Sequence and functional similarity between a yeast ribosomal protein and the Escherichia coli S5 ram protein.

The accurate and efficient translation of proteins is of fundamental importance to both bacteria and higher organisms. Most of our knowledge about the control of translational fidelity comes from studies of Escherichia coli. In particular, ram (ribosomal ambiguity) mutations in structural genes of E. coli ribosomal proteins S4 and S5 have been shown to increase translational error frequencies. We describe the first sequence of a ribosomal protein gene that affects translational ambiguity in a eucaryote. We show that the yeast omnipotent suppressor SUP44 encodes the yeast ribosomal protein S4. The gene exists as a single copy without an intron. The SUP44 protein is 26% identical (54% similar) to the well-characterized E. coli S5 ram protein. SUP44 is also 59% identical (78% similar) to mouse protein LLrep3, whose function was previously unknown (D.L. Heller, K.M. Gianda, and L. Leinwand, Mol. Cell. Biol. 8:2797-2803, 1988). The SUP44 suppressor mutation occurs near a region of the protein that corresponds to the known positions of alterations in E. coli S5 ram mutations. This is the first ribosomal protein whose function and sequence have been shown to be conserved between procaryotes and eucaryotes.

Isolation of omnipotent suppressors in an [eta+] yeast strain.

Omnipotent suppressors decrease translational fidelity and cause misreading of nonsense codons. In the presence of the non-Mendelian factor [eta+], some alleles of previously isolated omnipotent suppressors are lethal. Thus the current search was conducted in an [eta+] strain in an effort to identify new suppressor loci. A new omnipotent suppressor, SUP39, and alleles of sup35, sup45, SUP44 and SUP46 were identified. Efficiencies of the dominant suppressors were dramatically reduced in strains that were cured of non-Mendelian factors by growth on guanidine hydrochloride. Wild-type alleles of SUP44 and SUP46 were cloned and these clones were used to facilitate the genetic analyses. SUP44 was shown to be on chromosome VII linked to cyh2, and SUP46 was clearly identified as distinct from the linked sup45.

Cranial sinus thrombosis and preeclampsia.

Cranial sinus thrombosis (CST) is known to be associated with pregnancy and puerperium. A literature review of patients with CST showed a significant proportion of preeclamptic women. The relationship between nephrotic syndrome and hypercoagulability has been well established. We present a 23-year-old gravida III, para I woman with preeclampsia who developed CST. Proteinuria may have played an important pathogenetic role in this setting.

A non-Mendelian factor, [eta(+)], causes lethality of yeast omnipotent-suppressor strains.

Omnipotent suppressors cause translational ambiguity and have been associated with poor growth and inviability. We now report that a non-Mendelian element, [eta(+)], causes this inviability. In [eta(-)] strains the suppressors are not inviable. The [eta(+)] genetic element segregates to about 70% of the meiotic progeny, although almost all of the spores probably have the [eta(+)] phenotype for the first few divisions. Growth on 5 mM guanidine hydrochloride efficiently causes [eta(+)] strains to become [eta(-)]. The [eta(+)] factor has many similarities with the previously described [psi(+)] factor (Cox 1965, 1971). However, [eta(+)] and [psi(+)] differ in their patterns of inheritance, and by the fact that [psi(+)] affects ochre specific and not omnipotent suppressors, while the converse is true of [eta(+)].

Cushing's syndrome in childhood and adolescence.

OBJECTIVE: To review the diagnosis, management and outcome of Cushing's syndrome in children and adolescents. METHODS: We conducted a retrospective review of nine cases treated between 1976 and 1996 at the Royal Children's Hospital, Melbourne, Australia. RESULTS: Six children with Cushing's disease and three with primary adrenal disease were identified. Mean age at diagnosis in the Cushing's disease patients was 11.3 years and in the children with primary adrenal disease 9.5 years. The most common presenting symptoms were weight gain and delayed growth. Two children had the unusual presenting symptoms of an eating disorder and hemihypertrophy, respectively. Laboratory diagnosis of Cushing's syndrome was established by demonstration of elevated urine free cortisol, loss of normal diurnal variation of serum cortisol, and loss of suppressibility of cortisol secretion by low dose dexamethasone. Investigations used to determine the aetiology of hypercortisolism included serum adrenocorticotropic hormone (ACTH) levels, high dose dexamethasone suppression tests, imaging studies, and inferior petrosal sinus sampling. Four patients with Cushing's disease had successful transphenoidal adenomectomies. Two patients with bilateral primary pigmented nodular adrenocortical dysplasia underwent bilateral adrenalectomies. One child with an adrenal adenoma was treated by left adrenalectomy. CONCLUSIONS: Cushing's syndrome in children and adolescents remains a diagnostic challenge. Successful treatment often requires the use of multiple tests to achieve the correct diagnosis, appropriate surgery and a good long-term outcome.

Exposure to domestic cats: risk factor for Pasteurella multocida peritonitis in liver cirrhosis?

Pasteurella multocida is most commonly associated with acute skin and soft tissue infections following an animal bite or scratch. Peritonitis caused by P. multocida in patients with cirrhosis is rarely reported. We present a case of spontaneous bacterial peritonitis with P. multocida in a patient with cirrhosis, squamous cell cancer of the head and neck, and nontraumatic domestic cat exposure. Nasopharyngeal colonization with P. multocida, with subsequent transient bacteremia and seeding of the peritoneum in immunocompromised (particularly cirrhotic) cat-owners, could play an important pathogenetic role in the development of spontaneous bacterial peritonitis. A review of the literature showed that in nine of 13 patients with cirrhosis and P. multocida peritonitis, exposure to domestic animals was reported. The mortality rate is high in this setting, even with prompt antibiotic treatment. Preventive strategies for immuno-compromised patients should include minimization of animal contact, especially cats, which have a high carriage rate (70-90%) of P. multocida.