Hexokinase I Messenger RNA in the Rat Central Nervous System

Hexokinase I (ATP: -hexose 6-phosphotransferase, EC 2.7.1.1) is the first enzyme required in the metabolism of glucose in the central nervous system and plays a major role in regulation of the cerebral glycolytic rate. The distribution of hexokinase I mRNA was examined throughout the central nervous system of the rat by use of oligonucleotide probes and in situ hybridization histochemistry. In the rhinencephalon, strong hexokinase I mRNA labeling was demonstrated in the glomerular, mitral, internal granular, and internal plexiform layers, whereas the olfactory nerve, external plexiform, and subependymal layers and ependyma were devoid of labeling. Within the telencephalon, strong labeling was present in all layers (with the exception of the molecular layer) of the cerebral cortex, in the septum, in CA1-4 and dentate gyrus of the hippocampus, and in several amygdaloid nuclei. There was only weak labeling in the nucleus accumbens and caudate putamen. In the diencephalon, there was in general a strong labeling in the epithalamus, in several thalamic nuclei, including the anteriodorsal, anterioventral, anteriomedial, reticular, paravetricular, intermediodorsal, anteriomedial, interanteriomedial, rhomboid, reuniens, and parafascicular thalamic nuclei. Several hypothalamic regions, including the subfornical organ, the medial preoptic area, the suprachiasmatic, supraoptic, paraventricular, dorsomedial, ventromedial nuclei, and the zona incerta, were strongly labeled. In the mesencephalon, there was particularly strong labeling in the pars compacta and reticulata of the substantia nigra, central gray, and red nucleus, in the Darkschewitsch nucleus, and in the medial accessory oculomotor nucleus. In the rhombencephalon, there was strong hybridization in all raphe nuclei, pontine, tegmental, lateral parabrachial, olivary nuclei, and several cranial motor nuclei. All neurons of the locus ceruleus were heavily labeled. Very strong labeling was present in Purkinje and granular cells of the cerebellar cortex. Neurons of the medulla oblongata area postrema, nucleus tractus solitarius, reticular nucleus, nucleus cuneatus and several motor nuclei were strongly labeled. In the spinal cord, labeled cells were present in all laminae, and also neurons of the dorsal root ganglion were heavily labeled. Hexokinase I mRNA was also demonstrated in the epithelium lining the choroid plexus. In the E15 fetus, very strong labeling was seen in the liver, heart, and trigeminal ganglion, with less intense labeling in the brain and other tissues having more moderate labeling. Administration of 2% saline as drinking water resulted in a marked increase in hexokinase I mRNA in the magnocellular neurons of the supraoptic and paraventricular nuclei. In summary, the results show extensive neuronal distribution of hexokinase I mRNA with regional differences in the expression pattern.     

Chromosomal integrity maintained in five human embryonic stem cell lines after prolonged in vitro culture

There have been recent reports of human embryonic stem cell (hESC) lines developing chromosomal aberrations after long-term culture, indicating an unstable genomic status due to the in vitro milieu. This raises concern, since it would limit their use in therapeutics. In this study the chromosomal status of five well-characterized hESC lines, SA002, SA002.5, AS034.1.1, SA121 and SA461, was monitored during long-term in vitro culture. The criteria of defined hESCs were met by all of the five hESC lines (four diploid and one trisomic for chromosome 13). The genomes were screened for chromosomal aberrations and rearrangements using comparative genomic hybridization (CGH), interphase fluorescence in situ hybridization (FISH) and traditional karyotyping on several occasions while in culture. The genomic integrity was shown to be maintained after repeated freeze-thaw procedures and continuous culture in vitro for up to 22 months (148 passages). We discuss the most common de novo chromosomal aberrations reported in hESCs, as well as their possible origin.     

Selective Attention Effects on the Reflex Blink

Past work has shown that facilitation of reflex blinking accompanies cardiac deceleration when the attention of subjects is directed to a reflex-eliciting stimulus. The present studies showed that when warning stimuli directed attention instead to weak (tactile) stimuli presented simultaneously with reflex-eliciting (acoustic) stimuli, cardiac deceleration was still present but reflex magnitude was unchanged or inhibited. However, latency to reflex onset remained facilitated, i.e., latency and magnitude changes were discordant. The findings were interpreted as evidence for two independent processes: a process capable of selectively enhancing or attenuating sensory input and a non-selective process presumably facilitating motor pathways.     

Rat Jejunal Permeability and Metabolism of μ-Selective Tetrapeptides in Gastrointestinal Fluids from Humans and Rats

Purpose. To study intestinal transport and metabolism of three new -selective tetrapeptide enkephalin analogues, LEF537, LEF553 and TAPP These peptides are stabilized against enzymatic hydrolysis by having a D-aminoacid in position 2 and a blocked COOH-terminal. Methods. We used a single-pass perfusion technique to study the transport of the peptides in rat jejunum. To reduce luminal and/or brush-border metabolism during the perfusion we used protease inhibitors (Pefabloc^® SC, bestatin and thiorphan). The rate of metabolism was studied by incubations in rat jejunal homogenate, rat jejunal fluid and human gastric and jejunal fluid with and without these inhibitors. Results. The jejunal permeabilities (P_eff) of the peptides were 0.43–0.78 10^–4 cm/s without inhibitors and 0.09–0.45 10^–4 cm/s in presence of the inhibitors. All three peptides were rather rapidly degraded by enzymes in rat jejunal homogenate with half-lives of between 11.9 ± 0.5 and 31.7 ± 1.5 min. The addition of inhibitors to the homogenate prolonged the half-lives substantially for LEF553 (167 ± 35 min) and TAPP (147 ± 2 min), but only slightly for LEF537 (16.4 ± 0.5 min). LEF553 and TAPP were both hydrolyzed in rat and human jejunal fluid, while LEF537 was metabolized less in these fluids. When LEF553 and TAPP were incubated with intestinal fluid in the presence of inhibitors, metabolism was almost completely inhibited. There was no metabolism for any of the peptides in human gastric juice. Conclusions. The replacement of the terminal free carboxylic group with an amide group did not increase the stability of the peptides in jejunal tissue enough to allow successful oral drug delivery.     

Clinical classification of Swedish snuff dippers'' lesions supported by histology

From a total material of 184 Swedish users of loose packed moist snuff and 68 users of portion-bag packed moist snuff, cases were selected from subgroups based on a four-point clinical grading scale. The selected material for the study comprised 70 cases (ten from each clinical grade group, no Degree 4 lesion was found among portion-bag users). Features recognized in biopsies from these cases together with findings in previous studies correlated well with the use of a four-point scale for the grading of clinical changes, especially in the context of discriminating lesions for which special efforts should be undertaken to make the patient stop or change the snuff dipping habit and for selecting patients in whom regular clinical follow-up including a biopsy should be carried out. In this article is also discussed the labeling of the clinical oral mucosal changes seen at the site where a quid of snuff is regularly placed. The conceptual use of "snuff dippers' lesions" is recommended instead of e.g. snuff-induced leukoplakia.     

Effectiveness of low-dose contrimoxazole prophylaxis against Pneumocystis carinii pneumonia after renal and/or pancreas transplantation

We retrospectively examined the effectiveness of prophylaxis with cotrimoxazole in preventing Pneumocystis carnii pneumonia in recipients of kidney and combined kidney-pancreas transplants between 1985 and 1989. Cotrimoxazole prophylaxis (480 mg daily or 300 mg/m²), when used, was started within 2 months after transplantation and usually continued until 6 months after surgery. Eight (3.7%) of the 214 patients who were not given prophylaxis were infected with Pneumocystis carinii, and there were 4 fatalities (50% mortality). There were no cases among the 161 patients given prophylaxis (P 0.03). No serious adverse effects were noted in the prophylaxis group. It is concluded that prophylaxis against Pneumocystis carinii infection is well tolerated and should be given as soon as possible to all organ transplant recipients for at least 6 months.     

Knowledge of reproduction in teenagers and young adults in Sweden.

OBJECTIVE: To investigate the knowledge of reproductive physiology and anatomy among adolescents and young adults in Sweden, and to evaluate the education obtained on these issues. METHODS: Two hundred and nine study specific questionnaires were distributed, of which 206 were answered by students in primary school, upper secondary school and at first year of university. A total knowledge score based on 21 out of the 35 questions in the questionnaire was calculated. As only 44 of the 206 respondents answered all the questions a revised score was also calculated, in which partial dropouts were interpreted as wrong answers. RESULTS: The mean of the total knowledge score was 28.7 out of 54 among the 44 respondents answering all questions, and the revised knowledge score was 24.0. The level of knowledge tended to be higher in older age groups, among women, as well as among respondents who had visited a Youth clinic. The time of ovulation was known by 21.4% of men compared to 63.4% of women. Almost 50% of the students knew one mechanism whereby oral contraceptives act to protect against pregnancy. Of the respondents, 77.2% knew of Chlamydia trachomatis but the knowledge of other STIs, like condyloma, was poorer (16.5%). Reasons for infertility were relatively well known among the respondents. Of the respondents, 57.5% stated that they had not received enough information on reproductive issues. CONCLUSIONS: The students have not achieved sufficient knowledge concerning sexual and reproductive matters that they, according to the national curriculum, should have attained by the end of the 9th grade. An improvement of the quality of the education, adapted to the students' age and pre-existing knowledge, and a review of the contents of the education is therefore needed.