Improved performance of plasma gonadotrophin assays using common reagents and assay protocols: evidence from the UK External Quality Assessment Scheme

Radioimmunoassay kits prepared in the Chelsea Hospital for Women for follicle stimulating hormone (FSH) and luteinising hormone (LH) have been used in 26 UK laboratories for over 2 years. Data from the UK External Quality Assessment Schemes for FSH and LH have been used to provide an independent assessment of the performance of these kits over a 12-month period. For both analytes, users of the kits were found to have: a low variability of the bias, implying good within-laboratory, between-assay precision; a lower between-laboratory, within-sample geometric coefficient of variation than users of 'own' methods, implying better between-laboratory agreement; method bias that did not differ significantly from laboratories using 'own' method protocols. This survey indicates that a non-commercial organisation can produce immunoassay kits that improve the quality of FSH and LH assays generally available.

Urinoma complicating papillary necrosis in diabetes

Images

The acquisition of immunity to Histophilus ovis by sheep in nature

It was demonstrated that skin wound infection with Histophilus ovis elicits an immune response which can protect a ram against a challenge injection of the same organism into its epididymis.

Immunity against genital infection by Histophilus ovis in rams

Rams have been immunized against an infection of their genitalia by Histophilus ovis. An alum-precipitated antigen and an antigen plus Freund's complete adjuvant proved equally effective. An injection of live H. ovis into the epididymal tissue proved to be a better method of challenging immunity than an injection into the vas deferens. It was shown that cell-mediated immunity, as evidenced by tests for lymphocyte transformation, the presence of a macrophage migration inhibition factor and a delayed hypersensitivity skin reaction did not play a role in the resistance, nor did specific IgG antibodies have any protective influence. It was shown that neutrophils play a cardinal role in the immunity against H. ovis infection in so far as they phagocytize and destroy the organisms and are attracted to them by chemotaxis in immune animals.

Unusual response of lymphocytic lymphoma (not hairy cell leukaemia) to splenectomy without chemotherapy

An unusual period of prolonged disease control after splenectomy without chemotherapy was achieved in 3 cases of B-cell lymphocytic lymphoma with pancytopenia, massive splenomegaly, minimal lymphadenopathy and circulating hairy cells. The finding of distinctive histopathological features in the bone marrow, lymph nodes and splenic tissue enabled this unusual condition to be characterized and differentiated from hairy cell leukaemia, which may have similar presenting features and in which response to splenectomy is generally good.

Acetaldehyde binds to liver cell membranes without affecting membrane function

Acetaldehyde is a major metabolic product of ethanol and is found in high concentrations in the serum during alcohol abuse. The effects of acetaldehyde on isolated rat liver cells and on purified hepatocyte plasma membrane vesicles have been studied. In concentrations of 0-10 millimolar acetaldehyde has been shown to have no detectable effect on either hepatocyte metabolism or gross membrane function and is therefore unlikely to act as a direct metabolic poison. Acetaldehyde, however, is shown to bind to hepatocyte membranes via intermediary Schiff's base formation. The adduction of acetaldehyde to liver cell plasma membranes may have an effect on membrane structure. These findings are consistent with the hypothesis that any injurious effect of acetaldehyde on the liver may be mediated via the immune system rather than being a direct effect on cell metabolism.

Mortality experience of glass fibre workers

A historical prospective mortality study was conducted at an insulating wool plant in Ontario, Canada, on 2576 men who had worked for at least 90 days and were employed between 1955 and 1977. Eighty eight deaths were found in the 97.2% of men traced. Mortality was compared by the person-years method with that of the Ontario population. Measurements taken since 1977 show very low fibre concentrations. The overall standardised mortality ratio (SMR) was 78%, significantly below 100. Among plant only employees, seven deaths were attributed to lung cancer compared with 4.22 expected, a non-significant excess (SMR = 166; 95% confidence limits 67 to 342). No confirmed cases of mesothelioma were observed and no other disease was significantly increased in plant workers.

An investigation of the attitudes of medical students to physically disabled people

A study was carried out to investigate the change in attitudes towards physically disabled people of a group of fifty-eight medical students during the first 3 years of their course. The students attended a newly established medical school which has developed a curriculum without the traditional division into preclinical and clinical years and where contact with patients occurs from the first year. Results demonstrated that, as expected, at the start of the course the attitudes of females towards disabled people were more positive than those of males. Also, a significant change in attitudes was found after 3 years, both males and females demonstrating more positive attitudes toward physical disability. The differences between males and females were maintained. The relationship between these students' attitudes and their behaviour was discussed and proposals for further research to investigate this are outlined.

Retardation of wool growth in Merino sheep caused by bacteria

A condition evidenced by retarded growth of wool with alteration of the yolk into a yellow, sticky, wax-like substance was investigated. The condition was associated with hyperaemia and cellular infiltration into the dermis in the affected areas. Three bacterial species, viz. Enterobacter aerogenes, E. agglomerans and Hafnia alvei, which could grow on the water-extractable component of wool-yolk, were incriminated as the cause of the condition.

Diagnostic value of trephine biopsy in bone disease

A clinical diagnosis of myeloma was made in a 44-year-old woman with anaemia, a markedly raised erythrocyte sedimentation rate, osteolytic lesions in the pelvis, and a pathological fracture of the femur. Confirmatory trephine biopsy showed, instead of plasma cell infiltration, destruction of the normal micro-anatomy of the marrow with bridging fibrosis, gross osteoclastic proliferation, and areas of new bone formation. These are the features of hyperparathyroidism. Subsequently, a solitary adenoma of the parathyroid glands was demonstrated and resected. This case illustrates the value of examination of the trabeculae in trephine biopsy specimens in the diagnosis of bone disease.

The reaction of ovine neutrophils to Histophilus ovis in relation to genital infection of rams

Histophilus ovis was shown to be phagocytized by neutrophils when the organisms enter the lumen of the reproductive tract of the ram. The phagocytosis and destruction of H. ovis by neutrophils was demonstrated in vitro by the viable count method and by electron microscopy. It was shown that immunoglobulins and complement had no influence on the phagocytosis and destruction of H. ovis. Phagocytosis and killing of H. ovis was accomplished equally well by neutrophils from immunized and non-immunized rams. Immunized rams showed a massive infiltration of neutrophils into the walls, epithelium and lumen of their ampullae when dead H. ovis were introduced into their lumen.

Use of multivariate analysis to improve the accuracy of radionuclide angiography with stress in detecting coronary artery disease in men

A multivariate analysis (MVA) system was derived retrospectively from a population of 76 males with coronary artery disease and 18 control subjects. Posterior probabilities were then derived from such a system prospectively in a new male population of 11 subjects with normal coronary arteries and hemodynamics and 63 patients with coronary artery disease. The sensitivity was 84% compared to that for change in ejection fraction (delta EF) greater than or equal to 5 criterion of 71% (p less than 0.01), the specificity was 91% compared to 73% for the delta EF greater than or equal to 5 criterion (p greater than 0.05), and the correct classification rate was 85% compared to 72% for the delta EF greater than or equal to 5 criterion (p less than 0.01). The significant variables were: change in EF with exercise, percent maximal heart rate, change in end-diastolic volume (delta EDV) with exercise, change in R wave, and exercise duration. Application of the multivariate approach to radionuclide imaging with stress, including both exercise and nuclear parameters, significantly improved the diagnostic accuracy of the test and allowed for a probability statement concerning the likelihood of disease.

Plasma prednisolone studies in rheumatic patients

Prednisolone concentration in plasma after a daily maintenance steroid dose was monitored in 83 patients with rheumatic diseases. Although no restrictions were imposed on the intake of food or drink, plasma drug levels tended to peak at 1 h after the ingestion of the standard tablets, whereas intestinal absorption of the enteric-coated preparation was found to be most unpredictable. A profound individual variation was observed in plasma prednisolone concentrations, and neither total nor unbound drug levels showed any consistent relationship with the size of the prednisolone dose or the control of the disease activity. The basal cortisol production was suppressed in one-third of the patients. There is no support from this study for the concept of an 'optimum therapeutic range' of plasma prednisolone for the treatment of rheumatic disease.

Student characteristics on entry to an innovative medical programme

The interests, attitudes and motivations of two groups of first-year medical undergraduates, one group from an innovative medical school and one group from a more traditional school were compared. Differences were found between the two groups in their reasons for studying medicine, their attitudes to medical education, and the role of the medical profession. The students from the innovative school placed more emphasis on the interpersonal and practical aspects of medicine as well as a sense of responsibility to the community. Reasons for these differences were discussed.

A standardised multicentre procedure for plasma gonadotrophin radioimmunoassay

A radioimmunoassay method for the assay of luteinising hormone (LH) and follicle-stimulating hormone (FSH) in serum/plasma has been designed for use in laboratories of varying expertise in the United Kingdom. The major sources of experimental error leading to poor within-laboratory performance and between-laboratory comparability were identified: quality of tracer, use of calibration standards, and separation procedure. A simple rugged kit was designed which was extensively tested first in our laboratory and then in a small multi-centre field trial before being made available. It is now used routinely by 26 health service and research laboratories. The working range of the assays is 1-50 IU/l (LH) and 0.3-16 IU/l (FSH). The between-batch reproducibility was 5-11% (CV) over the dose range 4.8-18 IU/l (LH) and 1.6-15 IU/l (FSH).

Inverse relationship between onset and duration of EEG effects of six peripherally administered peptides

Electrical activity in the rat brain after the peripheral injection of equimolar (0.1 mM) doses of Metenkephalin, Leu-enkephalin, beta-endorphin, gamma-endorphin, DSIP, and alpha-MSH was assessed by power spectral analysis. The mean onset of EEG activity for each peptide varied between 13.7 and 20.7 minutes and lasted between 27.8 and 40.8 minutes. The significant (p less than 0.001) interaction between duration and latency revealed that the longer the latency, the shorter the duration. Similar findings were observed after injection of the same peptides at a fixed dose of 80 microgram/kg body weight. Thus, the results demonstrate that peripherally injected peptides can exert EEG effects that last longer the sooner they start.

Radionuclide angiographic correlation of the R wave, ejection fraction, and volume responses to upright bicycle exercise

The change in the R wave and the response of the ejection fraction to upright bicycle stress testing with radionuclide angiographic studies were determined for 18 control subjects and 29 patients with coronary arterial disease (70 percent stenosis or more). In the control group, all had an increase in the ejection fraction from 64.8 +/- 7.7 to 75.7 +/- 9.4 percent with stress (P less than 0.01). All control subjects had a decrease in the R wave with exercise. In the group with coronary arterial disease, most patients had a decrease in the ejection fraction averaging from 63.5 +/- 10.9 to 58.6 +/- 12.8 percent (P less than 0.01). An appropriate response of the R wave and ejection fraction (decrease in R wave and increase in ejection fraction or increase in R wave and decrease in ejection fraction) occurred in 23 (79 percent) of 29 subjects (P less than 0.005). The sensitivity, specificity, and predictive value for the response of the ejection fraction were as follows: 83 percent (24/29); 100 percent (18/18); and 100 percent (24/24). Of the patients with coronary arterial disease and an increase in the R wave, 17 (94 percent) had multivessel disease, while six (55 percent) of 11 with a decrease in the R wave had multivessel disease (P less than 0.05). The systolic volume decreased in all control subjects by -15.9 +/- 8.6 units (P less than 0.01) and increased in most of the group with coronary arterial disease by 13.7 +/- 17.8 units (P less than 0.01) in response to stress. There were 20 of 29 patients (P less than 0.05) with an appropriate response of the R wave and systolic volume to stress (increase in R wave and systolic volume or decrease in both). The change in the R wave did not correlate with the change in the diastolic volume with stress (P greater than 0.05). Changes in the R wave with exercise correlate with the change in the ejection fraction (and hence ventricular function) and with the changes in systolic volume, which may be one of the mechanisms of the response of the R wave, suggesting that the change in the R wave is related to changes in contractility. Increase in the R wave with stress suggests multivessel coronary arterial disease.

Stress reactions involving the pars interarticularis in young athletes

A stress reaction involving the pars interarticularis of the lumbar spine was confirmed in seven young athletes with a positive technetium pyrophosphate bone scan. No pars defects were detectable on their lumbosacral roentgenograms, which included oblique views. The return to normal levels of radioactive uptake on repeat bone scans correlated closely with their clinical course. If the bony reaction is recognized early, it may heal at a subroentgenographic level and prevent the development of lumbar spondylolysis. These early lesions usually show unilateral increased uptake at one lumbar level on the bone scan and, initially, the athlete localizes the pain to the corresponding unilateral lumbar paraspinous area. The "one-legged hyperextension test" is positive on the ipsilateral side and aggravates the pain. Treatment consists of avoiding the aggravating activities and resting. The average time for return to pain-free competition was 7.3 months. These developing defects may be the source of considerable prolonged disability in the young athlete, particularly if undiagnosed and untreated.

Effect of synthetic thyrotrophin-releasing hormone and its analogues on growth hormone secretion in the domestic fowl (Gallus domesticus)

Variations in plasma growth hormone (GH) concentrations following iv or sc administration of synthetic thyrotrophin-releasing hormone (TRH, Pyr-His-Pro-NH2) have been followed in immature and adult domestic fowl. TRH markedly stimulated GH secretion in newly hatched (1 and 2 day old) chicks and in 6-week-old cockerels but in adult male or female birds of two strains had very little effect, if any. Intravenous injection of 4 TRH analogues (Pyr-His-Mep-NH2, Pyr-Meh-Mep-NH2, Pyr-Meh-Mep-NH and Pyr-Meh-Pro-NH2) were also potent GH secretagogues in 6-week-old birds. The stimulatory effect of TRH or the TRH-analogues on GH secretion was not dose-related.

Prednisolone concentrations in plasma, saliva and urine

Prednisolone was measured in plasma, saliva and urine at various times after a single dose. Peak plasma prednisolone levels were observed about 1 h after the dose. Saliva prednisolone levels were measurable for at least 3 h after dosing but showed no consistent relationship to either total or free plasma prednisolone concentrations. Unchanged prednisolone in amounts up to 14% of the dose administered was found in the 24 h urine and most of it was excreted in the first 5 h.

Lung imaging with radioaerosols for the assessment of airway disease

Aerosol inhalation lung scans offer distinct advantages in the evaluation of airways and the qualitative distribution of ventilation. The sensitivity in detecting mild obstructive disease is similar to that of xenon washout and both probably surpass standard pulmonary function tests that measure total rather than regional ventilation. Although imaging studies using krypton gas are ideal for assessment of rapidly ventilated space, krypton's short half-life precludes its usefulness for demonstrating air trapping. Neither 133Xe nor 81mKr gas demonstrates sites of airway abnormality as aerosol does. Aerosols are ideal for the general nuclear medicine practice in community hospitals because of their convenience, cost effectiveness, and information yield. Current technique using same-day multiple-view aerosol scans after a preliminary perfusion scan, makes use of the most logical diagnostic scheme in the vast majority of patients with chest complaints, since a normal perfusion scan often eliminates the need for a ventilation scan.

Improved radioaerosol administration system for routine inhalation lung imaging

An improved radioaerosol administration system has been developed to reduce the number of droplets larger than 2.0 micron in diameter which have caused abnormal hyperdeposition of inhaled aerosols in the large airways. The new system has achieved this goal by interposing a reservoir-setting bag in the aerosol delivery line between the nebulizer and the patient. The components are inexpensive, commercially available and easily assembled in any nuclear medicine service.

Surfactant Aging: A Possible Detriment to Tertiary Oil Recovery

Introduction

New processes for achieving improved oil recovery have been under development in the petroleum industry for many years. One such process, termed surfactant flooding uses surfactants to minimize oil/water capillary forces. The petroleum sulfonates are of interest as surfactants by virtue of their low cost. However, there are problems. Foster has shown that the low interfacial tensions required for efficient displacement are sensitive functions of surfactant concentration and salinity.

Aqueous solutions of petroleum sulfonates appear to change with time. This tension aging has been found to occur in both the presence and absence of certain cosurfactants. Also visually striking are the metamorphic changes that slowly occur when the surfactant is carefully contacted with an aromatic hydrocarbon without mixing the two phases. The aging processes described here evolve through nonequilibrium states, some of which may be detrimental to oil-recovery processes. These nonequilibrium aging states develop slowly (over a period of months, perhaps even years) and would not influence model displacements lasting only a few days or weeks; but they would be significant in the time frame over which a tertiary oil-recovery program is conducted.

Experimental Procedure

All the pure hydrocarbon oils studied were spectroscopic grade. Further purification had no effect on their interfacial tensions and, therefore, they were used as received from the manufacturer, Chem Samples. The hydrocarbon mixture designated as pseudocrude is described elsewhere. Witco Chemical Co. supplied the petroleum sulfonate designated as TRS 10-80, and Shell Development Co. provided the Martinez 380 and Martinez 470.

The aqueous surfactant/salt solutions were prepared using the surfactant as received, always adding the sodium chloride last.

All the interfacial tension measurements were made without pre-equilibrating the two phases. The values of the tensions for these systems were obtained at 25 deg. C using a spinning-drop interfacial tensiometer.

Results and Discussions

Low Tensions and Surfactant Aging

A substantial difference in some interfacial tensions was discovered when two surfactant solutions of differing ages were used to measure the interfacial tensions of three homologous hydrocarbon series. These three hydrocarbon series were (1) n-alkanes from pentane to heptadecane, (2) n-alkylbenzenes or 1-phenylalkanes from benzene to heptadecylbenzene, and (3) n-alkylcyclohexanes or 1-cyclohexylalkanes from cyclohexane to n-tridecylcyclohexane. Both aqueous phases conMined 0.2-percent surfactant/1.0-percent salt and were prepared using the same technique. prepared using the same technique. JPT

P. 985