Differential roles of the Leloir pathway enzymes and metabolites in defining galactose sensitivity in yeast

The metabolism of galactose via enzymes of the Leloir pathway: galactokinase, galactose-1-P uridylyltransferase, and UDP galactose-4'-epimerase, is a process that has been conserved from Escherichia coli through humans. Impairment of this pathway in patients results in the disease galactosemia. Despite decades of study, the underlying pathophysiology in galactosemia remains unknown. Here we have defined the functional and metabolic implications of impaired galactose metabolism in yeast, by asking two questions: (1) What is the impact of loss of each of the three Leloir enzymes on the ability of cells to metabolize galactose, and on their sensitivity to galactose, and (2) what is the relationship between gal-1P and galactose-sensitivity in yeast? Our results demonstrate that only transferase-null cells are able to deplete their medium of galactose; deletion of kinase or epimerase halts this process. In contrast, only kinase-null cultures grow well in glycerol/ethanol medium despite the addition of galactose; both transferase and epimerase-null yeast arrest growth under these conditions. Indeed, epimerase-null yeast arrest growth at galactose concentrations 10-fold lower than do their transferase-null counterparts. Secondary deletion of kinase relieves growth arrest in both strains. Finally, rather than a continuous relationship between gal-1P and growth arrest, we observed a threshold level of gal-1P (approximately 10 nmol/mg cell DM) above which both transferase-null and epimerase-null cultures could not grow. These results both confirm and significantly extend prior knowledge of galactose metabolism in yeast, and set the stage for future studies into the mediators and mechanism of Leloir-impaired galactose sensitivity in eukaryotes.     

Endogenous animal models of intracranial aneurysm development: a review

Neurosurgical Review - The pathogenesis and natural history of intracranial aneurysm (IA) remains poorly understood. To this end, animal models with induced cerebral vessel lesions mimicking human...     

The Accuracy of Incident Vertebral Fracture Detection in Children Using Targeted Case-Finding Approaches

Vertebral fractures are clinically important sequelae of a wide array of pediatric diseases. In this study, we examined the accuracy of case-finding strategies for detecting incident vertebral fractures (IVF) over 2 years in glucocorticoid-treated children (n = 343) with leukemia, rheumatic disorders, or nephrotic syndrome. Two clinical situations were addressed: the prevalent vertebral fracture (PVF) scenario (when baseline PVF status was known), which assessed the utility of PVF and low lumbar spine bone mineral density (LS BMD; Z-score <−1.4), and the non-PVF scenario (when PVF status was unknown), which evaluated low LS BMD and back pain. LS BMD was measured by dual-energy X-ray absorptiometry, vertebral fractures were quantified on spine radiographs using the modified Genant semiquantitative method, and back pain was assessed by patient report. Forty-four patients (12.8%) had IVF. In the PVF scenario, both low LS BMD and PVF were significant predictors of IVF. Using PVF to determine which patients should have radiographs, 11% would undergo radiography (95% confidence interval [CI] 8–15) with 46% of IVF (95% CI 30–61) detected. Sensitivity would be higher with a strategy of PVF or low LS BMD at baseline (73%; 95% CI 57–85) but would require radiographs in 37% of children (95% CI 32–42). In the non-PVF scenario, the strategy of low LS BMD and back pain produced the highest specificity of any non-PVF model at 87% (95% CI 83–91), the greatest overall accuracy at 82% (95% CI 78–86), and the lowest radiography rate at 17% (95% CI 14–22). Low LS BMD or back pain in the non-PVF scenario produced the highest sensitivity at 82% (95% CI 67–92), but required radiographs in 65% (95% CI 60–70). These results provide guidance for targeting spine radiography in children at risk for IVF. © 2021 American Society for Bone and Mineral Research (ASBMR).     

The relationships among height,penile length,and foot size

To determine whether "folk myths" regarding the relationships of penile size to body height and foot size have any basis in fact, 63 normally virilized men were studied. Height and stretched penile length were measured; shoe size was recorded and converted to foot length. Penile length was found to be statistically related to both body height and foot length, but with weak correlation coefficients. Height and foot size would not serve as practical estimators of penis length.     

Short Communication: Interaction of aflatoxin B2 with rat liver DNA and histones in vivo

The interaction of aflatoxin B₂ (AFB₂) in vivo with rat livernuclear macromolecules was examined in an attempt to correlatethis binding with biological potency. The incorporation of [³H]AFB₂residues into rat liver his tones and DNA was determined 2,24 and 48 h following administration of a single i.p. dose of1 mg (³H)AFB₂/kg body weight. At each time point, hist one H1and the total histone fraction contained 5–30-fold more[³H]AFB₂ moieties than did DNA on a weight basis. Analyticalreversed-phase h.p.l.c. of the acid hydrolysis products resultingfrom AFB² binding to DNA revealed that 85% of the radioactivityco-chromatographed with the major aflatoxin B₁-DNA adduct, 2,3-dinydro-2-(N⁷-guanyl)-3-hydroxyaftatoxinB₁. These studies revealed an apparent correlation between AFB₂derived binding to DNA in vivo in rats and its potency as atoxin and carcinogen in this species.     

Direct gamete uterine transfer in patients with tubal absence or occlusion

Purpose: Our aim was to examine the potential of the uterine cavity to affect fertilization and early embryo development. Design: A prospective IRB-approved protocol for patients fulfilling study eligibility criteria was used. Methods: Patients studied included those with primary or secondary infertility, aged less than 38 years, with no history of severe male-factor infertility, and with hysterosalpingogram-and laparoscopic-confirmed bilateral proximal tubal occlusion. Superovulation induction was accomplished with a combination of GnRH agonist and menotropins, with serum hormonal and sonographic monitoring. Within 24 hr prior to, and again at the time of, ovulatory hCG administration, progesterone (P4) was given. Sonographic-guided transvaginal retrieval was performed 35 hr after hCG. Between four and six oocytes were returned to the uterine cavity, admixed with sperm, immediately following retrieval. Luteal support consisted of daily P4 administration. Results: Of the 20 patients recruited for the study, all completed the retrieval and transfer procedure. A total of four clinical pregnancies was achieved, with one early first-trimester loss, one late first-trimester loss (Trisomy 14), and two healthy term infants delivered. IVF of surplus oocytes demonstrated a 82.5% fertilization rate and 66.7% cleavage following cryopreservation. Conclusions: Human fertilization can be achieved through direct uterine transfer of gametes. Furthermore, administration of P4 prior to the ovulatory dose of hCG is compatible with in vitro or in vivo fertilization and implantation.     

Oral and written story composition skills of children with language impairment.

In this study 538 children composed 1 oral and 1 written fictional story in both 2nd and 4th grades. Each child represented 1 of 4 diagnostic groups: typical language (TL), specific language impairment (SLI), nonspecific language impairment (NLI), or low nonverbal IQ (LNIQ). The stories of the TL group had more different words, more grammatical complexity, fewer errors, and more overall quality than either language-impaired group at either grade. Stories of the SLI and LNIQ groups were consistently stronger than were those of the NLI group. Kindergarten children with language impairment (LI) whose standardized test performance suggested normalization by 2nd grade also appeared to have recovered in storytelling abilities at that point. By 4th grade, however, these children's stories were less like the children with TL and more like those of children with persistent LI than they had been in 2nd grade. Oral stories were better than written stories in both grades, although the greatest gains from 2nd to 4th grade were generally made on written stories. Girls told stronger stories than did boys at both grades, regardless of group placement. It is concluded that story composition tasks are educationally relevant and should play a significant role in the evaluation of children with developmental LI.     

Prepulse inhibition deficits in GAD65 knockout mice and the effect of antipsychotic treatment.

Recent postmortem studies in humans suggest that defects in GABAergic neurotransmission might contribute to the neuropathology associated with schizophrenia. Disturbances in GABAergic systems may also contribute to the sensorimotor gating deficits classically observed in schizophrenic patients, including deficits in prepulse inhibition (PPI). To explore the relationship, the current study examined the integrity of PPI and startle habituation in knockout (KO) mice that lack the GABA synthesizing enzyme glutamic acid decarboxylase 65 (GAD 65). GAD65 KO mice displayed normal baseline and habituated startle responses, which did not differ from GAD65 wild-type (WT) or heterozygous (HET) mice. However, GAD65 KO mice showed robust deficits in PPI which were reversed by the atypical antipsychotic agent clozapine. These results lend support to the view that abnormalities in GABAergic systems might contribute to the basic pathophysiological mechanisms in schizophrenia.