Positive impact of home hemodialysis.

The intended patient outcomes have been achieved. Home hemodialysis has improved the quality of life for this entire family. Continuous support is necessary to help this family maintain an acceptable lifestyle. This remains a primary goal of care. The nephrology nurse proved to be the key to this successful home hemodialysis experience. Appropriate training coupled with frequent communication and encouragement resulted in a positive patient and family outcome.


Case management of the anemic patient. Epoetin alfa: focus on sexual dysfunction.

Sexual dysfunction is a common problem for patients with ESRD. This article discusses the nature of the problem, along with the improvement in sexual function that has been noted after beginning therapy with Epoetin alfa. The assessment and management of patients with sexual dysfunction are described, and the role of the nurse is emphasized.


Calcitriol injection for the management of renal osteodystrophy.

The introduction of synthetically produced calcitriol in the early 1970s was an important contribution to the prevention and treatment of renal bone disease. However, despite the efficacy and the availability of oral calcitriol many dialysis patients continued to develop secondary hyperparathyroidism (Norris, 1991). Effective treatment was often impossible in patients with osteitis fibrosa because even low oral doses of calcitriol could cause hypercalcemia (Andress, Norris, Coburn, Slatopolsky, & Sherrad, 1989). From 1981 to the present, numerous studies have been conducted that have demonstrated intravenous calcitriol as being more effective and having several advantages over the oral route of administration, particularly in patients with poor compliance and those with a tendency to develop hypercalcemia.


[Efficacy of radical treatment with halofantrine on the prevention of imported Plasmodium falciparum malaria].

We carried out in 1989 a non randomized comparative study in French army units which had been in Central Africa (Central African Republic and Gabon) for 4 months, in order to compare in 758 men on return from malaria areas the usual strategy of chemoprophylaxis with chloroquine and a radical cure by halofantrine (Halfan). Chloroquine was taken by 278 men (100 mg daily for 6 weeks after their return to France); the other 480 men were given two doses of 1,500 mg halofantrine on the third and on the tenth day after their return to France. In Africa both of the units were on chloroquine prophylaxis (100 mg daily for 4 months). The Plasmodium falciparum attack rates were, during a period of 5 months after the return to France, 0.2% in the halofantrine group (1/480) and 4.7% (13/228) in the chloroquine group (P < 10(-4)). The radical cure by halofantrine was more effective than chloroquine prophylaxis in preventing falciparum malaria on return from malaria areas.


Screening for Trypanosoma brucei gambiense antibodies with the Indirect Fluorescent Antibody Test (IFAT). Effect of age and previous treatment.

This paper reports on some of the findings of a longitudinal multi-round investigation into the predictive power of early signs and symptoms of human African trypanosomiasis caused by T.b. gambiense, in the Rural Health Zone of Kasongo (Maniema, Zaire). It assesses the importance of the effect of age and a history of previously treated sleeping sickness on serological positivity as measured by the Indirect Fluorescent Antibody Test (IFAT), used as a screening test. The impact of including age and a history of previous sleeping sickness as part of the screening process is discussed in terms of sensitivity and positive predictive value. Including weak serological positivity among the screening criteria does not appear to improve the sensitivity of the IFAT test in this setting.


Evaluation of the cryptococcal antigen test as a diagnostic tool of AIDS-associated cryptococcosis in Rwanda.

To evaluate the latex test, two different retrospective studies were undertaken. A positive culture for Cr. neoformans was used as the golden standard of active cryptococcal infection. 439 sera selected at random sent to the NSP laboratory for screening of HIV antibody were tested as well as--71 CSF from patients with meningeal symptoms sent to the laboratory of the Centre Hospitalier de Kigali. In total, two discrepancies were found: two CSF samples from ancient cases of cryptococcosis under treatment were positive with the latex test and negative by culture. If it stands to reason that the antigen test cannot differentiate between active and inactive cryptococcal diseases, the persistence of small amounts of soluble antigens in a CSF implies that the patient must remain under surveillance, a relapse being very frequent in AIDS patients. As a conclusion, the latex test is a fast, easy to perform and quite reliable test for the diagnosis of cryptococcosis.


[Seroepidemiological study of toxoplasmosis in Libreville, Gabon].

A sero-epidemiological survey of toxoplasmosis has been carried out in 1178 subjects residing in urban and suburban areas of Libreville, Gabon. Two techniques were used: Pastorex toxo of the Institut Pasteur and ISAGA of bioMérieux. The acquisition of antibodies occurs at an early age, from the age of six months on. After the age of 15 years, the age of procreation, the prevalence is 68%. Between the ages of 15 and 19 years, 19% have IgM. The risk for toxoplasmosis acquired during pregnancy is not to be neglected. It decreases between the ages of 20 and 30 years. The most probable source of contamination is the reservoir from the soil. No difference between the sexes was observed.


[High prevalence of konzo associated with a food shortage crisis in the Bandundu region of zaire].

Konzo is a form of spastic paraparesis reported from several rural areas in Sub-Saharan Africa. It has been attributed to cyanide exposure from exclusive consumption of insufficiently processed bitter cassava roots. We have tested this attribution in a community based epidemiological survey in an area of Bandundu region in Zaire composed of two agro-ecological zones: savanna and forest. In the savanna area with poor soils we found 78 konzo cases in 1,936 inhabitants, a prevalence of 4%; but in the forest area only 9 cases in 5,531 inhabitants (0.2%). This geographical distribution as well as the temporal distribution coincide with frequent short-soaking of cassava roots (only one night) induced by an agro-ecological crisis. High levels of blood cyanide, mean 13.3 mumol/l (range: 0.1-76.3) and serum thiocyanate, mean (+/- SD) 401 (+/- 126) mumol/l, in a sample of 18 subjects from the savanna area confirm high cyanide exposure in this population with high prevalence of konzo. Prevention of konzo in Zaire is possible by promotion of sufficient soaking of cassava with strict adherence to traditional three nights soaking and the use of completely dry flour.


[Population dynamics and infestation of Bulinus truncatus and Bulinus forskalii by schistosomal larvae in the Sudan-Sahelian zone of Cameroon].

The evolution of the population densities of Bulinus truncatus and Bulinus forskalii has been studied during 18 months in a number of sites of the Sudan-Sahelian zone of Cameroon, in relation to certain environmental factors. Only the altitude of the water in the sites has an influence on the density of the snails. The populations of B. truncatus present a greater proportion of young molluscs during the entire year, with the exception of the last months of the dry season. The population dynamics of B. forskalii varies depending on whether the environment is temporarily stagnant, temporarily running or stable. The proportions of B. truncatus and B. forskalii that emit cercariae of schistosomes are 1.2% and 0.8% respectively. Study of the adult worms obtained after infestation of the laboratory mammals show that B. truncatus emits cercariae of Schistosoma haematobium at the end of the dry season and at the beginning of the rainy season. We have not been able to identify precisely the cercariae emitted by B. forskalii, which raises the necessity of further systematic studies being carried out on the schistosomes of Cameroon.


[Typology and performance of first-referral hospitals in sub-saharan Africa].

This descriptive study provides a typology of first referral level hospitals in sub-Saharan Africa. Data are provided on 88 mainly non-governmental hospitals in 25 African countries. They were obtained through a mail survey. The first aspect discussed is the place of the hospital within the spatial organization of the health care district: population served and other health units. This makes it possible to classify the hospitals in three groups. The analysis of the role of the hospital in the management of the district and the support of the peripheral network is based on information about the formal relations of authority, the participation of the hospital in training and supervision, in provision of drugs and in the financial management of the district. This is followed by a description of the human and other resources available in the hospitals, the type and organization of care provided, as well as the performances in terms of outpatient care, inpatient care and technical interventions. Finally, the available information on expenditure and sources of financing is presented.


Bone tissue growth enhancement by calcium phosphate coatings on porous titanium alloys: the effect of shielding metal dissolution product.

The possible mechanism of minimization of prosthesis-derived bone growth inhibitors by shielding of the metal and the reduction, if not elimination, of the associated metal dissolution was investigated. Titanium, aluminium and vanadium release rates were determined in vitro for Ti alloy specimens both with and without a calcium phosphate coating. Ti orderly oriented wire mesh (OOWM) porous coatings on Ti-6Al-4V substrates were used as the metal specimens. Half of the specimens were coated with a 75 microns calcium phosphate ceramic (CPC coating). Seven reference (OOWM) and seven coated (OOWM-CPC) specimens were immersed and placed along with seven control solutions for various periods in an incubator maintained at 37 degrees C and 5% CO2 - air atmosphere. Whereas the reference solutions showed a Ti release increasing as a function of time, the solutions that had the CPC-coated specimens contained no measurable amounts of titanium. The Al in solution around the CPC-coated specimens was significantly greater than the concentration around non-coated specimens. The Al, however, did not increase significantly with time, at least up to 4 wk immersion. The ceramic coating had a small beneficial effect on V concentration. In the absence of a significant adverse effect of Ti on local bone tissue formation, we focus on the Al data of our study. The possible adverse effect of this element is well documented. The calcium phosphate coating produced a significant increase of biological fixation, yet at the same time a greater Al release into solution, calling into question the significance of CPC coating in shielding adverse metal passive dissolution to explain enhanced bone growth [corrected].


Using theory and basic research to target primary prevention programs: recent developments and future prospects.

This paper is concerned with recent attempts within the field of primary prevention to use theory and basic research to develop intervention programs. It starts by reviewing a number of recent large scale studies based upon the dominant theoretical perspective within this field--the social influences model. It argues that the results of such evaluations suggest that a 'universal' prevention strategy (i.e. one aimed in an undifferentiated manner at all individuals within a given population) is out of touch with our current knowledge concerning the etiological processes underlying substance use and misuse. As an alternative, it is suggested that prevention programs be developed according to a number of 'specific' strategies (i.e. ones targeted at vulnerable subgroups within larger populations). The rationale underlying this approach, as well as a number of theoretical models upon which such interventions might be developed, is then outlined.


Alcohol and the skin.

The cutaneous stigmata of chronic alcoholic liver disease have been well recognised since the nineteenth century. However, it is now clear that the skin may be affected as an early feature of alcohol misuse. In particular, psoriasis, discoid eczema and superficial infections are more common in heavy drinkers. Awareness of these early associations can alert physicians to patients at risk of future complications of alcoholism. Great advances have been made in the understanding of the physiological and pathological effects of ethanol. The implications of these changes in the skin are discussed with reference to both the new and established cutaneous signs of alcohol misuse.


Platelet paroxetine binding in alcoholics.

Platelet paroxetine binding was analysed in 24 abstinent alcoholics and 18 control persons. The alcoholics had significantly more binding sites than the control persons. Most of the alcoholics showed affective symptoms and the increased platelet paroxetine binding was predominantly observed among those who had the lowest Newcastle score, indicating the presence of non-endogenous depression.


Reduced spinal and femoral bone mass and deranged bone mineral metabolism in chronic alcoholics.

Prevalence and factors which may influence the development of osteoporosis have been assessed in 32 chronic alcoholic males by measuring the bone mineral density (BMD) of the lumbar spine and femoral neck by dual photon absorptiometry. Serum bone Gla-protein, as an index of bone formation, 25-hydroxyvitamin D, testosterone and cortisol levels were also measured. Eleven patients (34%) had osteoporosis. In seven the lumbar BMD was below the fracture threshold. Lumbar and femoral neck age-matched BMD were below mean normal values in 20 and in 23 patients, respectively. Moreover, the age-matched BMD was significantly lower in the femoral neck (91.7 +/- 14.4%) than in the lumbar spine (100.1 +/- 17.1%) (P < 0.001). Duration of alcoholism was significantly higher in patients with age-matched BMD below 100% than in those with age-matched BMD above 100%. Bone GLA-protein and 25- hydroxyvitamin D were below normal levels in 67% and 56% of patients, respectively. Serum testosterone was normal in all but two patients, and cortisol was within normal values in all patients tested. In addition a direct correlation was found between the days of abstinence before the study and serum levels of bone GLA-protein (r = 0.64, P < 0.001). In conclusion, chronic alcoholics frequently have bone loss of the lumbar spine and femoral neck related with the duration of alcohol intake. The correlation between bone-GLA protein levels and the days of abstinence suggests that alcohol directly depresses bone formation. Likewise, the low levels of vitamin D also support that this deficiency may contribute to the development of osteopenia in chronic alcoholism.


Acute inhibition of lipid transport in rat intestinal lymph by ethanol administration.

To observe the effect of acute ethanol ingestion on stable lipid transport in intestinal lymph, three groups of mesenteric lymph fistula rats were prepared. In group A rats, lipid emulsion containing 120 mumol/hr of oleate (control meal) was infused intraduodenally for 8 hr. Group B rats were infused with another lipid emulsion, which had the same basic composition as the control meal but included 0.75 g/kg body weight/hr of ethanol (alcohol meal), for 8 hr. In group C, rats were infused with the control meal for the first 4 hr, then with the alcohol meal for the next 4 hr. Lymph flow increased just after the infusion of ethanol, that is, lymph flow in group B was significantly higher than that of group A at 1 and 2 hr, and lymph flow in group C was significantly higher than that of group A at 5 hr. In group A, lymphatic triglyceride (TG) output reached a plateau of more than 30 mumol/hr after 3-hr infusion. TG output in group B was significantly lower than that in group A from 2 hr to 8 hr and was two-thirds that of group A at the plateau level. In group C, TG output was the same as in group A until 5 hr, but decreased to two-thirds of that in group A at 6 hr, 2 hr after replacing the control meal with the alcohol meal. Lymphatic phospholipid output exhibited a tendency similar to that of TG output. Comparisons of group A vs. B and A vs. C clearly demonstrated an inhibitory effect of ethanol on stable lipid transport in intestinal lymph. A 2-hr infusion was enough for ethanol to exhibit its inhibitory effect. In conclusion, stable lymphatic transport of intestinal absorbed lipid was suppressed by acute ethanol ingestion.


Imidazole dipeptides in experimental alcohol-induced myopathy.

Rats were chronically fed a nutritionally complete liquid diet containing 35% of total calories as either ethanol, or (for the controls) an isocaloric amount of glucose. After 6 weeks of treatment, the feeding regime induced skeletal muscle myopathy as characterised by reductions in muscle weight and RNA content. Ethanol preferentially affected the metabolically glycolytic plantaris (Type II fibre-predominant) muscle of the rat, compared with the metabolically oxidative soleus (Type I fibre-predominant). The changes in the plantaris were associated with increases in the concentration (mumol per g wet weight) of anserine (18%) and carnosine (50%). No significant changes were seen for the concentrations of either anserine or carnosine in the soleus muscle. The total contents (mumol per muscle) of carnosine and anserine in the plantaris were not significantly altered by ethanol treatment, though a significant decrease in anserine content (30%) occurred in the soleus. It is concluded that reductions in imidazole dipeptide content, considered to be antioxidants and/or intracellular buffering agents, are not mediating factors in the development of chronic experimental myopathy.


Kinetics of ethanol and methanol in alcoholics during detoxification.

We investigated the kinetics of ethanol and methanol in 20 dependent alcoholics (16 men and four women) during the first 24 hr after admission to hospital for detoxification. The blood-ethanol concentration (BEC) on admission ranged from 238 to 489 mg/dl (mean 386 mg/dl). The mean rate of ethanol disappearance from the blood was 23 mg/dl/hr with a spread from 13 to 36 mg/dl/hr. The concentrations of methanol in blood at the start of detoxification ranged from 0.16 to 2.8 mg/dl (mean 1.15 mg/dl) and these levels remained more or less unchanged until the BEC had dropped below 30 mg/dl. The concentrations of ethanol and methanol in blood at the start of detoxification were not correlated (r = 0.032, P > 0.05). The results of this study do not support the notion that the metabolism of methanol in chronic alcoholics proceeds independently of the prevailing BEC. We found a three-fold difference in the rate of disappearance of ethanol from blood in alcohol-dependent subjects.


A randomized study of long-term out-patient treatment in alcoholics. Psychiatric treatment versus multimodal behavioural therapy, during 1 versus 2 years of treatment.

Seventy-two alcoholic patients (60 men and 12 women) were randomized into four groups who received psychiatric treatment (PT) or multimodal behavioural therapy (MBT), for either 1 or 2 years. PT was based on psychodynamic principles, and MBT is a cognitive-behavioural treatment. The patients accepting treatment had a mean age of 37 +/- 9 years, and they were socially stable. There was no difference in attrition rate (35%) in relation to therapy and length of treatment. The rate of favourable drinking outcome during the third year was similar in all four alternatives, at 40-44%. A favourable drinking outcome was predicted by a better initial psychic status and few psychiatric symptoms at intake. In PT patients a favourable outcome was more strongly related to a better psychic status than in MBT patients (P = 0.58). The mean number of sessions, 23, did not differ in relation to outcome. The main conclusion from this study is that there were only small and inconclusive differences between the therapies of different types and different duration.


Physician's information about alcohol problems at hospitalisation of alcohol misusers.

Information was gathered on recognition and treatment of alcohol problems in the primary and secondary health sectors, the latter represented by a department of hepatology. The general practitioner finds in most cases (18/26, 69%) that it is relevant to advise about a patient's alcohol misuse on admission forms when the patient previously has been discharged from another department with this diagnosis. However, if the patient has not previously been hospitalised due to alcohol misuse, information on the diagnosis is only rarely (30/114, 26%) available. This difference is highly significant (P = 0.0001). The case-recording hospital physician at admission recognises 73% of alcohol misusers who are admitted with a non-alcohol-related diagnosis. When the patient had been evaluated by both the admitting physician and the case-recording hospital physician, information on the alcohol problem occurred significantly less often in female compared to male patients (75% vs. 94%; P < 0.002). Only 42 of 208 (20%) of alcohol misusers were under treatment with thiamine/B-vitamins and/or disulfiram before admission. There was a significant difference (P < 0.003) as to whether the patient was treated when the general practitioner wrote alcohol misuse on the admission form and when he did not (37% vs. 10%). At admission, treatment was begun in 54%, and by the discharge 78% were under treatment. Further quality assurance in the diagnosis and treatment of patients with alcohol problems is needed.


A descriptive study of alcohol-dependent women attending Alcoholics Anonymous, a regional council on alcoholism and an alcohol treatment unit.

A total of 86 women, attending three different agencies, were interviewed on their help-seeking behaviours for problem drinking. Each agency represented a different type of help available in the community. Self-help was represented by Alcoholics Anonymous; the non-statutory sector by a regional council on alcoholism's offices; and the statutory sector by an alcohol treatment unit's out-patient department. Differences between the groups in terms of demography and drinking history are explored in this paper. It was found that the regional council group resembled the female problem drinkers in other alcohol treatment agencies in terms of alcohol dependency, pattern of alcohol consumption and drinking styles, but differed in age and abstinence behaviour.


Old and new MMPI-derived scales and the short-MAST as screening tools for alcohol disorder.

Ten previously published and two new MMPI-derived scales were compared with the short-form of the Michigan Alcohol Screening Test (SMAST-13) in terms of sensitivity and specificity at detecting alcohol disorder in a study of 100 alcohol out-patients, 100 mental health out-patients, and 100 college students. The SMAST-13 and the new MMPI-derived alcoholism scales performed best at detecting alcohol disorder on multiple criteria including the standard contingency table, relative efficiency, and receiver operator characteristic analyses. These conclusions, were found to be robust in separate analyses for males and females.


Operational definitions of alcohol dependence and associated factor structures.

This paper examines the impact of three different operational definitions of alcohol dependence on analyses of the factor structure of that concept. Data came from a sample of 219 men interviewed while in treatment for alcohol problems. The first operational definition was created with 20 items previously used in the literature and which are thought to represent the elements of dependence in the DSM-III-R criteria. In the second operational definition, the 20 items composing the first definition are combined under each of nine elements approximating the DSM-III-R criteria and thus analyzed. Finally, in the third operational definition, rather than using traditional items, the elements of the syndrome are defined by new items with wording close to that found in the DSM-III-R criteria. Results show variations ranging from a dual factor to a five-factor structure depending on the operational definition being analyzed.


Artificial intelligence in automated classification of rat vaginal smear cells.

Microscopic examination of vaginal smears has been used routinely to determine the stage of the estrous cycle of female rats in reproductive research. The stage of the estrous cycle is based on relative counts of nucleated epithelial cells, cornified epithelial cells and leukocytes. The purpose of this project was to explore automation of vaginal smear analysis using image processing and artificial intelligence techniques. A fully connected back-propagation neural network was used to locate all potential objects in a digitized scene. A unique algorithm was then employed to center a subsequent sampling box to collect pixel intensity values from the red and green components of each image. A final neural network was used in the classification of cell type. Neural networks were used because of their ability to generalize among input patterns and to tolerate extraneous noise due to variations in staining artifacts and aberrant illumination of the microscope field. This preliminary cell diagnosing system not only provides the basis for the fully automated system but also provides a method by which many other cytologic image processing problems can be automated.


Bayesian belief networks in quantitative histopathology.

Bayesian belief networks have a dynamic range and numeric response characteristics that make them uniquely suitable for descriptive classification schemes. Features showing considerable overlap of tolerance regions may be used, in a cumulative manner, to derive unequivocal classification decisions. The numeric response characteristics of Bayesian belief networks are analyzed, and their application as control modules in automated scene segmentation in histopathology is demonstrated.


Comparison of nuclear shape in aspirated and histologic specimens of prostatic carcinoma.

Nuclear shape analysis of histologic sections of operative specimens has separated patients with clinically localized prostatic carcinoma with good and poor prognoses. In order to become more useful clinically, nuclear shape should be evaluable preoperatively but is distorted by core biopsy. We used nuclear morphometry to compare histologic and cytologic specimens obtained from 20 patients who underwent radical prostatectomy for clinically localized prostatic carcinoma. Neoplastic nuclei from cytologic aspirates prepared by the Papanicolaou and Diff-Quik techniques and standard histologic sections stained with hematoxylin and eosin were digitized. Air-dried nuclei of the Diff-Quik preparation had a nuclear area of 104.2 microns 2 +/- 28.2 SD. These nuclei were nearly twice as large (paired t test, P < .001) as in the Papanicolaou (55.6 +/- 13.0 microns 2) and histologic (55.8 +/- 12.7 microns 2) preparations. However, nuclear shape was not affected. Nuclear roundness factor (deviation from circularity) and boundary curvature were similar (paired t tests, P > .05). All nuclear shape descriptors of cytologic smears fell within intraobserver variations of measurements in histologic sections. Nuclear shape is not altered in Papanicolaou- and Diff-Quik-stained cytologic specimens and should be tested for preoperative assessment of outcome in clinically localized prostatic carcinoma.


Syntactic structure analysis of the arrangement of nuclei in dysplastic epithelium of colorectal adenomatous polyps.

In search of new objective classifiers of the degree of dysplasia in colorectal adenomatous polyps, we conducted syntactic structure analysis on hematoxylin-eosin-stained tissue sections of 59 colorectal adenomas. The adenomas were subjectively graded as showing mild (n = 20), moderate (n = 20) or severe (n = 19) dysplasia in a double-blind examination by two pathologists. Using an interactive video-overlay measuring system, a minimum spanning tree was computed in 10 fields per specimen according to a strict measurement protocol. From each minimum spanning tree, such features as total line length, length of line segments, total number of points and number of points with one, two, three or four neighbors were derived. Simple descriptive statistics of these minimum spanning tree features were used to analyze differences between the three grades of dysplasia. Univariate analysis indicated that most of the variables used were suitable for discriminating between mild and moderate as well as between mild and severe grades of dysplasia. Only median minimum line length also showed significant differences between moderate and severe dysplasia. By means of a jackknifed stepwise discriminant analysis, an overall correct classification of mild versus moderate and severe dysplasia of 81.4% was achieved. It is concluded that syntactic structure analysis may have additional value in describing, in an objective and rapid way, the morphologic changes of dysplasia in colorectal adenomatous polyps.


Interactions between dental amalgams and the oral environment.

Dental amalgam fillings interact in a complex way with the environment in the oral cavity as they are subjected to chemical, biological, mechanical, and thermal forces. These forces change the restoration's appearance and properties, while metal ions, amalgam debris, non-metallic corrosion products, and mercury vapor are released into the oral cavity. The phenomena and conditions that affect the amalgam/environment interaction include the chemistry and biochemistry of the environment, formation of biofilms on the amalgam surfaces, existence of localized corrosion cells, galvanic contacts with other metallic restorations, abrasion during mastication, and synergistic effects of the different forces. Corrosion processes result in a degradation of the functional amalgam properties, while tarnishing reactions cause discoloration. Corrosion degradation of amalgam fillings is due mainly to localized corrosion cells in pores and crevices. Corrosion on occlusal surfaces is accelerated by abrasion during mastication, which removes the protective surface films. The average total amounts of metal species, including mercury, released per day in vivo from a restoration have not been determined. Much of the reported indirect evidence for high mercury release rates is either unreliable or controversial. A more detailed investigation is needed and will require the development of more sophisticated techniques of sampling in vivo, as well as both experimental and theoretical modeling in vitro.


Side-effects: mercury contribution to body burden from dental amalgam.

The purpose of this paper is to examine and report on studies that relate mercury levels in human tissues to the presence of dental amalgams, giving special attention to autopsy studies. Until recently, there have been few published studies examining the relationship between dental amalgams and tissue mercury levels. Improved and highly sensitive tissue analysis techniques have made it possible to measure elements in the concentration range of parts per billion. The fact that mercury can be absorbed and reach toxic levels in human tissues makes any and all exposure to that element of scientific interest. Dental amalgams have long been believed to be of little significance as contributors to the overall body burden of mercury, because the elemental form of mercury is rapidly consumed in the setting reaction of the restoration. Studies showing measurable elemental mercury vapor release from dental amalgams have raised renewed concern about amalgam safety. Mercury vapor absorption occurs through the lungs, with about 80% of the inhaled vapor being absorbed by the lungs and rapidly entering the bloodstream. Following distribution by blood circulation, mercury can enter and remain in certain tissues for longer periods of time, since the half-life of excretion is prolonged. Two of the primary target organs of concern are the central nervous system and kidneys.


Teratological aspects of dental amalgam.

The teratogenic effect is determined by four factors: (1) the agent, (2) the dose, (3) the stage of embryonic development, and (4) the genetic constitution of the embryo. The first two factors are of particular interest and warrant further comment. It should be emphasized that the mercury released from dental amalgam is mainly metallic mercury vapor. The dose of mercury vapor from dental amalgam fillings in the order of 5 micrograms/day is very low compared with the doses in a teratological study and is not likely to exceed the threshold necessary for a teratogenic effect to occur. The concentration of the teratogen at the target tissue is determined not only by the degree of placental transfer but also by other factors, such as the distribution within the maternal organism, the affinity to the fetal liver and blood, the hematocrit value, and the passage through the ductus venosus. These factors might help to explain toxicological mechanisms and species differences and have to be considered if the results of animal experiments are to be extrapolated to human conditions. Neither epidemiological data nor animal experimental data indicate that the release of metallic mercury vapor from dental amalgam therapy should cause teratogenic effects. A comparison with the incorporation of the fetotoxic methyl mercury might be justified.


Oral mucosa and skin reactions related to amalgam.

Documented cases of oral mucosa and skin affections related to amalgam restorations are rare, although the exact incidence is unknown. Lesions of the oral mucosa may be due to specific immunologic or non-specific toxic reactions toward products generated from restorations. The immunologic reaction most probably involved in mucosal affections related to amalgam is the delayed or cell-mediated (type IV) reaction. Such reactions are seen in contact allergy, and the term "contact lesions of the oral mucosa" has been used. There is a much lower tendency of sensitization through mucous membranes than through skin, and it is questionable whether mercury released from amalgam restorations is able to sensitize a patient. A chronic toxic reaction may be established due to repeated or constant influence to toxic agents in low concentrations over long periods. Such reactions are most frequently localized to the contact zone with the toxic agent. Chronic toxic reactions may possibly be seen in areas of the oral mucosa in direct contact with amalgam fillings. Since the clinical features of these lesions do not differ from those of lesions due to contact hypersensitivity, the diagnosis is obtained by exclusion based on a negative patch test.


Dental amalgam--environmental aspects.

Increasing knowledge about the risk of toxic effects caused by anthropogenic mercury accumulation in ecosystems has resulted in a growing pressure for reduction of the discharge of mercury waste. Consequently, the mercury waste problems of dental clinics have been given increased attention, and restrictions on handling and discharge of contaminated waste have been established in several countries. Major amalgam particles from trituration surplus of those produced during the carving and burnishing of new amalgam restorations are generally collected in coarse filters and sold for refinement. Minor amalgam particles released by production of new fillings or by removal of old restorations partly sediment in tubes and drains. The remaining particles are carried with the waste water stream to the local purifying plant. In Scandinavia, the industrial discharge of mercury-contaminated waste water has been reduced to a minimum. According to recent investigations, dental clinics appear to be responsible for the major amount of mercury collected in the sludge generated in purifying plants. If threshold values for heavy metal content, including mercury, are exceeded, the sludge is not allowed to be recycled as fertilizer. Installation of an approved amalgam-separating apparatus in dental clinics is now mandatory in several countries--for example, Switzerland, Germany, Sweden, and Denmark. Approval of amalgam separators is based on national testing programs, including clinical or laboratory tests demanding 95-99% separating efficiency.


Documented clinical side-effects to dental amalgam.

Since all dental restorative materials are foreign substances, their potential for producing adverse health effects is determined by their relative toxicity and bioavailability, as well as by host susceptibility. Adverse health effects to dental restoratives may be local in the oral cavity or systemic, depending on the ability of released components to enter the body and, if so, on their rate of absorption. The medical scientific community is now in general agreement that patients with dental amalgam fillings are chronically exposed to mercury, that the average daily absorption of mercury from dental amalgam is from 3 to 17 micrograms per day, and that the amalgam mercury absorption averages 1.25-6.5 times the average mercury absorption from dietary sources (World Health Organization, 1991). The health significance of this chronic mercury exposure is now being investigated by several medical research groups.


Dental amalgam and mercury vapor release.

Dental diseases are among the most common ailments, and dentists in the United States spend over 50% of their time in dental practice rebuilding carious, malformed, and traumatically injured teeth. It is logical, therefore, that the majority of the dental school curriculum is devoted to the diagnosis, prevention, and treatment of teeth with anomalies. Dentists have several choices of materials they can use to accomplish the task of rebuilding teeth. Besides amalgam, they have ceramic materials, resin composites, base-metal and noble casting alloys, and glass-ionomer cements to use to restore the posterior dentition. Each of these restorative materials has advantages and disadvantages, and the clinical judgment as to when a particular material should be used is given a high priority in dental education. Amalgam is the most widely used of these restorative materials, with 92% of dentists listing it as the material of choice in the posterior of the mouth (Clinical Research Associates, 1990). Dentists have been placing amalgams for over 150 years in the US. They placed 150 million last year, which represents over 75 tons of amalgam alloy. The reasons that dentists use this restorative material so frequently are its durability, ease of manipulation, and low cost. Numerous clinical studies have been conducted on the serviceability of amalgam. Most of these have been on the old, low-copper alloys, and results indicate that they last from 8 to 15 years (Bailit et al., 1979; Osborne et al., 1980; Qvist et al., 1986). In the past 20 years, vast improvements have been made in amalgams with the development of the high-copper systems.(ABSTRACT TRUNCATED AT 250 WORDS)


Toxicology versus allergy in restorative dentistry.

The frequency of side-effects among dental patients is very low and is seen mostly as mild allergic reactions. Among the dental staff, contact allergic eczema is occasionally seen, induced by certain metals and various organic materials.


Principles of risk assessment.

This review discusses the basic principles of risk assessment as used in general toxicology and in monitoring side-effects of therapeutic treatments. It also outlines how these principles may apply to assessment of biological reactions to dental restorative materials. Mercury exposure from amalgam fillings is used as an example. The calculations performed are intended only as illustrations, and many other factors must be taken into account. Thus, the calculations are not intended as the last word in risk assessment of amalgam fillings.


Biodegradation of restorative metallic systems.

Metallic materials utilized for the construction of intra-oral and implant dental restorations include a wide range of relatively pure metals and multicomponent alloys. Basic corrosion and biodegradation properties of these alloys have been studied by both in vitro and in vivo techniques. These property characteristics have been shown to be dependent on composition and metallurgical state, combinations within a construct, surface conditions, mechanical aspects of function, and the local and systemic host environment. The susceptibility of these metallic materials to various forms of biodegradation will be presented, with emphasis on corrosion.


Casting alloys: side-effects.

Side-effects from dental materials are a minor problem, but should be recognized. In recent questionnaire surveys about side-effects, the incidence was estimated to be 1:300 in periodontics and 1:2600 in pedodontics. None of these reactions was related to dental casting alloys. In prosthodontics, the incidence was calculated to be about 1:400, and about 27% were related to base-metal alloys for removable partial dentures (cobalt, chromium, nickel) and to noble/gold-based alloys for porcelain-fused-to-metal restorations. The complaints consisted of intra-oral reactions (such as redness, swelling, and pain of the oral mucosa and lips), oral/gingival lichenoid reactions, and a few instances of systemic reactions. In orthodontics, the incidence was 1:100, and most reactions (85%) were related to metal parts of the extra-oral anchorage devices. Even though the extensive use of base-metal alloys has been of major concern to the dental profession, relatively few case reports substantiate this concern. Allergy to gold-based dental restorations has been more commonly reported. Palladium-based alloys have been associated with several cases of stomatitis and oral lichenoid reactions. Palladium allergy seems to occur mainly in patients who are very sensitive to nickel. All casting alloys, except titanium, seem to have a potential for eliciting adverse reactions in individual hypersensitive patients. Tolerance induction may be a possible benefit of the use of intra-orally placed alloys. In non-sensitized individuals, oral antigenic contacts to nickel and chromium may induce tolerance rather than sensitization. A variety of systemic diseases and reactions has been claimed to be caused by dental materials. The claims are generally poorly documented.


Future needs for dental restorative materials.

While the population of the United States increases from 250 to 310 million people, the number in older age groups will increase dramatically from 28 million to about 64 million. Tooth retention has improved remarkably in the 65-74 age groups, from 7.4 in 1962 to 17.9 in 1986. While younger age groups will require less treatment due to decline in dental caries, older age groups appear to require more treatment than did similar age cohorts in previous generations. Hence, the need for restorative procedures by the United States population will be on an upward trend for the next decade or two.


Dental composites/glass ionomers: the materials.

Most commercial dental composites contain liquid dimethacrylate monomers (including BIS-GMA or variations of it) and silica-containing compositions as inorganic reinforcing filler particles coated with methacrylate-functional silane coupling agents to bond the resin to the filler. They also contain initiators, accelerators, photo-initiators, photosensitizers, polymerization inhibitors, and UV absorbers. Durability is a major problem with posterior composites. The typical life-span of posterior composites is from three to 10 years, with large fillings usually fewer than five years. Polymerization shrinkage and inadequate adhesion to cavity walls are remaining problems. Some pulp irritation can occur if deep restorations are not placed over a protective film. Some have advocated the use of glass-ionomer cement as a lining under resin composite restorations in dentin. The concept of glass-ionomer cements (GICs) was introduced to the dental profession in the early 1970's. Current GICs may contain poly(acrylic acid) or a copolymer. Higher-molecular-weight copolymers may also be used to improve the physical properties of some GICs. Stronger and less-brittle hybrid materials have been produced by the addition of water-soluble compatible polymers to form light-curing GIC formulations. The ion-leachable aluminosilicate glass powder, in an aqueous solution of a polymer or copolymer of acrylic acid, is attacked by the hydrated protons of the acid, causing the release of aluminum and calcium ions. Salt bridges are formed, and a gel matrix surrounds the unreacted glass particles. The matrix is adhesive to mineralized tissues. Provisions must be made for maintenance of the water balance of restorations for the first 24 hours.(ABSTRACT TRUNCATED AT 250 WORDS)


Biodegradation of dental composites/glass-ionomer cements.

Studies of the degradation processes, types of tests, and measurements and analyses of substances leaching out from resin-based composite materials and glass-ionomer cements are reviewed. For both types of materials, the initial release rate rapidly decreases to a low, but nearly constant, level. For composites, various types of degradation processes have been demonstrated. Elements from filler particles and degradation products from the resin (e.g., formaldehyde) leak out. Many substances are not properly identified. It is, however, difficult for in vitro and in vivo degradation to be compared. For glass ionomers, a total disintegration of a surface layer is observed, together with a slow release of elements from the bulk. Of the elements released, fluoride is the most interesting. Marked differences have been shown between in vitro and in vivo solubility tests.


Local and systemic responses to dental composites and glass ionomers.

For many years, the dental profession worked mainly with rather inert restorative materials that had a limited contact with vital tissue, and the opportunity for local and systemic complications was minimal. However, conditions have changed in recent years where the two leading non-mercury-containing materials, resin composites and glass-ionomer cements, are chemically active compounds and can have detrimental effects on pulp tissue. With the advent of light-curing techniques with incremental layering, resin component formulae that were formerly found to be quite irritating to the pulp have become less so with the elimination of the need for matrices and pressure for good adaptation to be gained. As experience revealed the deficiencies and dangers of ultraviolet-light-curing techniques, visible-light-curing systems were developed that provided greater depth of cure, a higher degree of polymerization with less shrinkage with incremental layers, and less porosity. When glass-ionomer cements (GICs) were first introduced, with just one acid (polyacrylic), pulpal responses were classified as bland. With the addition of many more acids to enhance certain characteristics and reduce the setting time, GICs have become more irritating, especially when used as luting agents in areas where the remaining dentin thickness is 0.5 mm or less. Gold foil and amalgam are inert and innocuous restorative materials but require pressure for condensation which creates an exaggerated inflammatory response. This presentation emphasizes the pulpal responses and side-effects of these non-mercury-containing restorative materials and how to keep them within an acceptable range of biocompatibility. Despite the lack of any substantial appearance of soft tissue and systemic responses to resin composites and GICs, the results of a survey of recent literature are included.


Dental composites/glass ionomers: clinical reports.

Composites and glass ionomers have not been extensively tested in clinical trials for biological safety. Most clinical evaluations have looked at other factors, such as retention, wear, or color. The primary evaluation criterion used in clinical trials is post-operative sensitivity. Sensitivity does not seem to have any correlation to pulpal inflammation. Inflammation can be the result of mechanical, thermal, chemical, and bacterial insults. It is complicated for individual contributions to be separated in short-term studies. General usage of these materials over about 20 years indicates a high benefit-to-risk ratio. Despite some complaints of sensitivity with some glass-ionomer compositions, both composites and glass ionomers are relatively trouble-free. There is no evidence of short-term or long-term risk. Toxicological studies have focused almost exclusively on pulpal reactions. Systemic reactions have not been closely examined, although there is no suspicion of any problems after virtually billions of procedures in the United States. New glass-ionomer cements are similar to contemporary composite formulations. Continued development of these materials may ultimately produce an amalgam replacement material that is economically and philosophically desirable to general dentists.


Problems and benefits associated with restorative materials: side-effects and long-term cost.

The paper reviews data on biological side-effects of dental materials on patients and also on personnel who routinely handle the materials. The incidence of adverse effects is low--in one study indicated to be 1:700 for all types of treatments. For individual types of materials, it will be significantly lower, and for restorative materials, probably in the 1:10,000 to 1:20,000 range. Allergic reactions are the most common type of adverse effect of dental materials. Lichenoid reactions on the oral mucous membrane adjacent to amalgam restorations are the most frequently encountered side-effects for a specific group of restorative materials. Cost analyses were based on reports of longevity of different restorations and the cost of restorations at the time of placement. Amalgam restorative therapy was more cost-effective than composite restorations and gold castings.


Dental ceramics: the state of the science.

This review covers the properties of dental ceramics. Castable systems, bioactive glass, PMF systems, CAD/CAM, and ceramic brackets in orthodontics are briefly discussed. Many of the advances made between 1960 and 1975 were directed toward the understanding, controlling, and developing of new ceramic processes. New and deeper understanding of the structure of non-crystalline solids, structural imperfections, sintering physics, and other physical phenomena related to the melting and solidification processes has brought ceramics from the near-total art form process of the mid-century to the status of a highly sophisticated science it enjoyed in the 1980's.


Degradability of dental ceramics.

The degradation of dental ceramics generally occurs because of mechanical forces or chemical attack. The possible physiological side-effects of ceramics are their tendency to abrade opposing dental structures, the emission of radiation from radioactive components, the roughening of their surfaces by chemical attack with a corresponding increase in plaque retention, and the release of potentially unsafe concentrations of elements as a result of abrasion and dissolution. The chemical durability of dental ceramics is excellent. With the exception of the excessive exposure to acidulated fluoride, ammonium bifluoride, or hydrofluoric acid, there is little risk of surface degradation of virtually all current dental ceramics. Extensive exposure to acidulated fluoride is a possible problem for individuals with head and/or neck cancer who have received large doses of radiation. Such fluoride treatment is necessary to minimize tooth demineralization when saliva flow rates have been reduced because of radiation exposure to salivary glands. Porcelain surface stains are also lost occasionally when abraded by prophylaxis pastes and/or acidulated fluoride. In each case, the solutes are usually not ingested. Further research that uses standardized testing procedures is needed on the chemical durability of dental ceramics. Accelerated durability tests are desirable to minimize the time required for such measurements. The influence of chemical durability on surface roughness and the subsequent effect of roughness on wear of the ceramic restorations as well as of opposing structures should also be explored on a standardized basis.


Dental amalgam: the materials.

The goal of this presentation is to describe the material as it is used clinically, explain why small quantities of Hg can be released, and suggest ideas for amalgams that do not release mercury. A set amalgam is a dynamic material that undergoes many microstructural changes during clinical use, related to both the elevated temperature and corrosion-prone environment in the mouth and mechanical forces applied to the restoration. Amalgams can be divided roughly into two groups by their copper content: low Cu (traditional) and high Cu. High-Cu amalgams generally perform better clinically, but all amalgams corrode to some extent in the mouth. Some corrosion is deemed to be a positive factor, because corrosion product deposition reduces leakage at the margins of restorations; that is, the restorations are partly self-sealing. One of the reasons cited for the improved clinical performance of high-Cu amalgams over low-Cu amalgams is that the corrosion-prone phase, gamma 2, is nearly eliminated in high-Cu amalgams. Future research should involve improvements in the clinical performance of dental amalgams, studies of the mercury release from various types of amalgams and the toxic potential of this exposure, and the development of new amalgam systems that reduce the mercury exposure. Although the longevity of modern amalgams is impressive, it is important for their stability to be increased both clinically and microstructurally. An amalgam should be developed with a stable microstructure that, once set, would not change during clinical use. Microstructural changes lead to clinical deterioration. A stable system would not corrode, and the matrix transformation gamma 1 to beta 1 would be prohibited.(ABSTRACT TRUNCATED AT 250 WORDS)


New perspectives in the differentiation of bone-forming cells.

Bone formation comprises a complex but ordered sequence of events which involves the proliferation and differentiation of chondrogenic and osteoblastic precursor cells ultimately leading to the formation of a calcified extracellular matrix. This process can be observed in vivo but under these conditions is difficult to study at the molecular level. A number of in vitro models have been developed which recapitulate discrete elements of this process. Using these models, detailed information has been obtained regarding the differentiation of bone forming cells and the molecular biology of the mineralization process. It has been shown that, in vitro, osteoblastic precursor cells can form a mineralized matrix similar to that seen in vivo. This calcification process was shown to consist of three interdependent phases: proliferation, matrix maturation and mineralization. Each of these phases was characterized by the expression of particular genes. Osteoblast precursors have been cloned and consequently shown to be able to differentiate in vitro into a number of other mesenchymal cells, supporting the theory that osteoblasts are derived from multipotent mesenchymal cells. It is possible that markers derived from these models could be used in the future to extend our knowledge of bone formation in vivo.


Interleukin-11 and its receptor.

Interleukin (IL)-11 is a bone marrow fibroblast derived cytokine with a wide spectrum of activities in different biological systems. It has been shown that IL-11 supports the growth of certain types of plasmacytoma and hybridoma cells, enhances antigen-specific antibody responses, synergizes with IL-3 in supporting megakaryocyte colony formation, acts synergistically with IL-3 in shortening the G0 period of early progenitors, induces the synthesis of acute phase proteins, and inhibits lipoprotein lipase activity and adipocyte differentiation. The human IL-11 gene, which is localized at 19q13.3-13.4, consists of five exons and four introns. Initial biochemical characterization has identified a 151 kDa protein as the potential IL-11 binding subunit of the receptor complex. Because of the overlapping biological activities between IL-6 and IL-11, we compared the signal transduction pathways mediated by IL-6 or IL-11 in cell lines responsive to both cytokines. Results from protein tyrosine phosphorylation and immediate response gene expression suggest that there are convergent and divergent points along the signal transduction pathways utilized by IL-6 or IL-11. The IL-6 signal transducer, gp130, appears to be involved in the IL-11 mediated signaling. Other cytokines such as leukemia inhibitory factor, oncostatin M and ciliary neurotrophic factor have also been shown to utilize gp130 as a signal transducer. The significance of growth factor sharing common biological activities and signaling pathways will be discussed.


Iron metabolism in Pseudomonas: salicylic acid, a siderophore of Pseudomonas fluorescens CHAO.

Under iron-starvation conditions of growth, Pseudomonas fluorescens CHA0, a soil isolate involved in phytopathogenic fungi antagonisms, produced, together with pyoverdine, a second iron-chelating compound which was purified and identified by spectroscopy, HPLC and 1H-NMR to be salicylic acid. Mutants unable to synthesize pyoverdine overproduced this compound by a factor of 9-14. The biosynthesis of salicylic acid was under iron control; it was fully inhibited by 5 microM added iron in the growth medium. In contrast, salicylic acid of either bacterial or commercial origin facilitated labeled iron incorporation in iron-starved cells. Based on these two relationships observed with bacterial iron metabolism it is concluded that salicylic acid has a siderophore function for this strain.


The effect of selenium on the function of the anion transporter (Band 3) of erythrocyte membranes.

The transport activity of Band 3 of spectrin-stripped inside-out erythrocyte membrane vesicles (IOVs) or resealed ghosts was enhanced in the presence of trace amounts of Na2SeO3 (0.2-0.5 p.p.m.); however, at higher concentrations of Na2SeO3 (> 4.0 p.p.m.), an inverse result was obtained. Reassociation of spectrin with IOVs has no effect either on the transport activity of Band 3 or on the enhancement of its activity by Na2SeO3. Sulfhydryl reagents (p-chloromercuribenzoic acid and N-ethylmaleimide) could also inhibit Band 3 activity and eliminate the selenium effect. It is suggested that SH groups are involved in anion transport of Band 3 and that the selenium effect is based on the interaction of SH groups of Band 3 with Na2SeO3.


Lipopolysaccharide-binding factors are present in bovine serum.

Response of vertebrates to bacterial lipopolysaccharide (LPS) may be regulated, in part, by serum factors that influence the bioavailability and cellular binding affinity of LPS. Using 3H- or 14C-labeled LPS, or a novel fluorescence-based assay for detection in CsCl isopycnic density gradients, our studies indicate the existence of factors in adult and fetal bovine serum that bind LPS. Within serum-containing gradients, labeled LPS appeared in two peaks: least-dense fractions (< or = 1.30 g/cm3) and at 1.35 g/cm3. This profile was different from that of gradients without serum, where LPS appeared at 1.38 g/cm3. Binding of LPS to serum component(s) at 1.35 g/cm3 was rapid (< 1 min), saturable and specific. A partial shift (50%) of LPS from a density of 1.35 g/cm3 to other serum components at < or = 1.30 g/cm3 occurred over 1 h. Flow cytometric analysis indicated that bovine serum factors influence the binding of LPS to blood monocytes, because monocyte-FITC-LPS association increased in the presence of bovine serum.


Variable alpha-tocopherol stimulation and protection of glutathione peroxidase activity in established and malignant fibroblasts.

Studies on glutathione (GSH) metabolism in an established baby hamster kidney fibroblast cell line (BHK-21/C13) and in its polyoma virus-transformed counterpart (BHK-21/PyY) have revealed a significant stimulation of intracellular GSH peroxidase (GSHpx) activity (selenium-independent plus selenium-dependent) by alpha-tocopherol supplementation (14 microM). This stimulation was found to be much greater in the transformed cells. Other GSH-requiring enzyme activities (i.e. GSH reductase and GSH S-transferase) were unaltered by alpha-tocopherol treatment, suggesting a degree of specificity in its action on GSHpx. In unsupplemented growth media, the GSHpx activity in both cell lines was significantly decreased by oxidative stress. However, the same stress applied to the alpha-tocopherol-supplemented cells had no effect on the stimulated GSHpx activity, suggesting that some protection was afforded by the alpha-tocopherol.


Effect of saffron on thymocyte proliferation, intracellular glutathione levels and its antitumor activity.

Liposome encapsulation of saffron effectively enhanced its antitumor activity towards Sarcoma-180 (S-180) and Ehrlich ascites carcinoma solid tumors in mice. Significant inhibition (P < 0.001) in the growth of these tumors was observed as compared with vehicle (control) mice. In the presence of phytohemagglutinin (PHA), a T cell mitogen, saffron stimulated non-specific proliferation of lymphocytes in vitro. The intracellular reduced glutathione and related enzymes, i.e. glutathione reductase and glutathione-S-transferase, of S-180 tumor cells were significantly elevated when incubated with saffron, possibly acting to maintain functional levels of other antioxidants. Our studies indicate the antioxidant activity of saffron.


The ability of bacteria to synthesize a new cyclopyrophosphate correlates with their tolerance to redox-cycling drugs: on a crossroad of chemotherapy, environmental toxicology and immunobiochemical problems.

Many redox-cyclers were recently shown to induce, in some bacterial species, large-scale biosynthesis of a new 2-methylbutan-1,2,3,4-tetraol-2,4-cyclopyrophosphate believed to be involved in anti-stress reactions. In the present study Mycobacterium smegmatis, Micrococcus luteus and Brevibacterium ammoniagenes were shown to begin synthesis of the new cyclopyrophosphate when cultivated in a medium containing furacilin or furadonin (widely used nitrofuran antibacterial drugs) and to maintain close to normal growth rates, whereas Staphylococcus aureus, Bacillus subtilis and Escherichia coli were inhibited by the drugs and were unable to synthesize the cyclopyrophosphate compound. Preferential binding of Mg2+ and Cd2+ with one or other phosphoryl groups of the cyclopyrophosphate, which was indicated by selective changes of 31P-NMR chemical shifts and intramolecular hydrogen bonding, is suggested as a reason for this selectivity.


[Reduced influence of penile disability on the mating capacity of male staggerer mice].

Most staggerer mutant mice do not mate spontaneously. This deficiency may be attributed to a penile disability (during erection, the penis in extension is directed backward). The main characteristics of this phenomenon and its involvement in the reproduction of the staggerer mutant have been considered in our study. Seventy-four percent (n = 66) of staggerer males presented this temporary abnormality at least once. It appeared when the males were 84 +/- 37-d old (M +/- SD). In most animals the penile abnormality was labile and did not exceed 1 wk duration in 48% (n = 32) of the males. Three males mated in spite of presenting this abnormal erection. Moreover, 25% of males (n = 23) did not present this disability; nevertheless, most of them (91%) still did not reproduce. Other mechanisms are certainly responsible for the inefficient mating. In any case, the influence of penile disability on this deficiency appears to be weak.


Ultrastructural study of nucleolar changes in rat embryos during diapause and reactivation.

Changes in nucleolar ultrastructure were studied in preimplantation rat embryos before diapause (d 5), during diapause (d 6, 7 and 8) and after reactivation brought about either by in vitro culture for 24 h (d 7 and 8) or by estradiol-17 beta treatment of the mothers (d 11). Before diapause, fully developed nucleoli contained several low-density fibrillar centers surrounded by a dense fibrillar component and an abundant granular component. This type of nucleolus indicates a high activity of ribosomal RNA synthesis. During diapause, nucleoli revealed a disorganization of the fibrillar and granular elements typical of a diminution in transcriptional activity. During reactivation, nucleoli progressively returned to a reticulo-fibrillar configuration characteristic of the onset of intense transcriptional activity. It is concluded that the structure of the nucleolus in rat preimplantation embryos corresponds to the level of transcriptional activity and is a reliable model for studying structure-function relationships during early development.


The effect of breed-type and castration on bone growth and distribution in cattle.

Data from carcasses of 210 cattle (119 bulls and 91 steers) from 4 breed types, serially slaughtered from approximately 200-800 kg kg liveweight were used to test the hypothesis of similar gender dimorphism among breeds in relation to carcass bone growth and distribution. Relative to total bone weight, breed types tended to have similar growth rates for all bones other than the cervical vertebrae, ribs, tibia and fibula, and tarsus. Adjusted to the same total bone weight there were significant differences among breed types in bone weight distribution, but the differences were very small and probably of little economic importance. Castration stimulated growth of the lumbar vertebrae, hindlimb bones, patella and hindquarter bones but inhibited growth of the ribs, scapula, carpus, forelimb bone, and forequarter bone. At the same total bone weight, steers as compared to bulls showed a shift in bone weight distribution towards the hindquarter, pistol and long bones. There were small but significant breed x gender interactions in the distribution of some bones.


The possible involvement of protein kinase C(s) and inositol phosphate metabolism in the basal but not in the prolactin stimulated casein release by the lactating rabbit mammary epithelial cell.

The secretagogue effect of prolactin (PRL) on casein release by epithelial mammary cells has been previously related to stimulation of the phospholipase A2-arachidonic acid cascade. In order to determine whether other intracellular pathways are implicated in this secretagogue effect, different agents acting on protein kinase C (PKC) and phospholipase C (PLC) activity have been assessed in vitro in lactating rabbit mammary gland fragments. Phorbol ester (20 nm TPA and 1-oleoyl-2-acetyl-sn-glycerol (10 microM (OAG) stimulated newly synthesized casein secretion and potentiated the PRL secretatogue effect. However, 100 microM quercetin, 100 microM H-7 and 5 and 20 nM staurosporine did not inhibit the latter effect. Exogenous PLC did not stimulate casein secretion. PRL did not affect production of inositol phosphates (IPs) during 10 or 60 min exposure. These results show that PKC activation may increase basal levels of casein secretion, and demonstrate that PRL does not act primarily via PKC activation or by PLC activation to stimulate casein secretion.


Intestinal transfer of manganese: resemblance to and competition with calcium.

The effect of calcium, phosphate and the sugars lactose and sorbitol on the intestinal absorption of manganese were studied in adult male rats. Gastric gavage showed that lactose (100 mM or 200 mM) increased the hepatic retention of 54Mn, while phosphate decreased it. In situ ileal loop studies indicated that Mn absorption was normally complete in 30 min. Sorbitol had no effect on uptake during this period, but extended Mn absorption from 30 min to 120 min. Low concentrations of Mn (10 microM) did not alter the enhancing effect of lactose on calcium transport (10 mM), but the enhancing effect of lactose on Mn transport was blocked by this high calcium concentration. Intestinal alkaline phosphatase activity was rapidly stimulated by Mn. These similarities plus the competition between cations, especially calcium, suggest that a common mechanism exists in their intestinal transport.


Effects of protein kinase inhibitors on pig oocyte maturation in vitro.

Normal oocyte maturation depends on signal transmission between granulosa cells and the oocyte. We have analysed the effects of inhibiting (I) cyclic AMP-dependent protein kinase (protein kinase A, PK-A), (II) Ca2+/phospholipid-dependent protein kinase (protein kinase C, PK-C) and (III) calmodulin (CaM) on pig oocyte maturation in vitro, protein synthesis and phosphorylation. The inhibition of PK-A using a specific inhibitor H8, decreased the maturation rate (rate of germinal vesicle breakdown, GVBD) of cumulus-enclosed pig oocytes in a dose-dependent manner by approximately 12%, reaching a plateau at 100 microM. The inhibition of PK-C with H7, an inhibitor with some side-effects on PK-A, decreased the maturation rate of cumulus-enclosed oocytes in a dose-dependent manner to a maximum of 20% at a concentration of 100 microM. The calmodulin antagonist W7 up to a concentration of 200 microM had no effects on maturation of cumulus-enclosed pig oocytes. None of the inhibitors (H7, H8 and W7) altered the patterns of protein synthesis of either pig oocytes and cumulus cells after maturation in vitro. Oocyte phosphoprotein patterns were, however, clearly changed by W7. Cumulus cell protein phosphorylation patterns were changed by all 3 agents. Since inhibition of cyclic AMP and Ca2+ phospholipid pathways by PK-A and PK-C blocking chemicals affected only a limited proportion of oocytes (12 and 20%, respectively) and inhibition of Ca2+ binding to CaM was without effect on oocyte maturation, we conclude that these pathways modulate rather than regulate oocyte maturation in the pig.


[Investigation on the plant origin and commodity of Chinese drug bixie].

An investigation has been made on the Chinese drug Bixie available in drug market, its folk uses and plant origin in different districts in China. The results reveal that the drug Bixie presently used in different regions in China are derived from 24 species belonging to genus Dioscorea (Family Dioscoreaceae); genus Smilax and Heterosmilax (Family Liliaceae).


[A study on suitable storage conditions for Melaphis chinensis (Bell) Baker].

It is a key procedure for breeding Chinese gallnuts to put the collected Melaphis chinensis on winter host Mnium cuspidatum. The result shows that the most suitable storage condition for the collected Me. chinensis is to store it for four days in shade before putting to winter host.


[Studies on film-covered soil setting seedling of Panax notoginseng (Burk.) F.H. Chengfu].

Film-covered soil setting seedling can markedly raise the yield of seedling and seedling establishment of Panax notoginseng, thus providing higher economic benefit. The increase of yield in trial plots was about 8.82%-24% higher than the control.


[Pharmacological studies on erzhi pills].

The experimental results show that Erzhi Pills can markedly increase the weights of immunological organs in mice and antagonize the immunosuppressive action of prednisolone. The diameter of SRID precipitating ring, the hemolytic ability of PFC and the clearance rate of i.v. charcoal particles in mice can all be increased by the pills. Erzhi Pills also protect mice from CCl4 intoxication. Steamed Ligustrum lucidum has the same action as Erzhi Pills.


[Comparison of constituents in Pueraria thomsonii Benth before and after processing].

Determinations of aqueous extract, alcoholic extract, flavonoids and puerarin as well as ten inorganic elements in Pueraria thomsonii have been made before and after processing. The results showed that the above mentioned ingredients all varied in amount.


[Analysis of active ingredients in wuren liguid].

The active ingredients and their relative concentration in Wuren liquid were analyzed by GC/MS. It has been found that there are concentrative antimicrobiological ingredients in the liquid such as phenols, benzoic acids, fatty acids, and so on. The results have confirmed the effectiveness of Wuren liquid in disinfection, germ-killing and treatment of skin diseases.


[Studies and preparations of fufang danshen granules].

With the preparation of borneol-beta-cyclodextrin inclusion compound, the stability of the product was improved. In the studies on quality standards, TLC method was used in the identification of three medicinal ingredients and TLC-ultraviolet spectrophotometry was used in the content determination of the chemical constituent tanshinone II A in Salvia miltiorrhiza.


[Diterpenoid alkaloids of Aconitum sinomontanum var. angustius W.T. Wang].

Three diterpenoid alkaloids were isolated from Aconitum sinomontanum var. angustius distributed in south Gansu. They were identified as ranaconitine (I), lappaconitine (II), 3-acetylaconitine (III) on the basis of spectral evidences (UV, IR, HNMR, 13CNMR, MS).


[Chemical constituents from the root bark of Dictamnus dasycarpus Turcz].

Rutaevin was isolated from the root bark of Dictamnus dasycarpus. It has been obtained from genus Dictamnus for the first time.


[Determination of naphthoquinone in zicao].

A TLC-spectrophotometric method for the separation and determination of the naphthoquinones in Zicao is described. The sample solution was applied at a point 1 cm from the bottom edge of a silica gel G plate. A mixture of n-hexane-acetone-chloroform-glacial acetic acid was used as the developing solvent. The plate was saturated for 30 min and developed. The spots were scraped and extracted with chloroform for spectrophotometric determination at 523nm. The method has been applied to the analysis of different samples.


[Protective effects of Panax quinquefolium saponin on oxidative damage of cultured rat cardiac cells].

When cultured cardiac cells of rats were exposed to X-XOD containing medium, the absolute values of electronic parameters were decreased the percentage of beating clusters reduced and the microscopic structure destroyed. PQS significantly converted all the indices, which shows that PQS can protect the cells from oxidative damage.


[Inotropic action of Astragalus membranaceus Bge. saponins and its possible mechanism].

Astragalus membranaceus saponins (AMS) 50-200 micrograms/ml had a positive inotropic action on the isolated working heart of rats, but in the case of 30 micrograms/ml the inotropic action turned negative. The contractility recovered after washing out the AMS. Strophanthin K performed in a similar manner as AMS. AMS 500 micrograms/ml decreased the resting potential of cultured rat heart cells by 10 mV. The results suggest that AMS plays its inotropic role through influencing the Na-K-ATPase.


A new ultrasensitive bioluminogenic enzyme substrate for beta-galactosidase.

A derivative of D-luciferin, D-luciferin-O-beta-galactoside, was synthesized and used as highly sensitive substrate for beta-galactosidase. The substrate was physicochemically characterized. Enzymatic cleavage of the new compound by beta-galactosidase was demonstrated and kinetic constants Km, Vmax, kcat and kcat/Km have been determined. The compound has been proved to be a highly sensitive substrate for beta-galactosidase, permitting a limit of detection of 3.7 x 10(-19) mol of enzyme per assay.


Partially phosphorylated glycogen phosphorylase in the lugworm Arenicola marina, its regulatory function during hypoxia.

Glycogen phosphorylase (GPase) from the body wall of the lugworm Arenicola marina (Annelida, Polychaeta) probably exists as a phospho-dephospho hybrid (GPase ab). The hybrid was identified by phosphorylation of purified lugworm GPase b (unphosphorylated form) with rabbit muscle GPase kinase and [gamma-32P]ATP. The completeness of phosphorylation was checked on DEAE-Sephacel. Only one GPase form was eluted. Its 32P incorporation was determined to 0.52 +/- 0.08 mol 32P/100,000 x g protein (n = 4). This GPase ab produced by in vitro phosphorylation has shown similar dependences on AMP and caffeine as GPase extracted from the body wall of the lugworm. Its reversible conversion with endogenous phosphatase and kinase to GPase b has also been demonstrated while a completely phosphorylated form (GPase a) was not detected neither in vivo nor in vitro. Lugworm GPase ab has shown a 2.4-fold higher specific activity as GPase b. The Km for P(i) was 16 mmol/l in absence and 13 mmol/l in presence of AMP. Half maximum activation by AMP was reached at 9 mumol/l. IMP up to 10 mmol/l did not activate and ATP up to 4 mmol/l did not inhibit GPase ab in absence of AMP.


Brain-restricted amyloidoma of immunoglobulin lambda-light chain origin clinically resembling multiple sclerosis.

Cerebral amyloid deposits restricted to the white matter and associated with intracerebral lymphoma were biochemically identified. The patient died at 58 years of age after 37 years of illness with progressive neurological symptoms clinically indicative of multiple sclerosis. Pathomorphologically, spongiform alteration and demyelinization of the white matter in the vicinity of the amyloid deposits was detected and systemic amyloidosis excluded. Immunohistochemically, the amyloid was found to be of immunoglobulin lambda-light chain origin. To establish the nature of this amyloid, its fibrils were extracted and the amyloid fibril proteins isolated by size exclusion chromatography. Immunochemically, the purified amyloid fibril proteins were shown to be of immunoglobulin lambda-light chain origin. This finding was substantiated chemically. Since the N-terminal amino acid was blocked, tryptic peptides were isolated by reversed phase HPLC. The amino-acid sequence of two major peptides revealed homology with the variable region of the immunoglobulin lambda-light chain. This report defines a novel local A lambda-amyloid disease restricted to the white matter of the brain.


Modulation of macrophage response to interleukin-2 immunotherapy by interleukin-3 in cancer patients.

It has been observed that neopterin, a specific marker of macrophage activation, increases during cancer immunotherapy with IL-2, and this effect is mediated by interferons produced by IL-2-stimulated lymphocytes. Moreover, our previous studies have shown that neopterin rise during IL-2 immunotherapy is associated with an enhanced release of soluble IL-2 receptor (SIL-2R), which may suppress IL-2-dependent immune functions. This finding would suggest that neopterin increase may be related to the generation of suppressive events, which occur during IL-2 immunotherapy. On the basis of the documented modulatory effect of IL-3 on macrophage functions, we have evaluated the influence of IL-3 on neopterin secretion during IL-2 immunotherapy. The study was performed in advanced lung cancer patients. We have investigated 9 immunotherapeutic courses consisting of IL-2 (6M IU/day s.c. for 5 days/week for 3 weeks) plus IL-3 (1 microgram/(kg x day) i.v. for 14 days, starting 7 days before IL-2). The results were compared to those found during 18 courses with IL-2 alone. Mean neopterin levels increased significantly during IL-2 alone, but not in response to IL-3 plus IL-2. SIL-2R rise was significantly higher during IL-2 than during IL-3 plus IL-2. Mean numbers of NK cells and activated lymphocytes increased significantly in both groups of patients, but were significantly lower at the end of the treatment in patients receiving IL-2 alone than in those treated with IL-3 plus IL-2.(ABSTRACT TRUNCATED AT 250 WORDS)


Cloning and sequence analyses of cDNAs encoding aminoacylase I from porcine kidney.

cDNAs encoding L-aminoacylase (EC 3.5.1.14) were isolated from a lambda gt10 cDNA library derived from porcine kidney mRNA. The clones were identified by hybridization with a synthetic oligonucleotide probe based on partial peptide sequences, or with a DNA probe encoding human aminoacylase I. Several cDNA clones isolated from the library had a length of about 1.3 kbp. They contained an open reading frame of 1218 bp encoding a polypeptide of 406 amino acids. The deduced amino-acid sequence contains the known peptide sequences; in addition, M(r) (45.3 kDa) and amino-acid composition of the predicted polypeptide match those of purified aminoacylase I. Data base searches did not reveal significant sequence homologies of aminoacylase I with other well-known amidases.


Molecular cloning of the acid sphingomyelinase of the mouse and the organization and complete nucleotide sequence of the gene.

The cDNA and complete gene encoding mouse acid sphingomyelinase (ASM) has been isolated using a homology screening approach. Comparison with the human sequence shows 81% sequence identity at cDNA level and 82% at the protein level. Homology is markedly reduced in the N-terminal region, especially in the presumed signal peptide. The six-exon gene structure is similar to the human one, except for the position of Alu1 elements. The alternatively used splice site 40 bp downstream of the human exon 2 is not conserved in the mouse gene and accordingly no such alternative splicing was found in mouse.


The properties of monoclonal antibody against sepiapterin reductase from fat body of the silkworm, Bombyx mori.

A specific monoclonal antibody prepared for the 29-kDa a subunit of silkworm fat body sepiapterin reductase (SPR) was able to recognize the subunit in crude extract of fat body after SDS treatment. Although SPR from the silkworm fat body has biochemical properties similar to those reported for SPR from mammalian sources, especially rat erythrocytes, the antibody failed to recognize the 28-kDa subunit of rat erythrocyte SPR. This result indicates that SPR from silkworm fat body has a different amino-acid sequence from that of the rat erythrocyte enzyme. Sepiapterin reductase activity has not been found in crude extract of fat body from the silkworm mutant lemon. Although the antibody recognized only 29-kDa protein in the crude extract of silkworm fat body from normal strain after SDS-treatment, the antibody recognized only an approximately 80-kDa protein in the crude extract of the lemon mutant after SDS-treatment.


Synthesis of N-acetyl-9-O-acetylneuraminic acid alpha-p-amino-phenylthioketoside and its application as ligand in the affinity chromatography of a lectin with preferential affinity to O-acetylated sialic acids.

The N-acetyl-9-O-acetylneuraminic acid-alpha-p-aminophenylthioketoside 7 was synthesized as a sialidase-stable ligand for the affinity chromatography of a lectin with preferential affinity to O-acetylated sialic acids. The thioketoside was prepared by phase-transfer-catalysed glycosidation followed by Zemplen deacetylation. Regioselective acetylation of the completely de-O-acetylated derivative was practised by two different methods. The acetylation with trimethylorthoacetate did not show the desired selectivity for hydroxyl groups; in addition to the acetylation in position 9 extensive formation of an acetimidate ester derivative with the amino-group in the aminophenyl-moiety was observed. However the esterification with N,N-dimethylacetamide dimethyl acetal resulted in an exclusive acetylation of the hydroxyl-group in position 9. After catalytic hydrogenation this ligand was immobilized both directly and by a six-carbon long spacer group to the agarose matrix. The adsorbents were applied in the affinity chromatography of the lectin and their binding capacity and selectivity compared to those of the formerly used mucin matrix. In both respects the thioketoside coupled by the spacer turned out to be a better ligand for the isolation of the lectin than the mucin.


Pteridines in the yellow-colored chromatophores of the isopod, Armadillidium vulgare.

Biochemical analyses of the dorsal integument of the isopod, Armadillidium vulgare, revealed that sepiapterin, biopterin, pterin, isoxanthopterin and uric acid accumulated in the yellow-colored chromatophores which are distinguishable from ommochrome chromatophores. The pattern of the yellow-colored chromatophores in the female is externally observable at the dorsal surface of the integument as yellow markings. In contrast, the yellow-colored chromatophores are not externally observable in the male, since they are covered by an ommochrome chromatophore layer. The content of both sepiapterin and biopterin in the male chromatophores was about two times greater than that in the female. The yellow-colored chromatophores were observable by light microscopy as pigmented granules. Electron microscopy showed that morphological properties of the granules were similar to those of pteridine granules which contain uric acid occurring in the silkworm integument. These facts indicate that both pteridines and uric acid in the integument of A. vulgare are localized in the pigmented granules of the yellow-colored chromatophores.


Intra- and interchain disulfide bridges of the human J chain in secretory immunoglobulin A.

All intra J chain disulfide bridges of human sIgA, the disulfide bonds between the J chain and the two IgA monomers, and one inter IgA monomer disulfide bridge were determined. sIgA was isolated from colostrum of healthy women and digested with IgA1-specific protease followed by cyanogen bromide cleavage. This procedure generated fragments of 140 kDa, 60 kDa, and 28 kDa. The 28-kDa polypeptide comprised the complete J chain covalently bound to two alpha 1 chain octapeptides derived from the C-termini of two alpha 1 chains. The 28-kDa fragment was digested with trypsin. The resulting peptides were purified by RP-HPLC, and subsequently characterized by amino-acid analysis, mass spectrometry, and gas phase sequencing. These data unequivocally show that the J chain cysteines C1-C6, C4-C5, and C7-C8 form intra chain disulfide bridges. The second (C2) and the third (C3) J chain cysteines are disulfide linked to two alpha chain cysteines (C17) joining the two IgA monomers of sIgA tail to tail. The remaining two alpha chains of the two monomers are directly bound to each other via their ultimate cysteines (C17-C17). A new model for the J chain in sIgA is presented.


2-hydroxy-4,4-dimethyl-2-(4-tolyl)-morpholinium bromide.

C13H20NO2+.Br-, M(r) = 302.2, monoclinic, P2(1)/c, a = 8.697 (2), b = 12.741 (3), c = 12.940 (2) A, beta = 103.39 (2) degrees, V = 1394.9 (8) A3, Z = 4, Dx = 1.439 g cm-3, lambda (Mo K alpha) = 0.71073 A, mu = 29.1 cm-1, F(000) = 624, T = 296 K, R = 0.038 for 1662 observations with I > 2 sigma (I) (of 2460 unique data). The morpholinium ring adopts the chair conformation with endocyclic torsion angle magnitudes 49.1 (4)-61.9 (4) degrees. The hydroxyl group is in the axial position of the morpholinium ring, with C--OH bond distance 1.401 (4) A. The hydroxy H atom points towards a Br ion; the interaction has O...Br distance 3.292 (2) A, H...Br distance 2.61 (3) A, and angle at H 160 (4) degrees.


Structure of 5 beta-pregnane-3 alpha, 6 alpha, 17 alpha-triol triacetate.

C27H40O7, M(r) = 476.61, monoclinic, P2(1), a = 17.440 (5), b = 13.267 (1), c = 12.168 (2) A, beta = 110.49 (8) degrees, V = 2637.3 (9) A3, Z = 4, Dx = 1.20 g cm-3, lambda (Cu K alpha) = 1.5418 A, mu = 7.04 cm-1, F(000) = 1032, T = 293 K, R = 0.048, wR = 0.068 for 5590 observed reflections with (Fo)2 > 2 sigma [(Fo)2]. The structure contains two crystallographically independent molecules in the asymmetric unit that have almost identical geometry. Rings A, B and C have chair conformations and the D ring assumes a half-chair conformation in both molecules. The progesterone side chain has a conformation typical for other 17 alpha-ester steroids; the C(16)--C(17)--C(20--O(20) torsion angles are -18.2 (5) and -15.0 (4) degrees for the first and the second molecule respectively.


Clinical evaluation of a prototype glucose electrode.

A new prototype direct reading glucose electrode working with glucose oxidase and hydrogen peroxide was preliminarily tested clinically during insulin-induced hypoglycemia in eight healthy subjects, and during hyperglycemia in five dysregulated diabetic patients. The results for 282 whole blood samples were compared to those of our routine method, which measures the glucose concentration in whole blood. The correlation was: y = 1.05.x - 0.05 mmol/L, r = 0.99. The glucose electrode measured a glucose concentration of 10.5 mmol/L +- 0.49 mmol/L (between-day imprecision) in a control serum (glucose 10.0 mmol/L). The glucose electrode supposedly responds to the activity of glucose that equals the molality (mmol glucose per kg water). The ratio of results with the glucose electrode and our routine method was lower than the expected ratio between water concentration in calibrator and whole blood, which is 1.18. A steep gradient from blood sample to glucose electrode, depending on the diffusion coefficient and hematocrit might explain the discrepancy.


In vivo evaluation of an electroenzymatic glucose sensor implanted in subcutaneous tissue.

Cleanroom processing techniques have been used to mass-produce flexible, electroenzymatic glucose sensors designed for implantation in subcutaneous tissue. In vitro characterization studies have shown the sensor's performance to be acceptable. Initial in vivo studies were conducted with the sensor implanted in the subcutaneous tissue of rabbits. Sensors implanted in the subcutaneous tissue of normal human subjects showed an excellent correlation between glucose concentrations measured by the sensor and capillary finger sticks measured with a commercial analyzer.


Fluorescent fibre-optic immunosensing system based on complement lysis of liposome containing carboxyfluorescein.

A novel type of fibre-optic immunosensing system has been developed. Agar gel-immobilized liposomes containing carboxyfluorescein were attached to the tip of an optical fibre. Complement-mediated immunolysis of the liposome was fluorometrically detected through the fibre. By using dinitrophenyl (DNP) hapten-loaded liposomes, concentrations as low as 500-fold diluted anti-DNP antibody and 0.76 CH50 ml-1 of complement were detected.


Implementation of a thermal biosensor in a process environment: on-line monitoring of penicillin V in production-scale fermentations.

The production of penicillin V was monitored in 0.5 m3 and 160 m3 bioreactors. The thermal biosensor was an enzyme thermistor modified for split-flow analysis. The heat signal generated in the enzyme column was corrected for any nonspecific heat with the use of an identical but inactive reference column. The on-line monitoring was performed in the fermentation pilot plant and in a fermentation plant of Novo Nordisk A/S. Immobilized beta-lactamase was used to monitor three consecutive 0.5 m3 penicillin fermentations. Broth samples were continuously filtered through a tangential flow filtration unit in a sterile external loop. The on-line penicillin V values were 10% higher than those obtained by off-line HPLC analysis. Alternatively a polypropylene filtration probe was inserted into a 160 m3 bioreactor and samples were withdrawn at 0.5 ml/min. The same experiments were repeated with purified and immobilized penicillin V acylase. The on-line penicillin V values obtained with this enzyme correlated very well with those from HPLC analysis. The on-line monitoring was controlled and analysed by a software program written in Labtech Notebook.


Covalent binding of urease on ammonium-selective potentiometric membranes.

As part of the development of disposable urea bioselective probes, the covalent binding of urease on ammonium-selective potentiometric membranes has been assessed. Nonactin/bis(1-butylpentyl)adipate/poly(vinylchloride) (PVC) membranes, directly applied to an internal solid contact (conductive epoxy-graphite composite), has been used as a support for covalent immobilization of urease. Two types of all-solid-state construction process have been assayed: thin layers of cellulose acetate (CA) were coated on the PVC ammonium-selective membranes (type 1) and blends of PVC and CA at various ratios were used as ammonium-selective membrane matrices (type 2). Urease was covalently attached to CA via aldehyde groups. These groups were created on the polysaccharide with sodium periodate to which the enzyme was immobilized through a spacer (hexamethylenediamine). The viability of both types of probe for the determination of ammonium ions was assessed after each step of the activation process. Results indicated that type 2 potentiometric probes are altered after the treatment with sodium periodate. Good results were obtained with type 1 probes. Their dynamic concentration range of response to urea was from 2 x 10(-5) to 0.01 M with a sensibility of 50 mV/decade.


Sulotroban selectively inhibits thromboxane-receptor-mediated responses in the peripheral vascular bed of the cat.

The effects of Sulotroban (BM 13.177, SK&F 95587) were investigated under conditions of controlled blood flow in the hindquarters and mesenteric vascular beds of the cat. Injections of the thromboxane (TX) A2 mimics, U46619 and U44069, caused dose-related increases in perfusion pressure. After administration of SK&F 95587, vasoconstrictor responses to the TXA2 mimics were reduced significantly, and the dose-response curves were shifted to the right in a parallel fashion. Responses to norepinephrine, phenylephrine, tyramine, endothelin-1, angiotensin II, BAY K8644, acetylcholine, sodium nitroprusside, isoproterenol, lemakalim, prostaglandin (PG) E1, and PGF2 alpha, agents which alter vascular resistance by a variety of mechanisms, were not changed by the TXA2 receptor antagonist. However, SK&F 95587 reduced mesenteric vasoconstrictor responses to PGD2. Results of the present study indicate that SK&F 95587 blocks TX-receptor-mediated responses in the hindquarters circulation of the cat in a competitive and selective manner and reduces mesenteric vascular responses to the TXA2 mimics, as well as PGD2. These data suggest that this antagonist would be useful in studies on the role of TXA2 in physiologic and pathophysiologic processes in the systemic vascular bed of the cat.


Role of eicosanoids in rat aortic ring response to agonists and acetylcholine with special reference to the biphasic effects of prostacyclin.

To examine the role of prostanoid release during vascular contraction and endothelium-dependent relaxation, isolated rat thoracic aortic rings were contracted with norepinephrine (NE) or the thromboxane analog U46,619 and then exposed to acetylcholine (ACh). Pretreatment of aortic rings with the cyclooxygenase inhibitor indomethacin decreased (P < 0.05) NE and U46,619-induced contraction. Subsequent ACh-mediated relaxation was also reduced (P < 0.05) in the indomethacin-treated rings. These observations suggest that cyclooxygenase products participate in the rat aortic contractile response to agonists and the relaxation response to ACh. Since prostacyclin has been claimed to contract rat aortic rings, other sets of aortic rings were precontracted to different preloads with NE and then exposed to varying concentrations to prostacyclin (0.02 to 4000 ng/ml). Prostacyclin in modest amounts uniformly decreased aortic ring tension, while greater (> or = 2000 ng/ml) concentrations resulted in a modest contractile response. Prostacyclin per se had minimal contractile effect on quiescent rat aortic rings, but only at unphysiological concentrations. These observations indicate that the primary effect of prostacyclin on rat aortic rings is vasorelaxation, but very high, unphysiological concentrations may result in contraction.


Suggested mechanism for the formation of 15-hydroxyeicosatrienoic acid by rat epidermal microsomes.

We have previously demonstrated that rat epidermal microsomes NADPH-dependently convert 15(S)-hydroperoxy-5,8,11,13-eicosatetraenoic acid (15-HPETE) into 15-hydroxy-5,8,11-eicosatrienoic acid (15-HETrE). The present study examines the mechanism of this reductive conversion. Rat epidermal microsomes were incubated with [1-14C]15-HPETE in the presence and absence of NADPH. Major reaction products were purified by high performance liquid chromatography (HPLC) and analyzed by gas chromatography-mass spectrometry (GC-MS), UV spectroscopy and/or cochromatography with standard products. In the presence of NADPH, 15-HPETE was transformed to 13-hydroxy-14,15-epoxy-5,8,11-eicosatrienoic acid (13-HEpETrE), 15(S)-hydroxy-5,8,11,13-eicosatetraenoic acid (15-HETE), 15-keto-5,8,11-eicosatrienoic acid (15-KETrE) and 15-hydroxy-5,8,11-eicosatrienoic acid (15-HETrE). In the absence of NADPH, the microsomes reacted with 15-HPETE to form 13-HEpETrE, 15-keto-5,8,11,13-eicosatetraenoic acid (15-KETE) and 15-HETE. Furthermore, when supplemented with NADPH, epidermal microsomes converted 15-KETE to 15-KETrE, which was subsequently reduced to 15-HETrE. These data suggest that rat epidermal microsomes are capable of metabolizing 15-HPETE to 15-HETrE via the following reaction steps: conversion of HPETE to KETE, NADPH-dependent double bond saturation in KETE to KETrE and keto-reduction of the latter compound to HETrE.


Thromboxane B2 urinary metabolites in patients undergoing cardiopulmonary bypass.

The urinary excretion of selected markers for renal injury and thromboxane metabolites was studied in 16 patients undergoing cardiopulmonary bypass (CPB). Excretion of both tubular and glomerular markers sharply increased on day 1 after CPB and remained elevated throughout the observation period (five days). Immunoreactive thromboxane B2 (i-TXB2, mainly reflecting 2,3-dinor-TXB2) and immunoreactive 11-keto-thromboxane B2 (i-11-keto-TXB2) were measured by direct enzyme immunoassays. TXB2, 2,3-dinor-TXB2 and 11-keto-TXB2 were also measured in selected samples by GC-MS. Urinary excretion rates of both i-TXB2 and i-11-keto-TXB2 markedly increased on day 1 after surgery and decreased thereafter. Following CPB, excretion rates of 2,3-dinor-TXB2 and TXB2 displayed parallel changes, suggesting that in these patients most urinary TXB2 derives from blood platelets rather than the kidney. Taken together, our observations do not support the hypothesis that acute renal injury observed after CPB is caused by exaggerated thromboxane biosynthesis in the kidney.