Methyldibromoglutaronitrile (Euxyl K400): a new and important sensitizer in the United States?

BACKGROUND

Methyldibromoglutaronitrile (MDGN) is a component of Euxyl K400, a preservative used in many skin care products in Europe. MDGN has been used in skin care products in the United States for the last 5 years. Contact allergy from MDGN has been reported from Europe.

OBJECTIVE

The purpose of this study was to determine the frequency of MDGN as a sensitizer in patients undergoing routine patch testing.

METHODS

We reviewed the results in 163 patients who underwent patch testing during a 4-month period to determine the number who had any reaction to MDGN at two different concentrations (0.2% and 0.5%). Tests were graded with the use of the North American Contact Dermatitis Group criteria (0 to 3+), and readings were performed at 48 and 96 hours (all positive reactions were evaluated at a follow-up visit or by telephone interview).

RESULTS

In the 4-month period, 45 of the 163 patients showed some reaction (+/- to 3+) at one or more readings. Of these, the results for 23 patients were considered to be irritant false-positive reactions; for 3 patients, the results were classified as uncertain; and for 19 patients, the results were classified as allergic. Of these, the results for eight patients were of definite relevance; the results for five patients were of probable relevance, and the results for six patients were of doubtful relevance to the problem condition. Other positive patch tests to a variety of allergens were frequently seen in persons positive to MDGN.

CONCLUSION

MDGN is a sensitizer in skin products and, with the increase of its use, should be considered in the patch test evaluation of patients with persistent dermatitis. Optimum patch test concentrations are yet to be determined.

L-carnitine and acetyl-L-carnitine status during hemodialysis with acetate in humans: a kinetic analysis

The effects of the acetate content of hemodialysis fluids on the relation between L-carnitine (free carnitine, cr FC) and acetyl-L-carnitine (AC) have not previously been examined in detail. The net fluxes of FC, AC, and acetate between intra- and extracellular pools during hemodialysis were calculated using a kinetic model with dialysates containing three concentrations of FC (0, 40, and 80 mumol/L) and either 40 or 3 mmol acetate/L. Radioenzymatic assays of FC and AC were optimized for use with samples taken during hemodialysis. Acetate stimulated a tissue uptake of FC (P < 0.05) that could exceed the rate of FC delivery and was related to the dialysate FC composition (P < 0.02). There were associated changes in tissue AC output. With dialysate containing 40 mmol acetate/L, AC tissue output was directly related to the dialysate FC composition (P < 0.05). The AC tissue output was less with dialysate containing 3 mmol acetate/L (P < 0.05) but the significant increase with the provision of FC in the dialysate was retained (P < 0.05). Hemodialysis may therefore represent an acute period of relative carnitine deficiency when regeneration of free coenzyme A from acetyl coenzyme A consequent to metabolism of acetate is limited.

Plasma non-esterified fatty acid response to dialysate acetate concentration during haemodialysis in humans

We have inhibited the in vitro generation of non-esterified fatty acids in plasma samples taken during haemodialysis by cooling the samples rapidly, centrifuging and freezing within 5 min of sampling and completing the assay on the same day. The relationship of non-esterified fatty acid concentrations during haemodialysis to the acetate concentration of the dialysate and the profile of circulating lipase activities was studied. With this sample-handling protocol we found lower non-esterified fatty acid concentrations than reported in many other studies and the results suggest that, under normal conditions of haemodialysis, the circulating non-esterified fatty acid concentrations and the associated risk of unwanted side-effects may have been previously over-estimated due to artefactual in vitro sample lipolysis. We also showed that, at the end of dialysis, when circulating lipase activities were least, the non-esterified fatty acid concentrations were lower (P < 0.05) with an acetate dialysate containing 37 mmol/l acetate than with a bicarbonate dialysate containing 3 mmol/l acetate.

Distance and pairing effects on the brownDominant heterochromatic element in Drosophila

We examined the behavior of the brownDominant (bwD) heterochromatic insertion moved to different locations relative to centric heterochromatin. Effects were measured as the degree of silencing of a wild-type brown eye pigment gene by bwD across a tandem duplication. A series of X-ray-induced effects were recovered at high frequency. Cis-acting enhancers were obtained by relocation of the duplication closer to autosomal heterochromatin. Enhancers were also recovered on the homologous chromosome when it was similarly rearranged, revealing a novel interhomologue effect whereby interactions occur between genetic elements near opposite ends of a chromosome arm rather than between paired alleles. Cis-acting suppressors were obtained as secondary rearrangements in which the duplication was moved farther away from heterochromatin. Suppression was correlated with loss of cytological association between bwD and the polytene chromocenter. Surprisingly, the distance from bwD to the chromocenter was not correlated with the strength of enhancement or suppression. We propose that bwD fails to coalesce with the chromocenter when its position along the chromosome places it beyond a threshold distance from heterochromatin, and this threshold depends upon the configuration of both the chromosome carrying bwD and its paired homologue.

Immunophenotyping of acute leukemia at King Faisal Specialist Hospital and Research Centre

During a 20 month period, 133 bone marrow samples from an equal number of patients with acute leukemia were immunophenotyped. Patients ranged in age from two to 68 years with a mean of 23 years. Eighty-four (63.2%) were classified as acute lymphocytic leukemia (ALL) with the following immunologic subclassification: common ALL 83.3%, T-cell ALL 11.9%, null-cell ALL 2.4% and 2.4% differentiated B-cell ALL. Twenty-eight cases (21%) were classified as acute myeloid leukemia (AML) and 16 cases (12%) demonstrated biphenotypic features. Concordance with morphology and cytochemistry was observed in 129 cases (97%). Four cases (3%) manifested discrepancy between immunophenotyping, morphology and cytochemistry. We conclude that immunophenotyping by flow cytometry is a useful and reliable method for classification of acute leukemia, especially when interpreted in the light of morphology and cytochemistry.

Immunophenotyping of childhood acute lymphoblastic leukemia in Saudi Arabia: second look

Geographical variations in the incidence of disease are of considerable theoretical and practical importance. It has been claimed that the distribution of acute lymphoblastic leukemia (ALL) phenotypes in Saudi Arabia is different from that recorded in the Western literature. One hundred and twelve (112) patients under 15 years of age, diagnosed as ALL between January 1992 and May 1994 had immunophenotypes performed on their blast cells. Common ALL (cALL) together with pre-B-ALL, formed 86.5% of the total; B-cell 3%, T-cell 6% and null cell 4.5%. These figures are not significantly different from the Western literature. A previous claim from this institution in 1990, that both null and B-cell ALL were significantly increased compared with elsewhere, is not supported by the present figures. Age and sex distribution, and FAB classification, L1 77%, L2 20% and L3 3%, were also of the same order as described elsewhere and, in particular, there was no increase in the frequency of L3 subtype.

Apoliprotein B polymorphism: Application to monitoring early bone marrow transplantation in Saudi population

Seventy-three unrelated Saudi individuals and seven consecutive bone marrow transplant donor-recipient pairs were studied to characterize and determine the frequency of 3' apolipoprotein B alleles by polymerase chain reaction. The samples analyzed were either peripheral blood or bone marrow aspirates. Eleven different alleles were detected. The index of heterozygosity was 0.66. Apolipoprotein B analysis was informative in 57% of the studied donor-recipient pairs. Engraftment was detected as early as day three post-transplantation. The threshold of detection of this allele was up to 0.01x106/ml. Mixed chimerism of the order of 1% could be detected. We concluded that apolipoprotein B is a highly polymorphic allele among the Saudi population and this makes the region a useful marker for monitoring engraftment following allogeneic bone marrow transplantation.

Melatonin shifts human circadian rhythms according to a phase-response curve

A physiological dose of orally administered melatonin shifts circadian rhythms in humans according to a phase-response curve (PRC) that is nearly opposite in phase with the PRCs for light exposure: melatonin delays circadian rhythms when administered in the morning and advances them when administered in the afternoon or early evening. The human melatonin PRC provides critical information for using melatonin to treat circadian phase sleep and mood disorders, as well as maladaptation to shift work and transmeridional air travel. The human melatonin PRC also provides the strongest evidence to date for a function of endogenous melatonin and its suppression by light in augmenting entrainment of circadian rhythms by the light-dark cycle.

Management of segmental defects by the Ilizarov intercalary bone transport method

Seventeen patients with segmental skeletal defects were managed with the Ilizarov intercalary bone transport method, whereby an osseous defect is eliminated by elongating one fragment. On average, the regenerate new bone length measured 5.14 cm, corresponding to the creation of new osseous tissue equaling 13.7% of the bone's original length (range, 4.2%-35%). The average time in fixation was 9.6 months, including 4.8 months to transport the bone fragment throughout the limb. Numerous complications were encountered, most commonly wire-site sepsis and fixator instability. No serous nerve or vessel complications occurred. All but one patient eventually healed, although six patients required bone grafts, five at the target site and one at the level of the regenerate. Most of the difficulties encountered were due to a lack of technical knowledge with the method.

Serological survey for canine cutaneous and visceral leishmaniasis in areas at risk for transmission in Rio de Janeiro where prophylactic measures had been adopted

A serological survey for canine visceral (VL) and American cutaneous leishmaniasis (ACL) has been carried out during 1984-1989, to assess the effects of the prophylactic measures adopted in areas where there was a risk of transmission of the diseases in Rio de Janeiro. A previous serological survey (1982/83) had detected serum positive dogs as well as the human disease in these same areas. A total of 22,828 dogs have been examined in this last survey, 7,807 of which came from Campo Grande (VL and ACL area), 4,110 from Jacarepaguá (ACL area), 4,146 from Realengo, 3,879 from Bangu and 2,886 from Senador Camará, (three VL areas). The analysis of these results showed a notable reduction in the number of serum positive dogs, compared to those of the first survey of 1982/83 as follows: (a) in Campo Grande (VL and ACL) the infection rate of the first survey was 12.7%, against 0.62% of the second; (b) in Jacarepaguá (ACL) it decreased from 8.6% to 1.8% (c) in Bangu, Realengo and Senador Camará (VL) the rate decreased from 4.3% to 0.38%. The results indicate that this decrease was due to the prophylactic measures adopted in those areas.

ICI D7114 a novel selective beta-adrenoceptor agonist selectively stimulates brown fat and increases whole-body oxygen consumption

1. ICI D7114 is a novel, beta-adrenoceptor agonist which stimulates whole body oxygen consumption in conscious rats, cats and dogs and brown adipose tissue (BAT) activity in conscious rats. Treatment of rats with ICI D7114 stimulated oxygen consumption (ED50, 0.04 mg kg-1, p.o.) and BAT mitochondrial guanosine diphosphate (GDP)-binding (ED50, 0.15 mg kg-1, p.o.) with no chronotropic effects on the heart at these doses. 2. Reference beta-adrenoceptor agonists, isoprenaline and clenbuterol, also stimulated oxygen consumption and BAT activity but were less selective because they also produced effects on heart rate at these doses. 3. Treatment of conscious rats with ICI D7114 did not attenuate the chronotropic effects on the heart of a subsequent isoprenaline challenge. 4. Administration of ICI D7114 or of its acid metabolite had no effect in a cat soleus muscle model of tremor or on blood potassium levels in the conscious dog, indicating lack of effects at beta 2-adrenoceptors. 5. The results indicate that ICI D7114 may have activity at atypical beta-adrenoceptors in brown adipose tissue leading to increased whole body oxygen consumption.

Activation and inhibition of bovine carbonic anhydrase III by dianions

We have found that many dianionic species, at millimolar concentrations, significantly activate or inhibit the bovine carbonic anhydrase III-catalyzed hydration of CO2. Dianionic species such as HPO2-4 and SO2-3, with pKb values near 7, are activators, whereas weakly basis species such as SO2-4 act as inhibitors. Both activation and inhibition are partial hyperbolic in nature and do not appear to compete with monoanionic linear inhibitors like N-3. Our kinetic data are consistent with a formal mechanism of action for carbonic anhydrase III that is directly analogous to that of carbonic anhydrase II, in which Lys-64 of carbonic anhydrase III can act as an intramolecular H+ transfer group during CO2 hydration. Our data suggest that dianionic inhibitors depress the rate of H+ transfer during turnover by stabilizing the protonated form of Lys-64. We postulate that dianionic activators enhance the rate of a rate-limiting H+ transfer step in the mechanism, probably by acting directly as H+ acceptors.

The accuracy of predictions about progress of patients on a stroke unit

The aim of the study was to check the accuracy of predictions about the factors which affect the progress, in physical abilities and activities of daily living, of patients admitted to a stroke unit. A series of 60 patients admitted consecutively to a stroke unit were assessed on tests of motor, functional and cognitive abilities at admission. On the basis of these assessments predictions were made about the abilities of the patients at discharge. Patients were assessed for level of motor abilities and activities of daily living at discharge and the accuracy of the predictions checked. Predictions were found to be significantly correlated with outcome but the relationships were not so close as to be useful for the clinical management of individual patients.

Unilateral duplication of the cerebellar hemisphere and internal, middle, and external ear: a clinical case study

This article presents the unique congenital anomaly complex of ipsilateral cerebellar hemisphere duplication and internal, middle, and external ear duplication. Diagnostic techniques included a head CT scan, a three-dimensional head CT scan, and a head MRI. An aberrant notochordal split was proposed as the embryologic mechanism leading to the development of such anomalies.

The effect of surgery and nutritional regimen on plasma lipoproteins and fat metabolites in man

Plasma lipoproteins and fat metabolites were measured before and during the first five post-operative days in patients undergoing elective abdominal surgery of moderate severity. They received nutrition as total parenteral nutrition (TPN) or 4% dextrose saline (D S ) or isotonic aminoacids (IAA). Surgery caused an immediate fall in total and very low density lipoprotein triglyceride and total high density lipoprotein cholesterol but a rise in the high density lipoprotein subfraction 2 cholesterol. The increase in total triglyceride after 5 post-operative days was due principally to changes in triglyceride not carried by very low density lipoprotein and was related to the type of nutrition provided. There was no evidence of impaired intra-vascular lipolysis.

The timing of menarche in juvenile rheumatoid arthritis

A study of the age of menarche in juvenile rheumatoid arthritis (JRA) patients was undertaken to determine what factors affect the timing of menarche. There was a significant difference between the mean age of menarche for the 68 JRA patients and 46 controls (p = 0.015). No clear etiology for this difference was elucidated. Polyarticular-onset JRA patients had the oldest age of menarche, but this finding was of marginal statistical significance (p less than 0.05,pcorr less than 0.25). The multivariate model that included onset type, steroid use, and duration of disease weakly predicted age of menarche in the JRA group. This model suggests that, exclusive of height and weight parameters, duration of disease was the most important predictor of menarche in JRA.