Control of retinal isomerization in bacteriorhodopsin in the high-intensity regime

A learning algorithm was used to manipulate optical pulse shapes and optimize retinal isomerization in bacteriorhodopsin, for excitation levels up to 1.8 × 10¹⁶ photons per square centimeter. Below 1/3 the maximum excitation level, the yield was not sensitive to pulse shape. Above this level the learning algorithm found that a Fourier-transform-limited (TL) pulse maximized the 13-cis population. For this optimal pulse the yield increases linearly with intensity well beyond the saturation of the first excited state. To understand these results we performed systematic searches varying the chirp and energy of the pump pulses while monitoring the isomerization yield. The results are interpreted including the influence of 1-photon and multiphoton transitions. The population dynamics in each intermediate conformation and the final branching ratio between the all-trans and 13-cis isomers are modified by changes in the pulse energy and duration.     

Intravenous immunoglobulin in immune neutropenia

Three patients with immune neutropenia successfully treated with high dose intravenous IgG (IV IgG) are described. In the first case, the neutropenia had not responded to standard steroid therapy; in the second case, very high doses of steroids were required in order to obtain and maintain remission. In the last case, the steroids were contraindicated because of an underlying immunologic disorder. We suggest that these 3 forms of immune neutropenia might be a good indication for IV IgG treatment.     

Childhood IQ measurements in infants with transient congenital hypothyroidism*

OBJECTIVE In view of the fact that, during the first period of life, thyroid hormones are critical for brain development, we investigated whether even transient congenital hypothyroidism could affect the long-term intellectual development of affected infants. DESIGN A case-control study of intellectual development, auxometric parameters and thyroid function performed in late infancy in children with documented transient congenital hypothyroidism or hyperthyrotrophinaemia at birth. PATIENTS Nine children born in an endemic goitre area who had short-term transient congenital hypothyroidism or hyperthyrotrophinaemia after birth (TCH) were studied and compared to nine matched children born in the same area at the same time but having normal thyroid function at birth (N). MEASUREMENTS Global, verbal and performance IQs were evaluated on the Wechsler scale. Height, bone age, total and free thyroid hormones, thyroid volume, thyroglobulin, basal and TRH stimulated TSH were also measured. RESULTS Height and bone age were similar in the two groups. Thyroid function tests were also similar in the two groups except for basal and TRH stimulated serum TSH and serum Tg which were higher in the TCH than in the control group. Global, verbal and performance IQs were systematically lower in the TCH than in the N group. (78.3 ± 11.1 vs 90.9 ± 14.2, P < 0.05; 84.4 ± 15.4 vs 96.2 ± 14.8, P NS; 75.0 ± 8.5 vs 89.2 ± 12.5, P < 0.01 respectively). CONCLUSION Infants born and living in an endemic goitre area, who had biochemical signs of thyroid hypofunction at birth, had a lower intelligence quotient at the age of 7–8 years than matched controls living in the same environmental conditions but with normal thyroid function at birth. The present findings strongly suggest that abnormalities in thyroid function at birth, even when transient, can adversely affect long-term intellectual development.     

The effect of bacterial infection in the worsening of atopic dermatitis: correlations with humoral immunologic patterns

The contribution of secondary infection to severity and tendency to relapse in atopic dermatitis during childhood has been assessed. A total of 57 children aged between 4 months and 14 years were followed for an average of 4.73 months. A secondary infection was diagnosed in 22 (31.4%) of 70 relapses, since the lesions only subsided with antibiotics active on the bacteria isolated from the skin, usually a coagulase-positive Staphylococcus aureus. The eczema was more severe at presentation and hypogammaglobulinemia G more often found in those children who were more susceptible to secondary infections. The hypogammaglobulinemia G was present in 13 out of the 57 patients, but it normalized with age and was not correlated with IgE levels. In the children in whom the relapse or the worsening of the eczema could be attributed to secondary infection because of the positive response to the antibiotic treatment, the lesions had the appearance of pustules or showed more exudation, although in some cases only the worsening of the erythema and itching was observed. A secondary bacterial infection should be considered a likely cause of relapse or worsening of atopic dermatitis. Furthermore it may be that, at least in first year of life, hypogammaglobulinemia G is part of an immunologic impairment of atopic dermatitis which favors the susceptibility to secondary infections.     

Incidental finding of monoclonal gammopathy in blood donors: a follow-up study

Background.The incidental finding of monoclonal immunoglobulin in the sera of healthy blood donors is a relatively frequent event and in such cases the subjects are commonly deferred permanently from donating blood. However, no follow-up studies of these cases have been published so far.Results.Out of 8,197 regular blood donors, monoclonal gammopathy was detected in 104 subjects (1.3%). The median age at detection was 53 years, the median monoclonal protein concentration was 0.2 g/dL and the cumulative follow-up of these cases amounted to 763 person/years. In two cases asymptomatic multiple myeloma was diagnosed within 6 months of detection of the gammopathy and in 14 cases, the monoclonal gammopathy was transient. The remaining 88 cases were classified as having monoclonal gammopathy of undetermined significance (MGUS). Out of these, two events related to monoclonal gammopathy were observed during the follow up: one lymphoma and one light chain deposition nephropathy.Discussion.According to current prognostic staging systems, the majority of blood donors with monoclonal gammopathy were classified as having low-risk MGUS and had a very low incidence of lymphoproliferative diseases. Permanent deferral of blood donors with stable MGUS causes about a 1% loss of potential blood donations and it represents a “precautionary measure” that needs to be substantiated and validated.