Phosphorylation of endogenous proteins of cilia from Paramecium tetraurelia in vitro.

Several endogenous substrate proteins of cilia from axenically grown Paramecium tetraurelia were phosphorylated in vitro by inherent protein kinases (PKs). Labeling was stimulated by cAMP and to a lesser extent by cGMP. ATP breakdown was most rapid in cilia and subciliary fractions. Using multiple substrate additions during incubations it was shown that phosphorylation was almost completed within 30 s. Very little dephosphorylation by phosphoprotein phosphatases occurred during 5 min of incubation. Proteins of molecular weight of 103 000 and 46 000 were shown to be particularly associated with axonemal structures of the cilia. No distinct differences in phosphorylation patterns were apparent in ciliary membrane vesicles of low and high buoyant density, which exhibit differential enzyme patterns. cAMP receptor proteins were identified by use of the photoaffinity label 8-azido-[32P]cAMP. Receptor proteins with apparent molecular weights of 43 000, 39 000, 37 000, 31 000 and 30 000 were probably related to the regulatory subunits of cAMP-dependent protein kinases as evidenced by inhibition of incorporation of the photoaffinity label by low concentrations of cAMP. Tagging of a protein of 85 000 molecular weight was specifically inhibited by cGMP, thus in all likelihood it corresponded to a cGMP-dependent protein kinase. Corresponding autophosphorylated protein bands were observed with gamma-[32P]ATP. A functional role for protein phosphorylation in cilia of Paramecium remains to be established.

Tuberculin and anergy skin testing of patients receiving long-term hemodialysis.

STUDY OBJECTIVES: Immunocompromised patients with chronic renal failure requiring hemodialysis (HD) are at increased risk of developing tuberculosis (TB). Routine TB screening of this population is recommended. This study examined the frequency of TB reactions and anergy in HD patients in a community with a high prevalence of TB. DESIGN: Outpatients in a hospital-based HD center were screened with tuberculin, Candida, and mumps antigen. RESULTS: Forty percent of patients were anergic and 19% were tuberculin reactors. No demographic factors correlated with either test results. CONCLUSIONS: There was a high rate of TB infection and anergy in this HD center. Despite the high rate of anergy, tuberculin testing remains a useful test in this population. Anergic patients require further clinical evaluation for TB. Other HD programs should tuberculin and anergy test their patients to determine prevalence in their populations.

Safety of the American Heart Association Step 1 Diet in childhood.

Can we totally answer the question of the safety of the American Heart Association Step 1 Diet in children over the age of 2 years? Available evidence certainly points to this diet as being safe and not harmful to growing children. A major concern of cholesterol-lowering diets is the misapplication of nutritional guidelines. However, this concern is not exclusive to cardiovascular related nutrition. Therefore, we feel confident that this diet can be implemented in the general population without any adverse effects on growth and development in North American children. It seems prudent to continually monitor children in different settings as is being currently evaluated in certain ongoing studies such as the Dietary Intervention Study in Children (DISC). The DISC program is monitoring children's growth, development, and nutritional status to insure no long-term adverse effects of Step 1 Diets. The focus of future strategies and investigations should be to identify effective methods for the dissemination of accurate nutritional information. Proper education via school programs, the various forms of media, and instructions from educated allied health professionals may all play a major role. It is essential that a variety of strategies be used to provide information and guidance to the general population and to families with children who have high blood cholesterol levels.

Schiff-base deprotonation is mandatory for light-dependent rhodopsin phosphorylation.

The absorption of light by rhodopsin leads to the formation of an activated intermediate (R*) capable of catalysing the exchange of GTP for GDP in a retinal guanine-nucleotide-binding regulatory protein (transducin). The ability of R* to function as a catalyst is terminated by the rhodopsin kinase. The 10 nonactive-site lysine residues of rhodopsin can be reductively dimethylated to form permethylated rhodopsin (PMRh). This derivative is phosphorylated to the same extent as rhodopsin after photolysis. The monomethylation of the active-site lysine residue of PMRh yields active-site-methylated rhodopsin (AMRh). It had previously been shown, by using AMRh, that the formation of R* and its spectroscopic signature metarhodopsin II requires the photochemically induced deprotonation of the active-site Schiff base [Longstaff, Calhoon & Rando (1986) Proc. Natl. Acad. Sci. U.S.A. 83, 4209-4213]. Here it is demonstrated that active-site Schiff-base deprotonation is also mandatory in the formation of the form of photolyzed rhodopsin that is susceptible to phosphorylation by rhodopsin kinase. In terms of the spectroscopically defined rhodopsin intermediates, this means that only metarhodopsin II and possibly metarhodopsin III are the actual substrates for rhodopsin kinase.

Hospital care of tuberculosis patients referred for directly observed therapy in New York City: identifying factors in prolonged stays.

Individuals hospitalized and treated for tuberculosis (TB) who were then enrolled into TB directly observed therapy at four study hospitals in New York City (NYC) were identified. Review of hospital medical records determined whether the hospitalizations were warranted and whether lengths of stay were prolonged. Most hospitalizations were appropriate but over 70 percent of cases analyzed had prolonged stays. Of these, almost half were to document bacteriologic response to anti-TB treatment. Some were prolonged due to misunderstanding of state recommendations. Focused educational efforts could significantly reduce lengths of stay and save up to $9.7 million annually in NYC hospitalization costs.

Family history fails to identify many children with severe hypercholesterolemia.

Optimal strategies for identifying children with hypercholesterolemia have not been established. Several groups have advocated that testing of serum cholesterol levels be limited to those children who have family histories of hyperlipidemia or premature coronary heart disease. We studied the ability of comprehensive family histories to identify children with hyperlipidemia in a group of 114 children (mean age, 8 +/- 4 years) who were referred for treatment of hypercholesterolemia. A positive family history was defined according to guidelines of the American Academy of Pediatrics. The mean fasting total cholesterol in the children was 5.74 +/- 1.42 mmol/L (222 mg/dL). Family history was negative for hypercholesterolemia or premature coronary heart disease in 22 (22%) of 100 children with total cholesterol levels greater than the 75th percentile for their ages, in 13 (18.3%) of 71 children with total cholesterol levels greater than the 95th percentile for their ages, and in four (11.8%) of 34 children with presumed heterozygous familial hypercholesterolemia. Of the 78 children who had both hypercholesterolemia and positive family histories, hyperlipidemia was reported in 72 families, whereas premature heart disease was reported in only 27. We conclude that in a population of children referred because of known hypercholesterolemia, a detailed family history not only fails to identify many children with mild hypercholesterolemia, but also fails to identify a significant proportion of children with markedly elevated cholesterol levels. Additionally, in families of children with hypercholesterolemia, a history of hyperlipidemia is more common than a history of premature heart disease.