Clinical Implications of Complex Pharmacokinetics for Daratumumab Dose Regimen in Patients With Relapsed/Refractory Multiple Myeloma

New therapeutic strategies are urgently needed to improve clinical outcomes in patients with multiple myeloma (MM). Daratumumab is a first-in-class, CD38 human immunoglobulin G1κ monoclonal antibody approved for treatment of relapsed or refractory MM. Identification of an appropriate dose regimen for daratumumab is challenging due to its target-mediated drug disposition, leading to time- and concentration-dependent pharmacokinetics. We describe a thorough evaluation of the recommended dose regimen for daratumumab in patients with relapsed or refractory MM.

Interim analysis of long-term intraduodenal levodopa infusion in advanced Parkinson disease

BACKGROUND

This interim 12-month analysis is a part of an open-label, observational, prospective study on health outcomes and cost impact of levodopa/carbidopa intestinal gel (LCIG, Duodopa) in Parkinson disease (PD). The specific aim was to investigate clinical and health-related quality of life (HRQoL) effects in routine care.

METHODS

Unified PD rating scale (UPDRS) was the primary efficacy measurement. PD QoL questionnaire 39 (PDQ-39) assessed HRQoL. Subjects were assessed at baseline, ≥3 months after surgery, and then every 3 months.

RESULTS

Twenty-seven treatment-naïve subjects when started with LCIG showed a decrease in UPDRS score that was statistically significant throughout the year: UPDRS total score (mean ± SD), baseline = 52.1 ± 16.1, N = 27, month 0 (first visit; at least 3 months after permanent LCIG) = 43.1 ± 16.7, N = 27, P = 0.003; month 12 = 42.5 ± 22.6, n = 25, P = 0.017. PDQ-39 results also showed a tendency for improvement: PDQ-39 (mean ± SD), baseline = 33.6 ± 10.8, N = 27, month 0 = 27.1 ± 11.8, N = 27, P = 0.001; 12 months = 28.8 ± 12.8, n = 23, P = 0.126.

CONCLUSIONS

LCIG provides functional improvement beginning at first visit that is sustained for 12 months.

Electrochemical Tailoring and Optical Investigation of Advanced Refractive Index Profiles in Porous Silicon Layers

Porosity depth profiles with exponential or sinusoidal shape were fabricated electrochemically in crystalline silicon using time-variable current densities and studied employing variable angle spectroscopic ellipsometry. Since volume porosity in porous silicon depends on the current density, it was possible to electrochemically tailor porosity depth profiles, which in a first approximation resembled the time modulation of the applied current. Optical characterization of the samples were realized using multilayer optical models and the Bruggeman effective medium approximation allowing variations of the index of refraction according to the applied current density profiles. The analysis also revealed deviations from desired profiles in terms of in-depth inhomogeneities.

Long-term ECG recordings in hyperthyroid patients before and after antithyroid treatment

Heart rate and heart rhythm were studied in 19 hyperthyroid patients before and after antithyroid treatment inducing a euthyroid state. The mean 24-hour heart rate in patients with sinus rhythm and without drugs influencing heart rate was 100 beats/min before and 80 after antithyroid treatment. The difference was greatest in the sleeping hours. The heart rate, especially in the sleeping hours, correlated significantly with serum triiodothyronine but not with serum thyroxine concentrations.

Feasibility and validity of a computer administered version of SEIQoL-DW

Computer administrered QoL instruments are increasingly used to assess outcomes. Our aim was to assess the feasibility and validity of an electronic version of the SEIQoL-DW. Pharmacy students (n = 40; mean age 25; 92% women) were administrated both the touch screen and the paper-and-pen versions in a cross-over study. The majority of the students (65 %) preferred the computer version, while almost a third (27%) preferred the paper and pen version. There was no overall order effect and the SEOQoL-DW index mean scores differed with 1.2 between the two versions. Those respondents completing the computer version first had higher scores than those completing the computer version second. The ICC comparing the formats was 0.77 (CI: 0.57-0.88) and the limits of agreement method showed that 85% of the observations were within +/- 1-10 units. Most students (82%) judged their QoL as being equivalent to their SEIQoL-DW score. The computer version of the SEIQoL-DW seems to be feasible and acceptable and seems to be valid alternative to the paper and pen version. However, further validation studies in larger patient populations are needed.

Biochemical and immunological properties of cytokines conjugated to dendritic polymers

Here we describe a post-translational modification of SC-63032, a variant of the species restricted, multi-lineage hematopoeitic factor human interleukin-3 (hIL-3). We have made two new dendritic polymer (polyamidoamine or PAMAM dendrimers, generation 5)-SC-63032 bioconjugates. Using two distinct chemistries (one of which is novel to this work), we achieved site-specific conjugation with respect to the amino acid in the proteins ligated to the dendrimers. In both bioconjugates, conjugated cytokine maintains its ability to bind the hIL-3 alpha receptor subunit, but is significantly (about 10-fold) less potent in inducing hIL-3 dependent in vitro cell proliferation than is the free cytokine. In vivo data indicates that conjugation decreases the immunogenicity of the conjugated cytokine modestly. In the absence of pharmacokinetic or biodistribution effects associated with the bioconjugates that increase their potency in vivo (which can only be tested in a higher primate, due to the species restriction of hIL-3 and its derivatives), these immune mitigation effects may be too small to be therapeutically significant. Though unmodified PAMAM dendrimers fail to elicit an antibody response in mice, protein conjugation to dendrimers haptenizes them, and a dendrimer-specific antibody response is produced. In toto, the principal limitation of the dendrimer-cytokine bioconjugates herein is in their reduced receptor affinity and potency in vitro. Were the in vivo potency of the bioconjugates to parallel the in vitro potency of the conjugates reported here, it is likely that particular dendrimer bioconjugates could not justify their higher costs of goods relative to the parent SC-63032 molecule, though retention of SC-63032 biological activities in conjugates suggests that other cytokine-dendrimer bioconjugates may be bioactive. This is good news to the nanotechnology community, in as much as PAMAM dendrimers are among the monodisperse polymeric nanomaterials available, and these results show that they can be used successfully in conjugates to bioactive proteins.

Duodenal levodopa infusion monotherapy vs oral polypharmacy in advanced Parkinson disease

OBJECTIVES

To compare daytime intraduodenal levodopa/carbidopa infusion as monotherapy with individually optimized conventional combination therapies in patients with advanced Parkinson disease (PD) for motor fluctuations and quality of life (QoL).

METHODS

Twenty-four patients with motor fluctuations and dyskinesia were studied in a randomized crossover design to compare individualized conventional treatment and intraduodenal infusion of a levodopa/carbidopa gel for 3 + 3 weeks. Video scoring of motor function was assessed by blinded assessors on a global Treatment Response Scale from -3 to 0 to +3 (from severe "off" to "on" to "on" with severe dyskinesia). Patient self-assessment of motor performance and QoL was done using an electronic diary.

RESULTS

Median percentage of ratings in a functional "on" interval (-1 to +1) was increased from 81 to 100% by infusion therapy (p < 0.01). This improvement was accompanied by a decrease in "off" state (p < 0.01) and no increase in dyskinesia. Median Unified Parkinson's Disease Rating Scale score decreased from 53 to 35 in favor of infusion (p < 0.05). QoL was improved, using the two instruments: Parkinson's Disease Questionnaire-39 and 15D Quality of Life Instrument (p < 0.01). Adverse events were similar for both treatment strategies.

CONCLUSIONS

Continuous intraduodenal infusion of the levodopa/carbidopa enteral gel as monotherapy is safe and clinically superior to a number of individually optimized combinations of conventional oral and subcutaneous medications in patients with motor fluctuations. Intraduodenal infusion of levodopa offers an important alternative in treating patients with advanced Parkinson disease.

Evolutionary consequences of changes in species' geographical distributions driven by Milankovitch climate oscillations

We suggest Milankovitch climate oscillations as a common cause for geographical patterns in species diversity, species' range sizes, polyploidy, and the degree of specialization and dispersability of organisms. Periodical changes in the orbit of the Earth cause climatic changes termed Milankovitch oscillations, leading to large changes in the size and location of species' geographical distributions. We name these recurrent changes "orbitally forced species' range dynamics" (ORD). The magnitude of ORD varies in space and time. ORD decreases gradual speciation (attained by gradual changes over many generations), increases range sizes and the proportions of species formed by polyploidy and other "abrupt" mechanisms, selects against specialization, and favor dispersability. Large ORD produces species prone neither to extinction nor gradual speciation. ORD increases with latitude. This produces latitudinal patterns, among them the gradient in species diversity and species' range sizes (Rapoport's rule). Differential ORD and its evolutionary consequences call for new conservation strategies on the regional to global scale.

Long-Term Responses of River-Margin Vegetation to Water-Level Regulation

The long-term effect of water-level regulation on riparian plant communities was assessed for storage reservoirs and run-of-river impoundments. Soon after the onset of regulation, there were few species and sparse vegetation cover, regardless of whether the new water level intersected former upland or riparian vegetation. In the longer term, an impoverished vegetation was maintained by storage reservoirs, whereas in run-of-river impoundments, some community characteristics deteriorated and others recovered compared to adjacent free-flowing rivers.

Quasi three-dimensional, n-bit optical memory based on the ellipsometric principle: model calculations

Model calculations on the ellipsometric memory are presented. The ellipsometric memory is an n-bit optical memory whose information is extracted by use of the ellipsometric principle. The memory cells of the device consist of thin-film multilayer structures, and the information of each memory cell is contained in the optical properties of the thin films. Several thin-film multilayer structures were examined in order to find out how different choices of layer materials and other system parameters such as layer thicknesses and wavelength affect resolutions and limitations of the ellipsometric memory. Such calculations are also useful for optimizing the readout resolution. It was found that it is possible to use memory cells having up to at least eight layers, which would permit 8-bit words to be stored at each location. It was also found that, in principle, several types of materials can be used as layer materials, and various aspects of different choices of materials are discussed.

Line-shape analysis of ellipsometric spectra on thin organic films

A methodology for the line-shape analysis of ellipsometric spectra on thin (<200-A) organic films is presented. Four different line shapes are employed: Gaussian, Lorentzian, phase-relaxed Lorentzian, and a critical-point line shape. An analysis of analytic data addresses the problem of the modeling of unsymmetric absorption bands. The method is exemplified by an analysis of thin films of phthalocyanine and poly(3-hexylthiophene), and we show that the number and type of resonances in an absorption band can be obtained. The possibility of resolving the cause of a shift in the peak position of an absorption band is also demonstrated. In the case being studied the shift is due to the redistribution of the oscillator strengths between the individual resonances in the band and not to shifts in the energies of the resonances.

Stressful life events and Graves' disease

The role of stressful life events in the onset of Graves' disease (toxic diffuse goitre) is controversial. However, the numerous early clinical reports that supported such an association were not adequately controlled and specificity of the diagnosis could be questioned. Later studies have not shown a causal relation, but these studies were small, did not have proper controls, or epidemiological methods were inappropriate. To assess possible associations between life events, heredity, social support, and Graves' disease, we have done a population-based case-control study in a defined area with about 1 million inhabitants. Over 2 years, 208 (95%) of 219 eligible patients with newly-diagnosed Graves' disease and 372 (80%) of all selected matched controls answered an identical mailed questionnaire about marital status, occupation, drinking and smoking habits, physical activity, familial occurrence of thyroid disease, life events, social support, and personality. Compared with controls, patients claimed to have had more negative life events in the 12 months preceding the diagnosis, and negative life-event scores were also significantly higher (odds ratio 6.3, 95% confidence interval 2.7-14.7, for the category with the highest negative score). Individuals who had relatives with thyroid disease (especially first-degree and second-degree relatives) were more likely to have Graves' disease (3.6, 2.2-5.9). Slightly more patients than controls were divorced (1.8, 1.0-3.3) and reported a less frequent intake of alcohol (0.4, 0.2-0.8). When results were adjusted for possible confounding factors in multivariate analyses, risk estimates were almost unchanged. These findings indicate that negative life events and hereditary factors may be risk factors for Graves' disease.

Effect of short-term indomethacin treatment on the clinical course of acute obstructive cholecystitis

In acute obstructive cholecystitis the increased intraluminal pressure in the gallbladder is reduced by nonsteroid anti-inflammatory drugs which effectively relieve biliary pain. To investigate if such drugs influence the clinical course, a double-blind study was performed in which indomethacin (suppositories 75 mg b.d.) was tested against placebo in 34 patients with acute obstructive cholecystitis. During the 3-day treatment period both the indomethacin and the placebo group improved significantly as regards pyrexia, pain, abdominal tenderness and leukocytosis. The indomethacin group showed significantly greater improvement than the placebo group in temperature, pain and white blood cell count on day 1, and significantly greater reduction of abdominal tenderness on day 2. The serum bilirubin fell significantly during the 3-day period in the indomethacin, but not the placebo group. The hospital stay in cases without early surgery was significantly shorter in the indomethacin group (5.4 vs. 8.5 days). Because of its favourable effect on the clinical course of acute cholecystitis, rectally administered indomethacin is useful for patients awaiting operation or scheduled for later elective surgery.

Is a more active attitude warranted in patients with subclinical thyrotoxicosis?

In 1985 one of the new sensitive thyroid stimulating hormone (TSH) assays was introduced as part of our laboratory routine for thyroid function testing. Consequently, we now routinely identify a small but not insignificant group of patients with 'subclinical thyrotoxicosis', i.e. a low serum TSH in conjunction with a normal serum free T4. We here present the results of a 2-year follow-up investigation, which includes 40 patients with subclinical thyrotoxicosis and 40 euthyroid control patients. The group with subclinical thyrotoxicosis was characterized by a mean age of 65 years and a high prevalence of nodular goitre. Twelve (30%) of the patients but none of the individuals in the control group were treated during the follow-up period because of clinical thyroid disease. Atrial fibrillation was found in 11 (28%) patients compared to four (10%) of the controls. Therapy should be considered more often than previously in patients with nodular goitre and subclinical thyrotoxicosis, particularly in conjunction with atrial fibrillation.

Factors influencing the outcome of thyrostatic drug therapy in Graves' disease

In patients with Graves' disease, thyrostatic drug treatment may induce definitive remission without the need of more aggressive measures such as surgery or radioiodine. Following drug therapy, however, relapses often occur. In the present study, a multivariate analysis of pretreatment variables was performed, in order to identify individuals running a high risk of an unfavourable outcome of thyrostatic drug therapy. We studied 109 consecutive patients with a mean age of 38 years, range 20-70, over a mean follow-up period of 5.3 years after cessation of therapy. The analysis showed that goitre size, age, thyroid hormone levels, HLA-DR 3 haplotype, and TSH receptor antibody levels were of prognostic significance, whereas HLA-B8 haplotype, a lymphocytic infiltrate at fine needle biopsy, thyroglobulin, and microsomal antibodies had no such value. In particular, patients characterized by young age, large goitre and high hormone values were found to be associated with an unfavourable course.

Effects of L-thyroxine and iodide on the development of autoimmune postpartum thyroiditis

In the present study we examined the influence of L-T4 and iodide on autoimmune postpartum thyroiditis. Women at risk of developing the disease were identified in early pregnancy by the presence of moderate or high titers of antibodies against thyroid peroxidase (TPOAb). They were given no treatment (n = 20), 0.1 mg L-T4 daily (n = 18), or 0.15 mg iodide daily (n = 20) for 40 weeks postpartum. Changes in thyroid function were seen in all women, although in nine hormone values remained within the reference ranges of erthymoid individuals. In each group of women, thyrotoxicosis occurred around 2-3 months postpartum, followed by a gradual rise of TPOAb. Subsequently, around 5-7 months postpartum, a hypothyroid phase was observed. TSH elevations (greater than 5 mU/L) occurred in 9 of 18 women in spite of treatment with 0.1 mg L-T4 although elevations were lower than in the other two groups. Among those women who developed abnormal thyroid function, the hormone changes appeared greater in the iodide-treated group than in the control group, suggesting that in certain patients iodide may aggravate rather than ameliorate the disease. All 58 women showed a reduction of TPOAb during pregnancy and a transient rise during the postpartum year. The extent of TPOAb elevations did not differ between the groups. Thus, the administration of L-T4 prevented hypothyroid symptoms, but did not alter the course of the postpartum thyroiditis, which appears not to be accelerated by events of target cell origin.

Postpartum thyroiditis

The special characteristics of postpartum thyroid syndromes are summarized in Table 8. Many of the cases will pass unnoticed, although a higher detection rate is to be expected if postpartum thyroid disease becomes better known among physicians and the general public. Screening in early pregnancy of women with a previous or family history of thyroid disease and in women with other autoimmune disorders (such as diabetes mellitus type 1) may be worthwhile. The initial manifestation of postpartum thyroiditis, often appearing during the first three months postpartum, is a thyrotoxic phase characterized by a low RAIU ('painless thyroiditis' or 'destruction-induced thyrotoxicosis'). Subsequently, a transient hypothyroid phase supervenes. In a small proportion of women hypothyroidism becomes permanent. After a subsequent pregnancy recurrence is the rule. Women who are genetically disposed to Graves' disease may experience thyrotoxicosis with a high RAIU usually appearing later than three months postpartum. As the thyroid function abnormalities are usually mild and transient it is often appropriate to withhold treatment. However, in women with pronounced symptoms treatment should be started. When the postpartum period has passed gradual withdrawal of treatment should be attempted. In women who have experienced postpartum thyroid dysfunction, the risk of developing permanent thyroid disease in later life seems important and therefore long-term follow-up is recommended.

Familial and sporadic medullary thyroid carcinoma: clinical and immunohistological findings

We have studied the clinical and thyroid immunohistological features of 19 patients with sporadic medullary thyroid carcinoma and 16 patients with the hereditary syndrome multiple endocrine neoplasia 2a (MEN 2a). Both groups were identified by family screening using serum calcitonin determinations before and after pentagastrin stimulation. Pheochromocytoma and hyperparathyroidism were associated both with multiple endocrine neoplasia 2a and some cases of sporadic medullary thyroid carcinoma. Hereditary medullary thyroid carcinoma was invariably associated with C-cell hyperplasia, but C-cell hyperplasia was also associated with some sporadic tumours. All tumours were positive for calcitonin and carcinoembryonic antigen (by immunohistological staining) (CEA) and most tumours stained for somatostatin. C-cell hyperplasia also stained for calcitonin, CEA and somatostatin. We conclude that sporadic and familial medullary thyroid carcinoma cannot always be discriminated by clinical or immunohistological methods. Family screening is essential in the diagnosis of hereditary medullary thyroid carcinoma.

The postpartum period constitutes an important risk for the development of clinical Graves' disease in young women

In the present study, 93 consecutive women, 20-40 years of age, referred to our clinic from 1976-85 with Graves' disease, were examined with respect to a possible relation between onset of disease and previous pregnancy. An increased relative risk of 6.5 (3.8-11.0, 95% confidence interval) of developing Graves' disease within one year following delivery was found. After excluding the nulliparous women, almost 2 out of 3 women who developed Graves' disease in the principal child-bearing age of 20-35 years had a postpartum onset, suggesting an important role of immunomodulatory events following delivery for the development of this disease in young women. Future studies will ascertain to which extent the recognition of postpartum Graves' disease has implications on the choice of therapy in this group of women.

Postpartum activation of autoimmunity: transient increase of total IgG levels in normal women and in women with autoimmune thyroiditis

The immunoregulatory mechanisms underlying the transient rebound of autoimmune disease activity in the postpartum period were studied by determining serum immunoglobulins, thyroid microsomal antibodies and some viral (cytomegalovirus, Epstein-Barr, varicellae-zoster and mumps) and bacterial (Yersinia enterocolitica and Salmonella) antibodies in women with autoimmune thyroiditis and in healthy postpartum women. A characteristic increase between 2 and 5 months postpartum followed by a decrease to 10-12 months postpartum was observed not only for thyroid microsomal antibody titres in women with autoimmune thyroiditis but also for serum total IgG and IgG subclass levels (but not IgM, IgA or IgE) in both groups of women. This pattern of transient antibody increase was not detected against viral and bacterial antigens. The characteristic alterations of thyroid microsomal antibody titres in the postpartum period of women with autoimmune thyroiditis thus appear to occur as a consequence of an activation of immunoglobulin-producing B cell clones. This activation seems restricted to the IgG class and to certain B cell clones.

Thyrostatic drugs act through modulation of thyroid cell activity to induce remissions in Graves' disease

Abstract. It has been proposed elsewhere that antithyroid drugs (ATD) bring about remissions in Graves' disease (GD) by directly suppressing the immune system. The decline in thyroid stimulating antibody (TSAb) and other thyroid autoantibodies, and the reduction in intra-thyroidal lymphocytes has been attributed to this effect, which has been considered to be via interference with oxidative reactions within the antigen-presenting cell. However, if ATD exert an immunosuppressive effect, one might expect that this would be a pharmacological action, paralleling the overall pharmacological effect of normalizing thyroid function. Moreover, there is evidence that in Hashimoto's thyroiditis (HT) thyroid autoantibodies do not decline as a result of such treatment. We propose herein that ATD act through modulation of thyroid cell activity, which in turn has an effect on the immune system so as to induce immunological remissions in GD. It has been shown that hyperthyroidism itself has a deleterious effect on generalized suppressor T (Ts) lymphocyte function which is additive to the organ-specific defect in Ts function. Normalization of thyroid function tends to normalize non-specific Ts function; suppression of the thyroid-specific helper T cell (Th) population is thus brought about, in that subset of patients who do not have a severe organ specific Ts defect. This results in a reduction of interferon γ production, as well as reduced Th stimulation of B lymphocytes to produce TSAb. The combined reduction of TSAb and interferon γ will then reduce thyroid antigen and HLA-DR expression, i.e. antigen presentation by the thyroid cell, as well as a further reduction in thyroid hormone production. The latter will further reduce Ts inhibition, reducing Th activity; reduced antigen presentation will also reduce Th activity. This beneficial cycle will then lead to remissions, except in those patients with a more severe organ specific Ts defect.

The secretion of cholecystokinin in the gallstone patient before and after removal of a functioning gallbladder

Cholecystectomy will not always relieve the abdominal symptoms of the patient with gallstones. The functional effects of gallbladder removal in a patient with a patent cystic duct are not known in detail. Studies of the function of the gallbladder and pancreas have suggested feedback mechanisms for the release of cholecystokinin (CCK). A disturbed regulation of CCK release after cholecystectomy might induce pancreaticobiliary and gastrointestinal dysfunctions. In our study the concentrations of CCK in plasma were measured in 17 patients with gallstones. The measurements were taken with gallbladders opacified at cholecystography and with patent cystic ducts at the operation, in the fasting state, and during stimulation before and 17 weeks after the cholecystectomy. The CCK assay used measures sulfated CCK-8, CCK-22, and CCK-33 with equimolar potency but neither nonsulfated CCK nor any gastrins. Emtobil (containing peanut oil and sorbitol) was used for peroral stimulation of the CCK release. The basal concentration of CCK was 4 pmol/L and rose five times during a "test meal." No significant differences were seen in fasting or stimulated concentrations of plasma CCK before and after the cholecystectomy. Thus cholecystectomy in gallstone patients with functioning gallbladders does not seem to influence the regulation of CCK release.

Subacute thyroiditis: activated HLA-DR and interferon-gamma expressing T cytotoxic/suppressor cells in thyroid tissue and peripheral blood

Using a two-colour direct immunofluorescence staining technique, we investigated activated HLA-DR-expressing T helper and T cytotoxic/suppressor cells in peripheral blood of six patients with subacute thyroiditis at referral and at follow-up and in blood from 20 controls. In three of the patients, thyroid fine-needle aspirates were examined as well. At referral, all patients had elevated blood levels of activated T helper and T cytotoxic/suppressor cells 2 (2-4)%, median and range, vs 0 (0-2)%, P less than 0.001 and 12.5 (2-24)%, vs 0 (0-1)% P less than 0.001). At follow-up, the activated proportion of T helper cells had become normal whereas some activated T cytotoxic/suppressor cells remained, 7 (0-8)%. No significant changes in total T cell number were detected when data at referral and at follow-up were compared. In thyroid aspirates, HLA-DR expressing thyrocytes were observed; the total proportion of T cytotoxic/suppressor cells was elevated (70% compared with 35% in blood) and 70% of the T cytotoxic/suppressor cells were HLA-DR+. Furthermore, 55% of the thyroid-infiltrating lymphoid cells were positive for interferon (IFN-gamma+). The finding of activated T cytotoxic/suppressor cells in the blood and thyroid tissue in subacute thyroiditis is consistent with a viral aetiology. Furthermore, intrathyroidal IFN-gamma+ lymphocytes are likely to contribute to expression of major histocompatibility complex (MHC) class II antigens on thyrocytes. No autoantibodies, however, were detected, which suggests that aberrant expression of MHC class II molecules alone is not sufficient to provoke an autoimmune response.

Postpartum thyroid disease

Recent epidemiological studies in Japan and Sweden have disclosed a high prevalence of transient thyroid dysfunction in women following delivery. These changes seem to reflect an immunoregulatory "rebound" following pregnancy-induced immunosuppression. Thyroid microsomal antibody titers characteristically decrease during pregnancy and increase again after delivery to maximum levels around six months postpartum. At this time some microsomal antibody-positive women develop goitrous hypothyroidism. Subsequently, the microsomal antibody titers fall, reaching the early pregnancy values one year postpartum by which time hypothyroidism subsides. The severity of hypothyroidism is closely related to the titer of microsomal antibody, especially the immunoglobulin G1 subclass of microsomal antibody, and partly predictable from the titer in early pregnancy. The HLA-DR4 antigen was observed in 58% of microsomal antibody-positive Swedish women as compared to 33.7% in the general population (relative risk = 2.71). This association was even stronger in microsomal antibody-positive women who developed postpartum hypothyroidism (69%; relative risk = 4.36). Finally, postpartum thyrotoxicosis with a high radioiodine uptake may occur in women with latent Graves' disease. In these cases changes of TSH-receptor-stimulating antibodies analogous to microsomal antibodies seem to occur.

Cholecystokinin secretion after oral Emtobil, a gallbladder-contracting formula

Oral Emtobil, a liquid preparation of sorbitol and peanut oil, has been used in roentgenological practice for several years. Emptying of an opacified gallbladder is seen within 15 min after intake of 100 ml of this solution. The main physiological factor responsible for contraction of the gallbladder is cholecystokinin (CCK). In the present study plasma concentrations of CCK in fasting, healthy subjects were studied in response to oral Emtobil. The radioimmunoassay used measures sulphated CCK-8 and CCK-33 with equimolar potency. Neither non-sulphated CCK nor any gastrins are measured. The average concentration, after an overnight fast in nine healthy subjects without gallstones, was 1.2 pmol/l. A peak concentration was seen within 30 min after 'the test meal' and averaged 8 pmol/l. It is suggested that oral Emtobil contracts the gallbladder by release of CCK. Since Emtobil induces a fast and marked rise in the plasma concentration of CCK, it may be used in test procedures to estimate the secretion of CCK.

Association between thyroid microsomal antibodies of subclass IgG-1 and hypothyroidism in autoimmune postpartum thyroiditis

The potential role of thyroid microsomal (Mic) antibodies in the development of postpartum hypothyroidism was investigated in 34 euthyroid women, whose sera were found to contain Mic antibodies in pregnancy. Additional serum samples were obtained 2. 5 and 10-12 months after delivery and analysed for IgG class and IgG subclass levels of Mic antibodies by ELISA techniques. Characteristically, Mic antibodies decreased from early pregnancy to 2 months postpartum, increased two-fold 5 months postpartum and had returned 10-12 months postpartum to the early pregnancy level. Mic antibodies were predominantly subclass IgG-1 or IgG-4 with only minor contributions from IgG-2 and IgG-3. In each individual the percentage contribution made by each IgG subclass to Mic antibody was essentially similar in early pregnancy and the postpartum period despite changes in total IgG class Mic antibody. During the year following delivery, thyrotoxicosis alone (Graves' disease) developed in 5 women. In the remaining 29 patients the absolute levels of Mic antibodies of IgG-4 subclass were similar 5 months postpartum in women with maximal serum thyrotropin (TSH) greater than 20 mU/1 (mean optical density in ELISA +/- s.d.; 0.84 +/- 0.538; n = 13) and in women with maximal TSH less than 10 mU/l (0.69 +/- 0.457; n = 16). In contrast, significantly higher values were observed for Mic antibody of IgG-1 subclass in patients with TSH greater than 20 mU/l (1.14 +/- 0.440) compared with women with maximal TSH less than 10 mU/l (0.65 +/- 0.289) (P less than 0.001 by t-test for groups). These results imply that the magnitude of Mic antibody levels of subclass IgG-1 but not IgG-4 is associated with the development of postpartum hypothyroidism and possibly with tissue destruction in autoimmune thyroid disease in general.

Thyrotropin-releasing hormone testing during antithyroid drug treatment of Graves' disease as an indicator of remission

In 74 patients with hyperthyroid Graves' disease, TRH tests were undertaken every third month during the course of a standardized antithyroid drug and T4 treatment program. The antithyroid drug dose was reduced gradually and finally withdrawn when persistently normal TSH responses were obtained. In 46 patients (62%), such normal responses occurred and therapy was discontinued after a mean treatment period of 13 months (range, 5-24 months). In the remaining unresponsive 28 patients (38%), therapy was gradually withdrawn after 2 yr of treatment (mean treatment period, 27 months; range, 25-36 months; P = 0.0001 vs. the other group). The mean overall follow-up period after cessation of treatment was 65 months (range, 32-100 months) and did not differ between the TRH-responsive and TRH-unresponsive group. In the TRH-responsive group, 12 relapses (26%) occurred 23 months (range, 6-45 months) after discontinuation of therapy, in contrast to 20 relapses (71%) after 6 months (range, 0-12 months) in the TRH-unresponsive group. The differences in relapse rates and time duration until relapse are highly significant (P = 0.0003 and P = 0.0001, respectively). Small but significant differences in serum T3 and T4 levels were found between the groups throughout the treatment periods, emphasizing the importance of thyroid hormone levels in regulating the pituitary responsiveness to TRH. It is concluded that regular TRH tests during antithyroid drug treatment are useful in deciding the dose and duration of therapy and in predicting the likelihood of remission.

Pharmacokinetic properties and bioavailability of methimazole

The pharmacokinetics of methimazole following therapeutic doses were studied in healthy subjects, in thyrotoxic and hypothyroid patients before and after treatment to euthyroidism, and in patients with renal or hepatic insufficiency, using a highly sensitive gas chromatographic-mass spectrometric assay. Following intravenous administration of 10mg to healthy subjects, methimazole had an initial distribution half-life (t1/2 alpha) of 0.10 to 0.23 hours and an elimination half-life (t1/2 beta) of 4.9 to 5.7 hours. The absolute bioavailability after oral administration of 10mg methimazole in the fasting state was high, with a mean of 93%. The pharmacokinetic profiles showed small interindividual variations, although one of the hypothyroid patients had a rapid elimination half-life, in both the hypothyroid and euthyroid state (2.6 and 2.4 hours, respectively). The elimination rate was not enhanced in the thyrotoxic patients but was slightly prolonged in the hypothyroid patients. There was no influence of renal insufficiency, but a prolonged elimination half-life was observed in patients with hepatic failure, the prolongation being proportional to the degree of impairment. Thus, the pharmacokinetics of methimazole are relatively simple with small interindividual variations. In general, there are no pharmacokinetic reasons to adjust dosage in the treatment of thyrotoxicosis, except in the rare case of concomitant advanced hepatic insufficiency.

Influence of endogenous T3-autoantibodies on thyroid hormone measurements in a woman with transient postpartum thyroiditis

Unreliable estimates of serum total T3 due to the presence of autoantibodies against T3 were observed in a woman who developed thyrotoxicosis followed by transient hypothyroidism after childbirth (postpartum thyroiditis). The T3 autoantibody levels changed during the postpartum period in a similar way to the thyroid microsomal antibodies. The total T3 values were constantly low, whereas the measurement of free T3 by the Amerlex analogue method deviated from the expected only at the time of maximal antibody levels. Thus, evaluation of thyroid function may be complicated by the simultaneous presence of thyroid hormone autoantibodies and transient postpartum thyroiditis.

Thyroxine, methimazole, and thyroid microsomal autoantibody titres in hypothyroid Hashimoto's thyroiditis

Ten hypothyroid patients with Hashimoto's thyroiditis were treated with methimazole 30 mg in addition to thyroxine 0.15 mg daily. Another 10 hypothyroid patients with Hashimoto's thyroiditis were given thyroxine 0.15 mg alone. After 22 weeks of treatment significant decreases in thyroid microsomal autoantibody titres were observed in both groups (p less than 0.01). There was no difference in the mean change in titre between the two groups. When the patients treated with methimazole were subsequently given thyroxine 0.15 mg alone for a further 22 weeks no additional change in titre was observed. The data suggest that thyroxine, by normalising serum thyroid stimulating hormone concentrations, may reduce the autoantigenic properties of the thyrocytes with a subsequent decrease in autoantibody titres.

Influence of the HLA-DR4 antigen and iodine status on the development of autoimmune postpartum thyroiditis

HLA-A, -B, and -DR antigens were determined in all 50 women with a serum thyroid microsomal hemagglutination antibody (MsAb) titer equal to or greater than 1:100 in the first trimester of pregnancy in a population of 733 pregnant women. The DR4 antigen was found in 58.0% of the women compared to 33.7% in control subjects, which corresponds to a relative risk of 2.71 (P less than 0.01 by X2 test). The MsAb-positive women were examined regularly during the year after delivery for the development of thyroid dysfunction. The DR4 antigen frequency was found to be even higher, 69.0% (relative risk = 4.36; P less than 0.001), among the 29 women who developed hypothyroidism in the postpartum period. No other HLA antigen deviations were found among those 15 hypothyroid women in whom an initial thyrotoxic phase occurred before hypothyroidism. The B8, DR3 haplotype was found in 3 of 5 women who developed Graves' thyrotoxicosis alone. Urinary iodine excretion measured in some MsAb-positive women 3 (n = 19) or 6 months (n = 29) postpartum, respectively, was compatible with leakage of thyroid iodine during the initial destruction-induced thyrotoxic phase of postpartum thyroiditis, followed by low iodine excretion during the subsequent hypothyroid phase. We conclude that genes coding for the DR4 antigen may have a regulatory influence on MsAb production, which in turn affects the development of postpartum hypothyroidism. Thyroid iodine content and iodine intake also may have an impact on the severity of the thyrotoxic and the hypothyroid phases of autoimmune postpartum thyroiditis.

Intrathyroidal HLA-DR expression and T lymphocyte phenotypes in Graves' thyrotoxicosis, Hashimoto's thyroiditis and nodular colloid goitre

Thyroid surgical biopsies from 21 individuals were examined by a double immunoenzymatic technique with respect to HLA-DR expression and lymphocytic infiltration. HLA-DR positive thyrocytes were observed in two examined Hashimoto goitres and in nine of 11 specimens from patients with Graves' disease. HLA-DR positive thyrocytes were localized to areas harbouring infiltrating lymphocytes, whereas regions with no lymphocytes only rarely expressed HLA-DR antigens. In two specimens of nodular goitre HLA-DR positive thyrocytes were observed in the vicinity of lymphocytic infiltration. Tissues from another three nodular goitres, from one follicular adenoma and from two normal individuals contained no HLA-DR positive thyrocytes and no or only a few lymphocytes. The lymphocytic infiltrates were dominated by cells with the Leu 3a helper/inducer phenotype irrespective of underlying disease, although most pronounced in Hashimoto's thyroiditis. The results indicate that HLA-DR antigens is expressed on thyrocytes in thyroid disorder. The extent of expression correlated with lymphocytic infiltration, which suggests that the two findings are related and of importance for the development of thyroid autoimmunity.

Free thyroxin index and direct measurements of free thyroxin compared for evaluating postpartum autoimmune thyroid dysfunction

Measurement of free thyroxin (FT4) by a recently introduced commercial assay (Amerlex Free T4 RIA) was compared with the calculated free thyroxin index (FT4I) for serum from 104 postpartum women. Of these, 63 had transient thyroid dysfunction due to autoimmune thyroiditis, six had transient Graves' thyrotoxicosis, and 35 were euthyroid with no signs of autoimmune thyroid disease. The correlation between results for FT4 and the calculated FTI for 95 serum samples from women with no signs of autoimmune thyroiditis (r = 0.941; p = 0.0001) was almost identical to that for 270 serum samples from women with thyroid microsomal autoantibodies characteristic of autoimmune thyroiditis (r = 0.937; p = 0.0001). Furthermore, we observed no difference when the autoimmune group was subdivided according to low or high titers of thyroid microsomal antibodies. In no case did autoantibodies to thyroxin interfere with the FT4 assay. However, one woman had a spuriously low value for FT4I owing to interference by autoantibodies to triiodothyronine with the triiodothyronine resin uptake test. We conclude that the FT4 RIA assay provided diagnostic information in this group of postpartum women equivalent to that of the more elaborate procedure of determining FT4I.

Free thyroxin index and direct measurements of free thyroxin compared for evaluating postpartum autoimmune thyroid dysfunction

Measurement of free thyroxin (FT4) by a recently introduced commercial assay (Amerlex Free T4 RIA) was compared with the calculated free thyroxin index (FT4I) for serum from 104 postpartum women. Of these, 63 had transient thyroid dysfunction due to autoimmune thyroiditis, six had transient Graves' thyrotoxicosis, and 35 were euthyroid with no signs of autoimmune thyroid disease. The correlation between results for FT4 and the calculated FTI for 95 serum samples from women with no signs of autoimmune thyroiditis (r = 0.941; p = 0.0001) was almost identical to that for 270 serum samples from women with thyroid microsomal autoantibodies characteristic of autoimmune thyroiditis (r = 0.937; p = 0.0001). Furthermore, we observed no difference when the autoimmune group was subdivided according to low or high titers of thyroid microsomal antibodies. In no case did autoantibodies to thyroxin interfere with the FT4 assay. However, one woman had a spuriously low value for FT4I owing to interference by autoantibodies to triiodothyronine with the triiodothyronine resin uptake test. We conclude that the FT4 RIA assay provided diagnostic information in this group of postpartum women equivalent to that of the more elaborate procedure of determining FT4I.

Intrathyroidal and circulating lymphocyte subsets in different stages of autoimmune postpartum thyroiditis

Postpartum thyroiditis (PPT) is a reversible form of lymphocytic thyroiditis which has been attributed to an aggravation of preexisting subclinical autoimmune thyroiditis. In this study no differences in circulating lymphocyte subsets were found between 9 thyrotoxic and 18 hypothyroid PPT patients and normal subjects. We obtained sufficient numbers of thyroid-infiltrating lymphocytes for surface marker characterization in 3 women in the thyrotoxic phase and in 10 women in the hypothyroid phase of PPT. Cells were identified by conventional T and B cell markers as well as by monoclonal antibodies (OKT) directed against different T cell subsets in a microscale immunofluorescence assay. In the hypothyroid patients a relative accumulation of B cells (31% vs. 17%; P less than 0.01 by the Wilcoxon signed rank test) was found within the thyroid when compared to peripheral blood. A relative decrease in intrathyroidal supressor-cytotoxic (OKT 8+) T cells (19% vs. 28%; P less than 0.01) resulted in an increased intrathyroidal helper to suppressor-cytotoxic (OKT 4+/OKT 8+) T cell ratio (3.0 vs. 2.0; P less than 0.01). Intrathyroidal lymphocyte subsets in the thyrotoxic patients were comparable to those in the hypothyroid patients. These findings, which are similar to those we previously obtained in patients with chronic Hashimoto's thyroiditis, may indicate that local synthesis of thyroid-directed autoantibodies is of primary importance in all stages of autoimmune thyroiditis.

Autoimmune thyroid dysfunction in the postpartum period

The prevalence of thyroid disease was investigated in 460 Caucasian women after delivery. Thyroid microsomal antibodies (MsAb) were found in 44 (9.6%) of the women. These women appeared to have autoimmune thyroiditis. The changes in MsAb titers followed a predictable pattern with maximal values around 5-7 months postpartum. At this time 20 of these women had transient hypothyroidism and in some this was preceded by a thyrotoxic episode. The extent of postpartum hypothyroidism correlated well with the titers of MsAb in early pregnancy and in the postpartum period. Transient thyrotoxicosis occurred in eight women 5-7 months postpartum. TSH-receptor stimulating antibodies and/or high radioiodine uptake, suggesting Graves' disease, were detected in four of these women. Thus, after delivery, manifestations of autoimmune thyroid disorders, are remarkably common. In patients with autoimmune thyroiditis measurements of MsAb provide a good prognostic marker for the development of transient hypothyroidism.

Comparative bioavailability of carbimazole and methimazole

In this study we investigated the oral bioavailability of therapeutic doses of two antithyroid drugs, methimazole and carbimazole, in seven euthyroid subjects. To increase the statistical power deuterium-labeled methimazole was given orally as an internal standard together with the tested drugs. Using a recently described highly sensitive gas chromatographic-mass spectrometric assay for methimazole we found that intake of 15 mg carbimazole resulted in plasma concentrations of methimazole and pharmacokinetic data comparable to intake of an equimolar amount of methimazole, i. e., 9.2 mg. Maximum concentrations of 163 and 149 ng/ml, respectively, were reached in both instances at 0.9 h after intake of 15 mg carbimazole and 10 mg methimazole. The plasma half-life was 5.7 and 5.4 h, respectively. In contrast to previous suggestions the interindividual differences in pharmacokinetics were small. In conclusion, carbimazole was rapidly and totally bioactivated to methimazole, and the drugs should be regarded as equipotent when compared on a molar basis.

Different aetiologies in post-partum thyroiditis?

During a 4 year period 19 women with post-partum onset of thyroid dysfunction have been seen in our clinic. Five women had high radioiodine uptake thyrotoxicosis (Graves' disease). Twelve women had hypothyroid symptoms starting within 3-6 months of delivery. All of these women had thyroid microsomal and/or cytoplasmic autoantibodies and thyroid lymphocytic infiltration suggesting aggravation of pre-existing subclinical autoimmune thyroiditis (Hashimoto's disease). At follow-up thyroid function gradually improved in all but signs of persistent thyroid hypofunction remained in seven. Thus women developing symptomatic postpartum hypothyroidism should be followed regularly and when thyroxine treatment is commenced in the post-partum period, it has to be continued indefinitely in many cases. Two women presented with transient low radioiodine uptake thyrotoxicosis and a small painless goitre. Thyroid cytology revealed thyroiditis but they had no thyroid autoantibodies. When followed after a succeeding delivery none of these women developed post-partum thyroid dysfunction in contrast to women in the autoimmune group. Probably the aetiology of thyroid dysfunction in these 2 women was different.

Intrathyroidal concentrations of methimazole in patients with Graves' disease

A sensitive gas chromatographic-mass spectrometric method enabled us to study intrathyroidal concentrations of methimazole in 20 euthyroid patients with Graves' disease on treatment with carbimazole and T4. There was no difference between patients receiving a final dose of carbimazole (10 mg), known to be totally bioactivated to methimazole (6.1 mg), 3-6 h before thyroid excision (518 ng/g thyroid tissue +/- 90 SEM) and patients who received the same dose 17-20 h before excision (727 ng/g thyroid tissue +/- 157 SEM), indicating a slow intrathyroidal turnover of the drug. On the other hand, the serum concentrations were much higher in the first group (102 ng/ml +/- 5 SEM vs. 16 ng/ml +/- 3 SEM), reflecting a short plasma half-life of the drug. The intrathyroidal concentrations of methimazole ranged from 230-1895 ng/g among individual glands but were similar in pieces from different parts of a single gland. These methimazole concentrations are lower than the concentrations reported by others to have an immunosuppressive action on lymphocytes in vitro.

Thyroid-infiltrating T lymphocyte subsets in Hashimoto's thyroiditis

In Hashimoto's thyroiditis, the thyroid gland is infiltrated with immunocompetent lymphocytes. In this study we have used the fine needle aspiration technique to obtain thyroid-infiltrating lymphocytes from 11 HT patients for surface marker studies. The cells were characterized using conventional T and B cell markers as well as monoclonal antibodies (OKT) to different T cell subsets in a microscale immunofluorescence assay. We observed a relative decrease in intrathyroidal suppressor phenotype T (OKT 8+) cell numbers compared with peripheral blood (13% vs. 26%; P less than 0.01 by Wilcoxon signed rank test). This resulted in an increased helper to suppressor T (OKT 4+/OKT 8+) cell ratio (4.7 vs. 2.1; P less than 0.01). Within the gland, a significant local accumulation of B cells was also registered (27% vs. 12%; P less than 0.01). As to circulating lymphocyte subsets, no differences were found between 18 Hashimoto's thyroiditis patients and 26 normal subjects. Our results are compatible with a local synthesis of thyroid-directed antibodies and emphasize the importance of studying the local immunity in organ-specific autoimmune disease.

Chromosomal breakage in multiple endocrine adenomatosis (types I and II)

Chromosomal analyses of cultured lymphocytes from nine patients with familial multiple endocrine adenomatosis (MEA) syndrome type I from six families and two patients - father and daughter - with familial MEA syndrome type II showed an increased frequency of chromosomal breakage. The frequency of sister chromatid exchanges was not increased.