The relationship between serum calcitonin and calcium in the hemodialysis patient

An increase in the serum calcium level is known to stimulate calcitonin secretion, but whether calcitonin contributes to calcium regulation in the dialysis patient is not known. Because we recently observed in the rat that (1) a sigmoidal calcitonin-calcium curve was present, and (2) calcitonin stimulation decreased the calcemic response to parathyroid hormone (PTH), the relationship between serum calcitonin and calcium was studied in six hemodialysis patients. To evaluate both the calcitonin-calcium and PTH-calcium relationships, hemodialysis with a low-calcium dialysate (2 mg/dL) was performed and followed 1 week later by hemodialysis with a high-calcium dialysate (8 mg/dL). The calcitonin-calcium relationship was best represented as a sigmoidal curve that was opposite in direction to the PTH-calcium curve. The range of the calcitonin-calcium curve was less than the PTH-calcium curve; as a percent of maximal, the minimal calcitonin was higher than the minimal PTH, 61% +/- 5% versus 26% +/- 4% (P < 0.001). As opposed to the PTH-calcium curve in which the basal PTH value was intermediate between the minimal and maximal PTH, the basal calcitonin value was close to the minimal calcitonin. Despite a wide range of ionized serum calcium concentrations (3.5 to 5.3 mg/dL), maximal stimulation was greater than maximal inhibition of calcitonin, 60% +/- 13% versus 3% +/- 2% (P = 0.01). Finally, a significant correlation was observed between basal and maximal calcitonin (r = 0.99, P < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of high parathyroid hormone levels on the development of aluminum-induced osteomalacia in the rat

A relative deficiency of parathyroid hormone (PTH) is generally observed in dialysis patients with aluminum-associated osteomalacia or aplastic bone disease. It has been suggested that high PTH levels may protect against the development of aluminum-associated bone disease. Through the use of a previously established model of aluminum-induced osteomalacia in the rat, the protective effect of PTH was evaluated. Aluminum was administered intraperitoneally at doses of 0, 5, 10, and 20 mg during a 2-day period, and rats were sacrificed 5 and 12 days after aluminum administration. PTH (bovine 1-34) was administered via a subcutaneously implanted Alzet pump at 2 U/h starting 4 days before aluminum administration and continuing until sacrifice. As the aluminum dose was increased to 20 mg, the osteoblast surface and the bone formation rate decreased. PTH supplementation increased the osteoblast surface at all doses of aluminum and increased the bone formation rate at 0 and 5 mg of aluminum. However, even with PTH supplementation, osteoblast surface decreased as the aluminum dose increased. In the absence of PTH supplementation, osteoblast surface was markedly reduced when the serum aluminum concentration was greater than 400 micrograms/liter or stainable trabecular aluminum surface exceeded 15%. When the stainable trabecular aluminum surface was greater than 12%, the bone formation rate was zero even during supplemental PTH administration. A significant correlation was observed between serum aluminum and stainable trabecular aluminum surface (r = 0.80 at 5 days and r = 0.86 at 12 days; P less than 0.001). However, after PTH administration, less stainable trabecular aluminum was present for the same serum aluminum concentration. Both with and without PTH, the slope of the correlation between serum aluminum and stainable trabecular aluminum surface was steeper at 5 days after aluminum administration than at 12 days. In conclusion, for an equivalent aluminum exposure, high PTH levels protected against the development of low turnover aluminum bone disease in the rat.

Comparison of clinical significance and allergenic cross-reactivity of storage mites Blomia kulagini and Lepidoglyphus destructor in Sweden and Brazil

Comparison of the clinical significance and allergenic cross-reactivity of Blomia kulagini (B. kulagini) and Lepidoglyphus destructor (L. destructor) was made on sera from Sweden and Brazil using the radio-allergo-sorbent test (RAST) and the RAST inhibition technique. RAST-positive sera were obtained from 53 allergic Swedish farmers and 31 allergic subjects from Brazil who were positive to B. kulagini and/or L. destructor. B. kulagini was shown to be a common cause of sensitization especially in Brazil. There was a fairly high correlation between positive RAST results to L. destructor and B. kulagini based on sera from both Sweden and Brazil. The highest RAST scores were found against L. destructor in Swedish sera and against B. kulagini in Brazilian sera. The RAST inhibition studies showed that the L. destructor extract was able to inhibit the B. kulagini system (a positive RAST to B. kulagini allergen disc) in Swedish but not in Brazilian sera. In contrast, the B. kulagini extract was only able to inhibit the L. destructor system in sera from Brazil and not in sera from Sweden. This study shows that results obtained with RAST inhibition are not entirely dependent on the overall specificity of the IgE antibodies in the patient's sera, since the more subtle specificity of the primarily sensitizing allergen will dominate. Thus, conclusions drawn regarding allergenic cross-reactivity are dependent on the populations tested, and conclusions on the existence or absence of cross-reactivity, e.g. between two species of mites may be contradictory.

Factors influencing the occurrence of late bronchial reactions after allergen challenge

Forty-seven patients with allergic bronchial asthma were challenged with the relevant allergen. Forty-eight per cent of the provocations resulted in a positive immediate reaction followed by a late bronchial response. Late bronchial obstruction was more common among patients with a high than with a low RAST score. Ten patients were challenged with different allergens on two different occasions, but the same type of bronchial response was observed in only six of them. Nine patients with an isolated immediate response were rechallenged with higher allergen doses, the early bronchial response being partially counteracted by terbutaline inhalations in clinically appropriate doses before and during the inhalation of allergen. The treatment alleviated the early reaction in six of the patients. A late reaction occurred in all patients with an immediate response. The non-specific bronchial reactivity to methacholine was assessed in 24 patients before allergen challenge. No relation was found between this reactivity and the observed patterns of reactions to allergen. It was concluded that the occurrence of a late bronchial response probably depends on the dose of allergen administered but is independent of the degree of unspecific bronchial responsiveness to methacholine prior to the challenge.

Immune response to Blomia kulagini and Dermatophagoides pteronyssinus in Sweden and Brazil

The immune responses to the non-pyroglyphid mite Blomia kulagini and the pyroglyphid mite Dermatophagoides pteronyssinus were compared in 440 Swedish farmers and 34 allergic subjects from Brazil using the radioallergosorbent test (RAST). Both B. kulagini and D. pteronyssinus were shown to be a common cause of sensitization, particularly in Brazil. The highest RAST scores were found against D. pteronyssinus in sera from both countries. Allergenic cross-reactivity between the two mites was studied by the RAST inhibition technique. Both B. kulagini and D. pteronyssinus possess their own unique allergens as well as allergens in common. Thus, besides mites belonging to the Dermatophagoides genus, other pyroglyphid and non-pyroglyphid mites in different countries should be taken into consideration before starting hyposensitization treatments.

Hydroxylapatite cranioplasty directly over dura

Seven patients who had noticeable defects of their frontal bone were reconstructed with dense hydroxylapatite (HA) particles with or without autogenous bone placed directly over the dura. The results indicate that HA is well tolerated over dura; no meningitis occurred with follow-up of one to 3 1/2 years. The clinical response was excellent and complications were minor, generally related to particle control and settling.

Early and late allergic bronchial reactions: physiological characteristics

Twenty-four patients with asthma of suspected allergic origin were subjected to a total of twenty-five bronchial provocations with the relevant allergen. Eighteen of them reacted with bronchial obstruction: eleven with an isolated early reaction, five with a dual reaction and two with only a late reaction. Extensive lung function tests were performed. The patterns of early and late reactions were qualitatively very similar regarding variables of pulmonary physiological function, but there were quantitative differences. Patients with dual reactions showed significantly greater changes in FEV1, RV and TGV during the early response than those with isolated early reactions. Maximum mid-expiratory flow rates with the patients breathing air and a mixture of He and O2 were measured before and 6 hr after the challenges. Four of five patients with both an immediate and a late response showed a decrease in the response to helium during the latter phase, suggesting increasing involvement of the small airways. An increase in the slope of the alveolar plateau (phase III) was observed in four of the five patients with dual responses and all five had increased CC%. It was concluded that the changes in pulmonary function occurring during the dual responses were widespread, involving the airways generally and resembling those in the clinically more severe asthma. Usually, individuals with dual reactions showed stronger reactions. In two cases, however, a late reaction was obtained without any preceding early reaction.

Increased bronchial hypersensitivity after early and late bronchial reactions provoked by allergen inhalation

The non-specific bronchial reactivity following bronchial allergen challenge was studied in 40 patients with allergic bronchial asthma, particularly in subjects without definite late reactions 6 h after the provocations (reduction in peak expiratory flow or forced expiratory volume in 1 s of less than 15% of the control value at this time). Among a group of 21 patients submitted to bronchial provocation tests, 13 carried out maximal exercise tests 6 and 1 week after the allergen challenge. In another group of 19 patients, the bronchial hyperreactivity to methacholine was assessed before and 6 h and 1 week after challenge. Two patients with a dual response (early & late) reacted with bronchial obstruction to the exercise. Exercise tests performed after 1 week did not provoke asthma in any patient. In the methacholine group a marked increase in responsiveness to methacholine 6 h after the provocation was observed in those patients with a dual response who were tested and in those with equivocal late reactions and even in three patients with an isolated immediate reaction. The increases responsiveness was still present in many patients 1 week after challenge. The airway caliber did not influence the degree of responsiveness to methacholine. Nor did the degree of responsiveness have any influence on the patterns of reactions observed after allergen exposure. It was concluded that in some individuals exposure to the relevant allergen predisposes them to exercise-inducible bronchial obstruction. Further, it was confirmed that non-specific bronchial reactivity can be increased not only in patients with late responses - both definite and equivocal--but also in some patients with immediate reactions alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Late allergic bronchial reactions and the effect of allergen provocation on the complement system

Forty-nine bronchial provocations were performed with different allergens in allergic asthmatic patients. Immediate bronchial reactions occurred in 33 instances, and late reactions occurred in nine instances. The material was divided into three groups according to patients with no reactions, patients with early reactions alone, and patients with late reactions. Titers of whole complement and factors C2 and C3 were determined hemolytically, and the serum protein contents of factors C3, C4, and C1q were measured immunochemically. Decreases in complement and complement components were observed on a number of occasions after bronchial challenge. When the groups were compared with respect to mean change in complement titers, the three groups were indistinguishable. No change was noted in the ratio between the complement contents in venous and arterial blood as a result of provocation, nor did the specific hemolytic activity of factor C3 change. No C3 split products could be traced. It is likely that there will be a higher proportion of patients with C2 consumption among those with late bronchial reactions. No special feature could be assigned to these individuals, however. It is concluded that no major complement activation is regularly found in allergic asthmatic patients as a result of exposure to allergens. However, groups of patients in whom such activation takes place might exist.

Respiratory symptoms in ispaghula-allergic nurses after oral challenge with ispaghula suspension

Ispaghula powder, which is used as a component in bulk laxatives, is known to induce allergic reactions when inhaled by occupationally exposed persons. We have tested whether nurses sensitized by inhalation could get allergic symptoms when challenged by eating ispaghula. Of six nurses tested, all developed symptoms from the airways, one of them even pronounced ones requiring treatment. In all cases the dose required to produce symptoms was below the single dose of ispaghula used as a laxative.

Dust exposure challenge test as a measure of potential allergenicity and occupational disease risk in handling of Ispaghula products

It is known that workers in the pharmaceutical industry, and nurses, can become sensitized and develop allergic respiratory symptoms by handling bulk laxatives containing Ispaghula powder. Fifteen individuals allergic to Ispaghula were challenged with a commercially available Ispaghula product and three other products manufactured in a way to make them less dusty. The results show that the use of products with smaller amounts of airborne particles results in a lower incidence of symptoms and thus probably reduces the potential occupational risk of sensitization to the Ispaghula allergen.

Another smoking hazard: raised serum IgE concentration and increased risk of occupational allergy

Individual smoking histories of a general population sample and of two groups of workers exposed to occupational allergens were related to serum IgE concentrations and results of radioallergosorbent and prick tests in the workers. The geometric mean IgE concentration was higher in smokers than in non-smokers. The distribution of serum IgE values in the two groups showed an apparent difference, with a bimodal appearance in the smokers. Evidence of sensitisation against occupational allergens was more common in workers who smoked. The adjuvant effect of smoking on IgE antibody production might be due to damage to airways mucosa and supports the mucosal theory of atopy.

Occupational allergy in nurses to a bulk laxative

Finely ground psyllium (Plantago ovata) seeds, so-called ispaghula powder is used in bulk laxatives. During the dispensing of these medicines some dust is generated. Allergic symptoms from exposure to this dust was reported by two nurses, one of whom was wroking in a department where exposure to the powder could be considered high. Nineteen other subjects working in the same department were investigated with regard to allergy to ispaghula powder. An extract from ispaghula powder was made and used in RAST and skin tests. Exposure tests with ispaghula powder mixed with crushed rusks were made in symptomatic subjects. Eight out of the 20 investigated subjects from this department reported symptoms which could possibly have been elicited by ispaghula powder. Evidence of sensitization was found in five of them. The use of less dusty (granulated) forms of ispaghula laxatives might diminish the risk of sensitization.