Pneumatic otoscopy in the diagnosis of middle ear effusion: the use of video as a teaching aid

A recent survey has shown that the average general practitioner could expect to see 40 episodes of middle ear effusion in one year. It is an important condition because of its frequency, its insidious onset, and its persistence. It is presently associated with hearing loss, resulting in educational and social disadvantages. A more accurate diagnosis can be made over other conventional methods by the use of pneumatic otoscopy. It is a technique that is not widely used by general practitioners in this country. A videotape was produced to demonstrate the behaviour of the normal and abnormal eardrum during pneumatic otoscopy. This paper gives a review of how this was achieved.

Expression of the oncogenes mil and ras abolishes the in vivo differentiation of mammary epithelial cells

Three carcinoma-associated oncogenes, two of which have been strongly implicated in human mammary tumorigenesis, have been introduced into a novel mouse mammary epithelial cell line, EF43, that retains many differentiated functions. The effect of oncogene expression upon classical transformation parameters as well as parameters specific for mammary epithelial cells such as growth in three-dimensional collagen matrices and the ability to repopulate the cleared mammary fat pad and to form alveolar structures in vivo has been investigated. Expression of v-myc in EF43 cells results in no obvious phenotypic changes, and does not confer tumorigenic potential upon the cells. Expression of v-Ha-ras confers upon EF43 cells the ability to grow rapidly, grow in an anchorage-independent manner, results in tumor formation in nude and syngeneic animals, abolishes their ability to repopulate the mammary gland and, instead, results in rapid induction of anaplastic tumors. The v-mil oncogene, an avian homolog of the mouse v-mht and human c-raf oncogenes, previously thought to be non-transforming in the absence of a co-operating oncogene, transforms EF43 cells, allowing them to grow in an anchorage-independent manner, form tumors in nude mice and abolishes their ability to repopulate the cleared mammary fat pad. In contrast to v-ras, however, the tumors arising from v-mil expression have a differentiated morphology, typical of adenocarcinomas. Thus, different oncogenes show varying degrees of inhibition of the differentiation of mammary epithelial cells in vivo.

Quinidine-induced allergic granulomatous angiitis: an unusual cause of acute renal failure

A case of systemic allergic-type vasculitis after the administration of quinidine and digoxin is described. The renal biopsy findings are unique in that they describe an arteritis with eosinophilic infiltration and non-caseating granulomata. We believe quinidine is the antigen that was responsible for the reported findings.

Parathyroid hormone directly inhibits tubular reabsorption of bicarbonate in normocalcaemic rats with chronic hyperparathyroidism

The hypothesis that chronic metabolic acidosis encountered in some patients with primary hyperparathyroidism is due to inhibition of proximal HCO3 reabsorption has recently been challenged. Indeed, this action of parathyroid hormone (PTH) has only been observed in acute studies, whereas in animal models of chronic hyperparathyroidism a metabolic alkalosis has been induced, probably owing to the release of alkaline salts from bone tissue, and to the stimulation of tubular acid secretion by hypercalcaemia. Studies were, therefore, performed to determine the effect of PTH on the renal handling of HCO3 in an animal model in which changes in plasma calcium and phosphate, and nephrocalcinosis, all known to affect tubular acidification, did not occur. Thyroparathyroidectomized (TPTX) rats were infused with synthetic bovine hormone fragment bPTH 1-34 via Alzet minipumps at the rate of 0.7 U h-1 to simulate normal endogenous production of PTH (group I) and at the three-fold higher rate of 2.1 U h-1 (group II). In order to prevent changes in serum calcium and phosphate, and nephrocalcinosis, animals of group II were fed a Ca- and P-free diet prior to TPTX (compared with a regular diet for group I) and both groups were treated with dichloromethylene-diphosphonate (Cl2MDP, 10 mg kg-1 day-1) and a Ca-free diet during PTH infusion. During the course of PTH infusion both groups of animals had stable and normal levels of plasma calcium and phosphate.(ABSTRACT TRUNCATED AT 250 WORDS)

In vitro replication potential of serially passaged mammary parenchyma from mice with different reproductive histories

Growth properties of multicellular units (organoids) of mouse mammary parenchyma have been analyzed. These intact units grew differently in collagen-matrix cultures than did dispersed cells prepared from them. The latter actively migrated in the collagen matrix and reorganized themselves into multicellular structures before producing three-dimensional protuberances in gel. Terminal unit (end-bud/alveoli)-enriched fractions grew more extensively than did ducts, as predicted from growth patterns in vivo. To assess the growth potential and the relationships between replication history in vivo and replication potential in vitro in mammary parenchyma, intact terminal units from mammary glands of mice of different ages and with different reproductive histories were isolated and their growth characteristics compared. Terminal-unit organoids were cultured in collagen gel matrix and passaged weekly for up to 5 weeks. Morphology, growth rates, and growth fractions were compared among organoids from young virgin, old virgin, monoparous, and multiparous mice. Morphologies observed in various passages of organoids from the groups of mice were similar. Organoids from old virgin and multiparous mice declined in growth rate for four passages and then growth rate increased again during the fifth passage. (However, fifth-passage organoids failed to form tumors if implanted in syngeneic mice in vivo.) Growth of organoids from either old or young virgin mice was less at any given passage than tissue from multiparous mice of similar age. Growth fractions of organoids from old parous mice were the same as those from old virgin mice but reached the same maximum fraction faster. Later passage organoids from the different mouse groups responded morphologically to the hormone combination of estrogen, progesterone, prolactin, and cortisone but not respond to cholera toxin. These results suggest that an animal's hormonal history (altered profoundly by pregnancy and lactation) may be as important as chronological age in determining subsequent growth potentials of mammary epithelium.

Animal model of primary hyperparathyroidism

An experimental model of hyperparathyroidism was developed in the rat to simulate primary hyperparathyroidism in humans. In this model thyroparathyroidectomized (TPTX) or parathyroidectomized (PTX) animals were infused for 6 days with an amount of bovine synthetic parathyroid hormone (PTH)-(1-34) fragment to restore plasma calcium levels to normal (0.7 U X h-1) or with PTH at twofold (1.4 U X h-1) or threefold (2.1 U X h-1) this basal level. Animals infused with 2.1 U X h-1 of bovine PTH-(1-34) exhibited hypercalcemia, hypophosphatemia, a reduction in theoretical renal threshold for phosphate and an increase in 1,25-dihydroxyvitamin D plasma levels that were approximately threefold the control value. In addition, these animals demonstrated nephrocalcinosis and changes of bone histology that were typical of the findings in patients with primary hyperparathyroidism. In contrast, in animals infused at 1.4 U X h-1, plasma calcium, phosphate, and theoretical renal threshold for phosphate remained within normal limits, but plasma 1,25-dihydroxyvitamin D was increased above control, suggesting that increased activity of 1 alpha-hydroxylase may be the most sensitive index of increased PTH levels. This animal model permits sustained elevation of PTH plasma levels at basal or pathologically elevated levels and should provide an effective means by which to evaluate the consequences of chronic hyperparathyroidism on epithelial function, bone, and other organ systems.

Epidemiological-environmental study of diesel bus garage workers: acute effects of NO2 and respirable particulate on the respiratory system

Personal samples of nitrogen dioxide (NO2) and respirable particulate (RP) were collected over the shift on 232 workers in four diesel bus garages. Response was assessed by an acute respiratory questionnaire and before and after shift spirometry. Measures of exposure to NO2 and RP were associated with work-related symptoms of cough; itching, burning, or watering eyes; difficult or labored breathing; chest tightness; and wheeze. The prevalence of burning eyes, headaches, difficult or labored breathing, nausea, and wheeze experienced at work were higher in the diesel bus garage workers than in a comparison population of battery workers, while the prevalence of headaches was reduced. Mean reductions in forced vital capacity (FVC), forced expiratory volume in 1 sec (FEV1), peak flow, and flows at 50 and 75% of FVC were not obviously different from zero. There was no detectable association of exposure to NO2 or respirable particulate and acute reductions in pulmonary function. Workers who often had respiratory work-related symptoms generally had a slightly greater mean acute reduction in FEV1 and FEF50 than did those who did not have these symptoms, but these differences were not statistically significant.

On the molecular mechanism of lactoperoxidase-catalyzed H2O2 metabolism and irreversible enzyme inactivation

Lactoperoxidase-catalyzed H2O2 metabolism proceeds through one of three different pathways, depending on the nature and the concentration of the second substrate as an e- donor and/or on pH conditions. In the lactoperoxidase (LPO)-H2O2 system, at low H2O2 concentrations and/or alkaline conditions the peroxidatic cycle involves ferric LPO----compound I----compound II----ferric LPO conversion, whereas high H2O2 concentrations and/or acidic conditions favor the ferric LPO----compound I----compound II----compound III----ferrous LPO----ferric LPO pathway. The compound III/ferroperoxidase states are associated with irreversible enzyme inactivation by cleavage of the heme moiety and liberation of iron. It is likely that either singlet oxygen or superoxide and hydroxyl radicals are involved in the attack on heme iron, because inactivation correlates with oxygen production and can be decreased to a certain degree by scavengers such as ethanol, 1-propanol, 2-propanol, or mannitol. In the LPO-H2O2-I- system, the enzyme may also be inactivated by I2 generated in the course of enzymatic I- oxidation (i.e. during ferric LPO----compound I----ferric LPO cycles).

Airborne Doppler lidar measurements

This paper describes recent measurements using coherent Doppler lidars operating at a wavelength of 10.6 microm aboard the NASA Ames Convair 990. The purpose of the measurements was to obtain data on the atmospheric wind fields and the distribution of the backscatter coefficient at 10.6 microm. A description of the instruments is provided detailing the modifications incorporated following the 1981 test flights of the systems. The measurement program is outlined, and preliminary results are discussed.

Enzyme Immunoassay for Detection of Salmonella in Foods: Collaborative Study

A collaborative study was performed in 25 laboratories to validate an enzyme immunoassay (EIA) procedure utilizing 2 specific monoclonal antibodies for rapid detection of Salmonella in foods. The EIA was compared with the standard culture procedure for detection of Salmonella in 6 food types: ground black pepper, soy isolate, dried whole eggs, milk chocolate, nonfat dry milk, and raw deboned turkey, Uninoculated and inoculated samples were included in each food group analyzed, with the exception of poultry which was naturally contaminated. There was no significant difference in the productivity of the EIA and culture procedures at the 5% level for any of the 6 foods. The enzyme immunoassay screening method has been adopted official first action.

Evidence that calcitonin stimulates 1,25-dihydroxyvitamin D production and intestinal absorption of calcium in vivo

Although it is well established that parathyroid hormone and phosphate are important regulators of 1,25-dihydroxyvitamin D [1,25(OH)2D] production, it remains unclear whether calcitonin affects vitamin D metabolism in vivo. Experiments were performed in the rat to determine the effect of chronic calcitonin infusion (0.2 U X h-1) on plasma levels of vitamin D metabolites and on calcium metabolism. Thyroparathyroidectomized animals fed a calcium-replete or calcium-free diet were studied for as long as 2 wk before they were killed. In control rats, a calcium-free diet alone for 12 d resulted in an increase in 1,25(OH)2D levels from 24 +/- 5 to 139 +/- 37 pg . ml-1, P = 0.025. The infusion of calcitonin also stimulated 1,25(OH)2D levels compared with controls on a regular diet (80 +/- 17 vs. 38 +/- 6 pg . ml-1, P less than 0.05) and on a calcium-free diet (460 +/- 50 vs. 139 +/- 37 pg . ml-1, P less than 0.001). In addition, calcitonin increased plasma calcium levels in animals on a regular diet by 50%; this effect was most likely due to increased intestinal absorption of calcium, because removal of calcium from the diet markedly blunted this effect. In contrast, calcitonin administration did not significantly affect 25(OH)D plasma levels. Collectively, these data suggest that calcitonin and calcium are independent regulators of 1,25(OH)2D production and that calcitonin stimulates intestinal absorption of calcium, by increasing circulating levels of 1,25(OH)2D.

Do the American Medical Association's campaign contributions influence health care legislation?

Despite the fact that ideology and party overshadow campaign contributions as determinants of congressional voting behavior, the thesis of this study is that the American Medical Association's contributions have an important policy impact. Their donations had a significant effect on an index of three votes in 1979 in the House of Representatives. The contributions of the AMA had more of an effect than did those of the AFL-CIO. The AMA's money was related to decision-making in the Ways and Means and Energy and Commerce Committees. While the medical lobby does not dominate health care policy, its power should not be underestimated.

Disposition kinetics of cefamandole during continuous ambulatory peritoneal dialysis

Cefamandole disposition kinetics were examined in six male subjects with renal impairment who were undergoing continuous ambulatory peritoneal dialysis. Creatinine clearance values ranged from less than 1 to 11 ml/min. Cefamandole was given as a 1-g intravenous dose infused over 30 min. Cefamandole concentrations were determined in serum, urine, and dialysis fluid by a high-performance liquid chromatographic method. The following average parameter values were obtained (range): half-life, 6.1 h (4.6 to 9.7); systemic clearance, 21.9 ml/min (8.4 to 35.5); renal clearance, 11.5 ml/min (0.03 to 22.3); dialysis clearance, 0.92 ml/min (0.7 to 1.3); nonrenal clearance, 12.2 ml/min (2.9 to 27.0); volume of distribution, 0.18 liter/kg (0.09 to 0.25); steady-state volume of distribution, 0.17 liter/kg (0.09 to 0.24). Approximately 5% of the dose was dialyzed (range, 2.8 to 8.3), indicating that there is no need to supplement a dosing regimen of cefamandole due to loss by dialysis. There was a positive correlation between creatinine clearance and the terminal elimination rate constant of cefamandole (r2 = 0.41) and cefamandole renal clearance (r2 = 0.83).

Collagen concentration as a significant variable for growth and morphology of mouse mammary parenchyma in collagen matrix culture

Multicellular organoids of mouse mammary epithelium were established in culture either upon or within collagen matrices of various concentrations. Growth and tubule morphogenesis within the matrices were dependent upon the concentration of collagen, both being maximal in gels composed of 2 mg collagen/ml gel. Growth was more extensive in cultures established in gel than on gel especially at intermediate concentrations of collagen, with cell growth on gel seemingly independent of collagen concentration. Our results demonstrate that local collagen concentration can significantly affect epithelial cell growth and morphology.

Preventing mental disorders in the minority community

Studies in community mental health have noted a disproportionate incidence of mental illness in minority populations. However, it is impossible to document its true extent without a proper data base. Most of our knowledge is based on reports from institutions and social service agencies--coroner's offices, police departments, and various treatment programs. The resulting distortion of the data makes it difficult to develop prevention policies and programs. Further, the politics incurred in implementing programs in minority communities suggest that there are political barriers to providing such services. This paper examines these critical political-social factors.

Evaluation of the Andersen viable impactor for single stage sampling

A modified use of the 6-stage Andersen viable sampler for single stage sampling is described. Although size distribution data are not obtainable with such a sampler, it has utility as a simple and convenient method for estimating the total concentration of viable airborne microorganisms. The method was compared in the field to the standard Andersen sampler and a previously described method for single plate sampling. Over a wide range of airborne fungal concentrations (10-3000 CFU/m3), the modified sampler was found to be superior to the previous method and comparable to the standard Andersen sampler (in terms of both precision and accuracy), for estimating total airborne fungal concentration.

Environmental study of poultry confinement buildings

Environmental measurements were made in three poultry confinement buildings in order to characterize gas and particulate contaminants. Levels of total and respirable dust averaged 4.4 and 0.24 mg/m3, respectively. Particle size distribution as measured by cascade impactors was similar in the three confinement houses with a mass median aerodynamic diameter of about 15 microns and a geometric standard deviation of about 2.2. Ammonia levels measured in the active areas of the buildings averaged about 25 ppm. Ammonia concentration was quite high, however, in an unused and unventilated portion of one of the buildings (mean = 170 ppm). CO2 levels ranged from 0.05-0.1%. Levels of CO, H2S, NO2, NOx, CH4, mercaptan, formaldehyde, and hydrocarbons were all below the limit of detection for indicator tubes. Concentrations of airborne bacteria and fungi were on average about 1.5 X 10(5) and 1.0 X 10(4) colony-forming units/m3, respectively. Endotoxin analysis was also performed on the total and respirable dust samples. Endotoxin levels (expressed in air concentration) ranged from 0.77 to 61 ng/m3 for total dust and from 0.71 to 15 ng/m3 for respirable dust. Endotoxin was also measured on the collection media from the individual impactor stages. Endotoxin was detected in all size ranges with the highest concentration of endotoxin per unit of dust found in the smallest (less than approximately 3.5 microns) size fraction. The endotoxin levels tend to be lower than those previously reported in poultry operations.