A spectrometric study of the Co(2+)-activated ribulose-1,5-bisphosphate carboxylase reaction during turnover and at different pH.

EPR as well as optical absorption studies of the Co(2+)-activated ribulose-1,5-bisphosphate carboxylase/oxygenase under turnover conditions show that the formation of the two detectable intermediates are pH dependent. The amount of one of them, which earlier has been proposed to be a metal coordinated endiol of ribulose-1,5-bisphosphate (Brändén et al. (1987) Biochim. Biophys. Acta 916, 298-303), increased with increasing pH. Distinct optical absorption bands could be assigned to this intermediate and a pH profile could be made. It is therefore proposed that a base with a pKa value of about 8 is responsible for the enzyme-catalysed abstraction of a proton from ribulose-1,5-bisphosphate in order to form the metal coordinated endiol of ribulose-1,5-bisphosphate.

Studies of the Co2+-activated ribulose-1,5-bisphosphate carboxylase/oxygenase by the use of spectrophotometry.

Transient optical absorption bands are formed upon addition of ribulose-1,5-bisphosphate to the Co2+-activated ribulose-1,5-bisphosphate carboxylase/oxygenase from spinach and parsley. In the visible region, the prominent absorption band during steady state has a maximum at 610 nm. Stopped-flow technique was used to study the increase in absorbance at this wavelength, and two distinct phases in the progress curve for the approach to steady-state absorbance were observed. The rates for these two phases, respectively, were similar to those found earlier for the two enzyme-Co2+-bound intermediates using EPR technique (Brändén et al. (1987) Biochim. Biophys. Acta 916, 298-303). It is therefore proposed that most of the transient optical absorption originates from an enzyme-Co2+-coordinated ribulose-1,5-bisphosphate molecule and an enzyme-Co2+-coordinated enediolate anion of it, where bound ribulose-1,5-bisphosphate appears first. Furthermore, the most rapid phase in the progress curve is a first-order reaction, independent of the ribulose-1,5-bisphosphate concentration. This indicates that the formation of enzyme-Co2+-coordinated ribulose-1,5-bisphosphate is preceeded by another reaction in which ribulose-1,5-bisphosphate binds to the enzyme, probably without metal coordination.

Intermediates formed by the Co2+-activated ribulose-1,5-bisphosphate carboxylase/oxygenase from spinach studied by electron paramagnetic resonance spectroscopy.

Two enzyme-metal-bound intermediates formed by the Co2+-activated ribulose-1,5-bisphosphate carboxylase/oxygenase (EC 4.1.1.39) have been studied by electron paramagnetic resonance (EPR) spectroscopy. Their rates of approach to a stationary state are different and their relative amounts at steady state are dependent on the concentration of ribulose 1,5-bisphosphate. It is therefore proposed that enzyme-metal-coordinated ribulose 1,5-bisphosphate and an enzyme-metal-coordinated enediolate anion of it, where bound ribulose 1,5-bisphosphate appears first, constitute the two EPR-detectable intermediates, respectively.

Expression of DWnt6, DWnt10, and DFz4 during Drosophila development.

Members of the Wnt gene family encode secreted proteins that signal through the Frizzled family of receptors to function in many aspects of development. In this study, we have analyzed the expression of two Wnt genes and one Frizzled family member that were recently identified through the Drosophila genome sequencing project. We show that DWnt6 is only weakly expressed in developing embryos, with transcripts faintly detected in the gut. By late third instar however, this gene is expressed in a pattern that is identical to that of wingless (wg) in the imaginal discs. DWnt10 is expressed in the embryonic mesoderm, central nervous system and gut, whereas its expression is below the levels of our detection in third instar imaginal discs. We find that DFz4 is also expressed in a dynamic pattern in the mesoderm, gut, and central nervous system.

Displacement of left kidney suggesting adrenal tumor.

Several infants with a left suprarenal "cold spot" shown on technetium scintiphotos were also found to have inferior displacement of the left kidney on the urogram. Surgical exploration was considered on the basis of possible adrenal tumor; however, the highly suspicious "lesion" disappeared after gastric deflation, and it was recreated after gastric distention. Review of infant urograms has shown that gastric distention is a common cause of a "normal" low-lying left kidney, in clear distinction to the adult in whom a displaced left kidney frequently shows a pathologic condition.

Duodenal hematoma. Critical analysis of recent treatment technics.

Analysis of the fifty-six cases of duodenal hematoma reported since 1966 shows a significant rise in incidence, with uncertainty regarding the most appropriate approaches to therapy. The diagnosis can generally be made by recognizing the "coil spring" sign on upper gastrointestinal series. Thirty-four per cent of the patients reviewed were treated successfully with conservative management. Sixty-two per cent were treated surgically. Fifty-one per cent of the surgical patients were treated by simple evacuation of the hematoma, and 12 per cent of these required reoperation for recurrent obstruction. Forty per cent of the surgical patients were treated by evacuation and gastrojejunostomy, and 21 per cent of these required reoperation for marginal ulceration. A previously unreported case is presented and a new surgical approach utilizing gastroduodenostomy is described, which is believed to offer potentially less risk of subsequent marginal ulceration or recurrent duodenal obstruction.

Infants in play groups: time related changes in behavior toward mothers, peers, and toys.

Twenty-one 13-month-old infants, nine male and 12 female, were assigned to one of seven playgroups convening for 15 consecutive weekdays . Present at each 20-minute play session were three same-sexed peers with their mothers and an assortment of toys. There were systematic fluctuations in infants' attention to mother, peers, and toys. There findings suggest that a mother may serve different functions at different points in time: (a) as a secure base in initial sessions, (b) as a refueling stop when the infant grew tired, and (c) as an attractive alternative when the infant became bored with toys and peers. Within-day analyses revealed that activity level and toy exploration linearly decreased over time, while intentional contact with mother significantly increased. Social interaction with peers correlated negatively with interaction with mother over the course of the study. Sex differences over time were found to be significant: boys on day one were more interactive with both peers and toys but this level declined thereafter, while girls on day one spent more time in close proximity to mother and later, on subsequent days, increased their peer and toy play.

Selection and migration in two distinct phenotypes of Littorina saxatilis in Sweden.

Two distinct phenotypes of the marine snail L. saxatilis, the 'E morph' from exposed rocky habitats, and the 'S morph' from nearby sheltered boulder shores, were released and survivors recaptured at 3-monthly intervals. Survival rate of E morphs was significantly higher than that of S morphs in the exposed habitat, whilst the revers was true for the sheltered site. When released in an environment intermediate between the exposed and sheltered habitats, both morphs survived equally well. However, snails native of this area, 'I morphs', survived better than both E and S morphs here. Recapture rates were highest in spring. Large snails of both phenotypes were selected against in the exposed habitat. In the sheltered environment, small E morph snails survived better than large ones, and both sizes of S morphs survived equally well. E morph individuals transplanted to a different exposed locality than their native one, had lower survival rates compared to native individuals. This effect was not found among transplanted S morph snails.Distances migrated since time of release were on average greater in the sheltered than in the exposed habitat, and within the range of 1-4 m per 3 months, for both habitats. In a laboratory experiment, both morphs showed a shelter-seeking behaviour, most pronounced in the E morph.It is proposed that the strong selection differences between the morphs within the two different habitats, the absence of a planktonic larval stage, and a restricted migration among juvenile and adult snails, maintain a genetic polymorphism within the species, responsibel for considerable parts of the large phenotypic differences observed between the two morphs E and S.

Non-invasive localization of urinary tract infection.

New methods to localize the source of bacteriuria were evaluated in monkeys with experimental urinary tract infection. A high level of diagnostic accuracy was obtained with the combined study of antibody-coated urinary bacteria by immunofluorescence, 131I hippuran scintiphotos in the hydropenic state and 67gallium citrate scintiphotos. Unique patterns were found, which differentiate cystitis, ureteritis, pyelonephritis and renal or perinephric abscesses.

Experimental pyelonephritis. V. Functional characteristics of pyelonephritis.

Changes in renal and ureteral function were studied in monkeys with experimental pyelonephritis, and correlated with the findings of 131I Hippuran scintiphotos. During the acute phase, delayed excretion of radionuclide was found to be a combined result of prolonged intrarenal as well as ureteral transit times. During the chronic phase, scintiphoto studies revealed decreased renal uptake of radionuclide suggesting decreased renal blood flow. Subsequent individual renal function studies confirmed the decrease in renal function and provided data that strongly support the "intact nephron hypothesis" in chronic pyelonephritis.

Multiple endocrine adenomatosis: in support of the common origin theories.

Herein we give clinical support to the theory of a common origin of multiple endocrine adenomatosis. Accurate clinical evaluation of a patient suspected to have endocrine neoplasia requires the search for a much wider range of potential endocrine tumors. Such an approach is now made possible by the radioimmunoassay. Chromosome patterns and histocompatibility antigens are reviewed in a family with the disease.

Imaging normal and abnormal brain development: new perspectives for child psychiatry.

OBJECTIVE: The availability of non-invasive brain imaging permits the study of normal and abnormal brain development in childhood and adolescence. This paper summarizes current knowledge of brain abnormalities of two conditions, attention deficit hyperactivity disorder (ADHD) and childhood onset schizophrenia (COS), and illustrates how such findings are bringing clinical and preclinical perspectives closer together. METHOD: A selected review is presented of the pattern and temporal characteristics of anatomic brain magnetic resonance imaging (MRI) studies in ADHD and COS. These results are discussed in terms of candidate mechanisms suggested by studies in developmental neuroscience. RESULTS: There are consistent, diagnostically specific patterns of brain abnormality for ADHD and COS. Attention deficit hyperactivity disorder is characterized by a slightly smaller (4%) total brain volume (both white and grey matter), less-consistent abnormalities of the basal ganglia and a striking (15%) decrease in posterior inferior cerebellar vermal volume. These changes do not progress with age. In contrast, patients with COS have smaller brain volume due to a 10% decrease in cortical grey volume. Moreover, in COS there is a progressive loss of regional grey volume particularly in frontal and temporal regions during adolescence. CONCLUSIONS: In ADHD, the developmental pattern suggests an early non-progressive 'lesion' involving neurotrophic factors controlling overall brain growth and selected dopamine circuits. In contrast, in COS, which shows progressive grey matter loss, various candidate processes influencing later synaptic and dendritic pruning are suggested by human post-mortem and developmental animal studies.

Noninvasive localization of urinary tract infection: clinical investigations and experience.

Previously we evaluated new methods to localize the source of bacteriuria in monkeys with experimental urinary tract infection. A high level of diagnostic accuracy was obtained with studies of antibody coating of urinary bacteria by immunofluorescence, 131iodine hippuran quantitative scintillation camera studies with the patient in the hydropenic state and 67gallium citrate scintiphotos. We identified unique patterns that differentiated cystitis, ureteritis, pyelonephritis and renal or perinephric abscess. Herein we review our clinical experience with these combined techniques in 40 patients and correlate the degree of accuracy of these studies with that of standard radiographic examinations. In 20 patients diagnostic studies also were compared to the findings of split ureteral urine cultures or bacteriologic culture of renal tissue obtained from surgical specimens or autopsy. The use of the quantitative scintillation camera studies done with the patient in a state of controlled hydropenia increased clearly the level of diagnostic sensitivity in demonstrating the source of a urinary tract infection compared to urine culture and excretory urography alone. In patients with an abnormal 131iodine hippuran study the performance of 67gallium renal imaging on the same day usually provided information that allowed specific localization of the source and extent of an infection. Both studies must be performed with a high degree of resolution over the renal areas and then must be interpreted carefully to ensure accuracy. Study of antibody coating of urinary bacteria was helpful in suggesting the presence or absence of upper urinary tract disease but was less sensitive and accurate than the combined radionuclide studies.

Digital rectal examination, serum prostate specific antigen, and prostatic ultrasound: how effective is this diagnostic triad?

Ninety-nine of 105 consecutive men who underwent transrectal prostatic ultrasound (TRUS) at Highland Park Hospital had the results correlated with digital rectal examination (DRE), serum prostate specific antigen (PSA), and biopsy results. Ninety-six cases had evaluable ultrasound studies. Thirty-two of the 99 who underwent biopsy had primary carcinoma of the prostate. Prostate volume, predicted PSA, a ratio of observed/predicted PSA, and Gleason score were examined. There was no correlation between age and prostate volume, volume and the presence of carcinoma, or PSA and Gleason score. Thirty-one point six percent of the abnormal DREs, 36.6% of the abnormal TRUSs, and 40.6% of the elevated PSAs occurred in men with prostatic carcinoma (PCa). If PSA was normal (less than or equal to 4.0 ng/ml) and either DRE or TRUS was abnormal, then the risk of carcinoma was 2.9%. If PSA was elevated, regardless of the other two tests, the risk of finding PCa was at least 38%. If all three tests were abnormal, the risk of carcinoma was 38% in our series and 68% in a meta-analysis. Many men with PSA values between 4 and 10 ng/ml have benign biopsies. However, close future follow-up with consideration of repeat biopsy should be strongly considered.