A UNIFIED TIME-MARCHING PROCEDURE FOR COMPRESSIBLE INCOMPRESSIBLE FLOWS

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Impaired processing of proopiomelanocortin in corticotroph macroadenomas

The p53 mutations in the reported 243 lung cancers and our 59 cases were analyzed. The common base substitutions found in the lung cancer were G to T transversion (35%), C:G to T:A (26%) and A:T to G:C transitions (11%). Four types of the hot spot, 1) G to T transversion, 2) A to G transition in ApT site, 3) C to T transition in CpG site and 4) mix of the transversion and transition were identified. It is suggested that A to G transition at ApT site in the non-transcribed strand may be a new hot spot in the p53 gene in lung carcinoma. We also show that microscopic selection of cancer cells will facilitate the detection of p53 mutations in adenocarcinomas.     

Differential features of transglottic carcinoma

Actinobacillus actinomycetemcomitans is considered to be an aetiological agent in various forms of periodontitis, with serotype b-specific carbohydrate being the immunodominant antigen of A. actinomycetemcomitans Y4 in high-responder patients. Lipopolysaccharide (LPS) of the organism may also be an important antigen. The purpose of the present study was to clarify the importance of LPS as an antigen of A. actinomycetemcomitans. Twenty patients who had high antibody titres to strain Y4 were selected, and the reactivity of their sera with LPS was determined by ELISA and Western blotting. Two groups of patients were observed: group 1 had high IgG titres only to serotype b strain, whereas group 2 had high IgG titres to serotypes a, b and c strains. The results of adsorption tests showed that anti-A. actinomycetemcomitans Y4 antibody in group 1 patients mostly consisted of antibody reactive with the serotype b-specific carbohydrate, whereas the antibody in group 2 patients mostly consisted of antibody reactive with the LPS of all serotypes. These data show that anti-LPS antibody is present and predominant in anti-A. actinomycetemcomitans Y4 antibody from some high-responder patients, and indicate an important role for LPS as an antigen in the humoral immune response to the organism.     

Functional transplantation of the rat pituitary gland

OBJECTIVE: These studies evaluated the ability of transplanted pituitary cells to restore pituitary function in hypophysectomized rats. METHODS: The pituitary glands of neonatal Lewis rats were rapidly removed, enzymatically dispersed, and stereotactically introduced into the third ventricle of hypophysectomized adult male Lewis rats. Four weeks after implantation, plasma levels of anterior pituitary hormones in implanted animals were compared with those of sham-transplanted control animals. RESULTS: Plasma levels of prolactin, growth hormone, thyroid-stimulating hormone, and beta-endorphin were below the range of detection in 14 sham-operated animals. In implanted animals, restitution of serum prolactin occurred in 100% of the animals tested, with levels of 2.6 +/- 1.0 ng/ml (mean +/- standard error of the mean; normal, 2-4 ng/ml). Growth hormone was assayable in 71% of the animals, with a mean value of 29 +/- 13 ng/ml over all animals (normal, 1-100 ng/ml); thyroid-stimulating hormone was restored in 68%, with mean resting levels of 79 +/- 13 ng/ml (normal, 100-400 ng/ml); luteinizing hormone levels were found in 53%, with mean levels over all animals of 0.2 +/- 0.1 ng/ml (normal, 0.5-1.0 ng/ml); and beta-endorphin was restored in 45% to high resting levels of 163 +/- 31 pg/ml (normal, 20-30 pg/ml). A challenge with hypothalamic releasing factor and a cold stress test were performed on the animals that had received transplants. Positive hormone responses to both of these tests suggested sensitivity of the pituitary grafts to both endogenous and exogenous sources of stimulation. Histological sections of paraformaldehyde-fixed brains from implanted animals clearly demonstrated survival of clusters of grafted pituitary cells. Positive immunohistochemical staining for adrenocorticotropic hormone and thyroid-stimulating hormone was demonstrated in sections of the grafted tissue. CONCLUSION: These data suggest survival of neonatal pituitary transplants in the third ventricle of adult hypophysectomized rats with concomitant restoration of anterior pituitary hormone function.     

Centromere-linkage analysis and consolidation of the zebrafish genetic map

The ease of isolating mutations in zebrafish will contribute to an understanding of a variety of processes common to all vertebrates. To facilitate genetic analysis of such mutations, we have identified DNA polymorphisms closely linked to each of the 25 centromeres of zebrafish, placed centromeres on the linkage map, increased the number of mapped PCR-based markers to 652, and consolidated the number of linkage groups to the number of chromosomes. This work makes possible centromere-linkage analysis, a novel, rapid method to assign mutations to a specific linkage group using half-tetrads.     

Age-dependent effects of muscle vibration and the Jendrassik maneuver on the patellar tendon reflex response

OBJECTIVE: To explore possible effects of aging on the excitability of spinal reflexes. DESIGN: Using a cross-sectional design, the influences of muscle vibration and the Jendrassik maneuver on patellar tendon reflex function were compared between 30 young adults and 15 older adults. SETTING: Motor control research laboratory. SUBJECTS: The young adults were volunteers of college age. The older adults (74.5 +/- 4.14 yr) were volunteers from the local community. All subjects were free of medications and neurological conditions that would affect normal neuromuscular responses. MAIN OUTCOME MEASURES: A force-time curve analysis of the patellar tendon reflex response was used to assess the inhibition and facilitation of spinal reflexes. In the experimental protocol to assess spinal reflex inhibition, 100 Hz vibration was applied to the right quadriceps muscle. In another experimental protocol, spinal reflex facilitation was assessed using the Jendrassik maneuver. To perform the Jendrassik maneuver, subjects were instructed to grasp their hands together and to pull as hard as possible while breathing normally. After a 2-second count, the tendon tap was delivered to the right leg and the subject was instructed to relax. In both experimental protocols, control patellar tendon reflexes were collected. RESULTS: Analysis of variance for reflex peak force revealed a significant 30% reduction in the amount of vibration-induced reflex inhibition with increasing age, and a similar 33% reduction in the amount of Jendrassik maneuver facilitation observed for the older adults as compared with the younger adults. CONCLUSION: These results support the hypothesis that inhibitory and excitatory influences acting on the alpha motoneuron pool are different in young and older adults.     

Fewer bone histomorphometric abnormalities with intermittent than with continuous slow-release sodium fluoride therapy

To help resolve the uncertainty whether sodium fluoride (NaF) therapy should be given intermittently or continuously, we examined iliac crest bone biopsies (before and after treatment) and fragility fracture rates in 35 intermittently treated (group I) and 69 continuously treated (group C) patients; all received calcium. The following statistically significant results were obtained. Reduction in vertebral fracture rate was similar in the two groups. Trabecular thickness and the structurally more important mineralized thickness increased only in group I. Group I also accumulated less excess osteoid (surface, volume). Mean osteoid thickness did not change in either group because of a bimodal distribution of wide seams with osteoblasts and double tetracycline labels, and thin seams without osteoblasts or labels. Osteoid was lamellar. Osteoid in abnormal sites (within bone marrow or bone, or around osteocytes) was found less frequently in group I. Adjusted apposition rate declined and mineralization lag time increased in both groups because of extended unlabelled osteoid seams. Erosion surface increased only in group C. Hook and/or tunnel erosion was seen less frequently in group I; it was closely associated with osteoid in abnormal sites and correlated with osteoid surface. Extended osteoid surface may have forced osteoclasts to hollow out trabeculae, leaving the empty osteoid shell in marrow. Excess osteoid volume and eroded surface and osteoid and erosion in abnormal sites correlated with bone fragility in group C. We conclude that intermittent therapy is to be preferred because it (1) increased mineralized trabecular thickness, (2) did not cause excessive osteoid accumulation and erosion, (3) showed less osteoid and erosion in abnormal sites and (4) led to a similar reduction in the vertebral fracture rate as did continuous treatment. The question of whether intermittency of therapy has some other effect independent of the cumulative dose of fluoride administered cannot be answered by this study.     

Suppressed UDP-galactose: ceramide galactosyltransferase and myelin protein mRNA in twitcher mouse brain

To investigate the role of temporal processing in language lateralization, we monitored asymmetry of cerebral activation in human volunteers using positron emission tomography (PET). Subjects were scanned during passive auditory stimulation with nonverbal sounds containing rapid (40 msec) or extended (200 msec) frequency transitions. Bilateral symmetric activation was observed in the auditory cortex for slow frequency transitions. In contrast, left-biased asymmetry was observed in response to rapid frequency transitions due to reduced response of the right auditory cortex. These results provide direct evidence that auditory processing of rapid acoustic transitions is lateralized in the human brain. Such functional asymmetry in temporal processing is likely to contribute to language lateralization from the lowest levels of cortical processing.