomal protein is required and the glucuronidation of 10 ng 125I-labelled phenolphthalein (0.03 nmoles) is easily detected.

The radiometric assay of alkaline phosphatase activity with 125-I-labelled phenolphthalein monophosphate

The coupling of 125-I to phenolphthalein monophosphate is described. Hydrolytic cleavage of the phosphate group by alkaline phosphatases (EC 3.1.-3.1) releases labelled phenolphthalein which is extracted into ethyl acetate at pH 10. This forms the basis of a sensitive assay for the enzyme with the advantages of sensitivity and rapidity from the use of a gamma-emitter. Results with Escherichia coli and calf intestine alkaline phosphatases are presented.