A DNA binding factor (UBF) interacts with a positive regulatory element in the promoters of genes expressed during meiosis and vegetative growth in yeast

We have studied the bipartite regulatory element UASH/URS1 in the promoter of HOP1, whose product is required for synapsis and correct pairing of homologous chromosomes during the first meiotic division. HOP1 is transcriptionally repressed by the URS1 motif during vegetative growth and induced during meiotic prophase by the UASH motif in cooperation with the bifunctional URS1 site, which is required for full induction of HOP1. While URS1 is bound in vitro by the Buf and Ume6 repressor proteins, we demonstrate for the first time by electrophoretic mobility shift assays and interference footprinting that the UASH site interacts in vitro with a novel factor called UBF (UASH binding factor) which is present in haploid and diploid cycling, as well as sporulating cells. Point mutations in the HOP1 UASH motif abolish UBF-dependent DNA binding activity in vitro and meiotic HOP1 gene expression in vivo. Furthermore, we show that UBF binds in vitro to UASH-like sequences in the promoter regions of several meiosis-specific and non-specific genes and propose that UBF mediates gene expression through its interaction with the UASH motif in both cycling and sporulating cells.

The serotonin 5-HT4 receptor. 2. Structure-activity studies of the indole carbazimidamide class of agonists

A number of substituted indole carbazimidamides were prepared and evaluated as 5-HT4 receptor agonists by using the isolated field-stimulated guinea pig ileum preparation. Their selectivity for the 5-HT4 receptor was established by examining their affinity for other 5-HT receptors using radioligand-binding techniques. Several selective and highly potent full as well as partial agonists emerged from this study. For example, 1b,d were found to be the most potent, full 5-HT4 receptor agonist described so far (EC50 = 0.5 and 0.8 nM, respectively), being 6 and 4 times more potent than serotonin itself. On the other hand, 5b and 1h appeared as partial 5-HT4 receptor agonists in the nonstimulated guinea pig ileum preparation with potencies, evaluated against serotonin action, respectively similar (5b, Ki = 12 nM) to and 300-fold higher (1h, Ki = 0.04 nM) than serotonin.

The serotonin 5-HT4 receptor. 1. Design of a new class of agonists and receptor map of the agonist recognition site

The design and synthesis of a new class of potent and selective 5-HT4 receptor agonists containing an indole nucleus linked to a carbazimidamide are presented. A conformational study of the 5-HT4 receptor agonists serotonin and zacopride led to the identification of an initial pharmacophore and to the definition of a three-dimensional map of the 5-HT4 agonist recognition site. 1, a representative member of our new class of 5-HT4 receptor agonists, incorporates all reference structural features and matched perfectly with these models. 1 is a highly potent, full agonist at 5-HT4 receptors present in the isolated electrically stimulated guinea pig ileum preparation, with a pD2 value of 8.8, displaying selectivity (ranging from 40- to over 10,000-fold) versus other members of the serotonin receptor family.

Unchanged renal haemodynamics following high dose ascorbic acid administration in normoalbuminuric IDDM patients

The object of the study was to test whether high dose ascorbic acid (AA) could normalize glomerular hyperfiltration in insulin-dependent diabetes mellitus (IDDM) patients. A prospective, double-blind, randomized, placebo (tartaric acid, TA) controlled study design was used, with parallel treatment lasting 4 weeks. Measurements were made before and after treatment, on 24 normoalbuminuric, normotensive male IDDM patients, who were randomized to ascorbic acid (n = 12, age 35 years (18-39), diabetes duration 12 years (2-12), BP 128/82 mmHg (SD 14/6)), or to placebo (TA) (n = 12, age 30 years (19-36), diabetes duration 8 years (2-17), BP 119/75 mmHg (SD 9/7). The intervention consisted of 6 enterosoluble tablets of 500 mg AA or 213 mg TA, twice a day, being daily doses of 6 g AA or 2.55 g TA. No significant differences in any of the parameters measured were seen, when comparing results following AA or placebo treatment. The glomerular filtration rate (GFR, clearance of 125I-iothalamate) was unchanged while effective renal plasma flow (ERPF, clearance of 131I-hippuran) tended to decline in both groups. The GFRs before and after treatment in the AA-treated group were 141 (SD 15) and 134 (SD 12) ml min-1 1.73 m-2; NS (2p = 0.09). In the TA-treated group they were 142 (SD 19) and 137 (SD 16) ml min-1 1.73 m-2; NS (2p = 0.20). The ERPFs in the AA group were 584 (SD 93) and 545 (SD 47) ml min-1 1.73 m-2; (2p = 0.06). In the TA group they were 618 (SD 108) and 574 (SD 98) ml min-1 1.73 m-2 (2p = 0.03). The filtration fractions (FFs) in the AA group were 0.244 and 0.246 NS.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of captopril on ambulatory blood pressure, renal and cardiac function in microalbuminuric type 1 diabetic patients

OBJECTIVE

To study the effect of Captopril on ambulatory blood pressure, renal and cardiac function and extracellular volume in microalbuminuric Type 1 diabetic patients.

DESIGN

Randomized, double blind placebo controlled study of two years duration.

SETTING

University clinic.

PATIENTS

Twenty-two patients without hypertension.

INTERVENTION

Patients received 50 mg Captopril or placebo twice a day.

MEASUREMENTS

Ambulatory blood pressure, renal function, extracellular volume, and echocardiographic indices of cardiac function and dimensions were assessed annually. Clinic blood pressure and urinary albumin excretion were measured every 3 months.

RESULTS

Twenty-four hour mean arterial blood pressure was unchanged in the Captopril group (mean +/- SD) (baseline 93 +/- 4 and follow up 91 +/- 8 mmHg) and in the placebo group (96 +/- 7 and 97 +/- 10 mmHg, NS). Night/day ratio of blood pressure was unaffected. Glomerular filtration rate was unchanged and renal plasma flow increased in the Captopril (557 +/- 97 and 600 +/- 112 ml min-1) versus the placebo group (574 +/- 85 and 535 ml min-1, p = 0.05). Filtration fraction was reduced in the Captopril versus the placebo group (p < 0.05). Extracellular volume and echocardiographically derived parameters were unaffected. The relative change in day time mean arterial blood pressure in the Captopril group correlated with changes in urinary albumin excretion (Spearmans r = 0.85, p < 0.05) unlike clinic mean arterial blood pressure (r = 0.33, p = 0.35).

CONCLUSION

Diurnal rhythm of blood pressure was unaffected by long term administration of Captopril. Renal plasma flow was increased and filtration fraction reduced. A significant association between changes in urinary albumin excretion and blood pressure after Captopril was revealed only by the implementation of ambulatory blood pressure measurements.

Homologous pairing is reduced but not abolished in asynaptic mutants of yeast

In situ hybridization was used to examine chromosome behavior at meiotic prophase in the rad50S, hop1, rad50, and spo11 mutants of Saccharomyces cerevisiae, which are defective in chromosome synapsis and meiotic recombination. Painting of chromosomes I and III revealed that chromosome condensation and pairing are reduced in these mutants. However, there is some residual pairing in meiosis, suggesting that homologue recognition is independent of synaptonemal complex formation and recombination. Association of homologues was observed in the rad50, rad50S, and spo11 mutants, which are defective in the formation or processing of meiotic double-strand breaks. This indicates that double-strand breaks are not an essential component of the meiotic homology searching mechanism or that there exist additional or alternative mechanisms for locating homologues.

Schnitzler's syndrome associated with sensorimotor neuropathy

We describe a patient with chronic urticaria in association with monoclonal IgM gammopathy (Schnitzler's syndrome). Seven years after the onset of the cutaneous lesions sensorimotor neuropathy developed. Myelin-associated glycoprotein was detected in the patient's serum. High doses of corticosteroids improved the skin condition but failed to prevent the neuropathy. Six months of treatment with immunoglobulins was without benefit.

[A method for determining the denominator in general practice--results of a pilot study]

In countries with fee for service billing and direct access to specialist care the general practitioner does not know key figures of the population he serves. As the role of general practice in health-service-research, quality assurance activities and the construction of sentinel-networks is becoming more important, valid methods to determine the denominator are needed. Results from five practices suggest that yearly contact groups should be used as a common denominator for general practice in our health care system. For certain groups of patients (e. g. the elderly > 60 yrs.) even quarterly contact groups can give sufficient information to forecast the yearly contact group.

Purification, sequence, and cellular localization of a novel chromosomal protein that binds to methylated DNA

Methylation of mammalian DNA can lead to repression of transcription and alteration of chromatin structure. Recent evidence suggests that both effects are the result of an interaction between the methylated sites and methyl-CpG-binding proteins (MeCPs). MeCP1 has previously been detected in crude nuclear extracts. Here we report the identification, purification, and cDNA cloning of a novel MeCP called MeCP2. Unlike MeCP1, the new protein is able to bind to DNA that contains a single methyl-CpG pair. By staining with an antibody, we show that the distribution of MeCP2 along the chromosomes parallels that of methyl-CpG. In mouse, for example, MeCP2 is concentrated in pericentromeric heterochromatin, which contains a large fraction (about 40%) of all genomic 5-methylcytosine.

Localization of RAP1 and topoisomerase II in nuclei and meiotic chromosomes of yeast

Topoisomerase II (topoII) and RAP1 (Repressor Activator Protein 1) are two abundant nuclear proteins with proposed structural roles in the higher-order organization of chromosomes. Both proteins co-fractionate as components of nuclear scaffolds from vegetatively growing yeast cells, and both proteins are present as components of pachytene chromosome, co-fractionating with an insoluble subfraction of meiotic nuclei. Immunolocalization using antibodies specific for topoII shows staining of an axial core of the yeast meiotic chromosome, extending the length of the synaptonemal complex. RAP1, on the other hand, is located at the ends of the paired bivalent chromosomes, consistent with its ability to bind telomeric sequences in vitro. In interphase nuclei, again in contrast to anti-topoII, anti-RAP1 gives a distinctly punctate staining that is located primarily at the nuclear periphery. Approximately 16 brightly staining foci can be identified in a diploid nucleus stained with anti-RAP1 antibodies, suggesting that telomeres are grouped together, perhaps through interaction with the nuclear envelope.

Modification of the amount of cholesterol in hepatic steatosis induced in susceptible and resistant mice infected with MHV3: a biochemical and ultrastructural study

A mouse hepatitis virus-3 strain subcultured in our laboratory is a unique experimental model in which to study virus-induced liver steatosis. This strain produces massive lipid deposition not only in sensitive adult BALB/c mice but also (though less extensive) in virus-resistant adult A/J mice. Biochemical determinations have shown that this steatosis is characterized by an increased amount of neutral lipids (sterols and triglycerides) in infected livers of BALB/c mice and by a smaller increase in those of A/J mice. However, the relative percentage of cholesterol and triglycerides is similar in both strains. Liver phospholipid content was significantly decreased in both strains of mice. To discriminate between cytoplasmic and membrane cholesterol content in different types of liver cells, an ultrastructural study was performed with filipin, a specific cholesterol marker. This study shows on one hand an important increase in the cholesterol in the hepatocytes of BALB/c mice and a smaller increase in those of A/J mice, in agreement with biochemical data. However, marked cholesterol decrease and abnormal cholesterol distribution were observed in the endothelial liver cells of infected BALB/c mice. This decreased cholesterol content probably led to higher fluidity of these membranes, which could be related to the important drop in the number of endothelial cell fenestrae observed after mouse hepatitis virus-3 infection. Because in A/J infected mice neither a decrease in the amount and distribution of cholesterol nor decreased fenestration were observed in endothelial liver cells, these findings could be correlated with the resistance of these mice to the infection.

Prolonged increase of corticosterone secretion by chronic social stress does not necessarily impair immune functions

The influence of a chronic social stress upon immunity was investigated in Wistar rats, submitted for four weeks to two different behavioral situations, balanced in a factorial design: housing with three females and membership rotation. The combination of these two factor led to adrenal enlargement (43.3%), thymus involution (39.5%) and increased basal corticosterone levels, all indices of activation of the hypothalamic-hypophysis-adrenal axis. However, neither natural killer cell activity, splenocyte reactivity to mitogen nor the rate of spontaneous development of antibodies against Mycoplasma pulmonis, a common pathogen of the respiratory tract, were changed in the endocrine activated animals. Analysis of the data on kinetics of stress at 1, 7 and 28 days after the initial mixing of the animals gave the same results. These data question the immunosuppressant activity usually conferred to corticosteroids, at least when adrenal hyperactivity is induced by chronic environmental stressors.

Gender bias against and sexual harassment of AMWA members in Massachusetts

Despite the increasing participation of women in medicine over the past few decades, hindrances to professional advancement for women physicians and medical students persist. The present study sought to assess the prevalence of gender bias and sexual harassment in a sample of women physicians and medical students. Within a one-year period, 54% of respondents encountered some form of sex discrimination. In addition, approximately one-fourth experienced sexual harassment (27%) and/or discrimination related to parenthood (24%). Unwanted sexual attention not viewed as sexual harassment was experienced by more than twice as many respondents (55%). Other forms of discrimination were reported as well: age (22%), sexual preference (20%), and race (7%). Perceptions of the extent of sex discrimination and sexual harassment, of their impact on professional commitment, and of the adequacy of solutions at institutions varied directly with whether or not respondents had experienced some form of employment discrimination within the past 12 months. This study points to the need for clarification of what constitutes sexual harassment and for the creation of safe, effective mechanisms to remedy and prevent all forms of gender bias.

Relationship between allozymes, heterozygosity and morphological characters in red deer (Cervus elaphus), and the influence of selective hunting on allele frequency distribution

Morphological characters in red deer (Cervus elaphus), which serve as criteria for selective hunting, were examined in relation to electrophoretic variation in three populations from the Vosges in eastern France. From the polymorphic loci examined, certain alleles at Idh-2, Me-1 and Acp-1 showed significant associations with a special development of body and antler characters selected for by hunters. Idh-2(125) was associated with larger hind foot length in females and a higher number of antler points in males. Me-1(90) and Acp-1(100) were associated with small spikes. The populations studied differed from one another in the duration and intensity of selective hunting and the increase or decrease in the respective allele frequencies could be explained by selection for large body size, a high number of antler points and against small spikes in yearlings, rather than by genetic drift. Among other morphological characters examined, the length of the main beam was significantly associated with the allele Acp-2(100). In contrast, no associations could be detected between overall heterozygosity and the development or the degree of asymmetry (in paired structures) of any of the morphological traits in question. Although no obvious differences in the overall values of polymorphism or heterozygosity were found between the populations, selective hunting leads towards a change in allele frequencies and eventually to the loss of one or the other rare allele.

Meiotic chromosome synapsis in a haploid yeast

An extensive synaptonemal complex (SC) is found at pachytene in whole mount spread preparations of a haploid yeast, Saccharomyces cerevisiae, strain. Whereas unsynapsed axial elements are present only in a few nuclei, in others non-homologous synapsis involves virtually the whole chromosome set. This suggests that homology is not an indispensable precondition for SC formation in yeast but that chromosomes engage in non-homologous synapsis if no homologous partner is available. Recent evidence that in the sporulation deficient yeast mutants rad50 and mer1 axial elements do form but remain unsynapsed in the majority of nuclei is discussed in the light of the above findings.

Comparative study of test kits for measurement of rheumatoid factors by the latex fixation test

The performance of 14 test kits for the measurement of rheumatoid factors by the latex fixation test was investigated; all results were expressed in IU/ml. Reproducibility and properties of control sera were also studied. It was found that half of the kits did not satisfactorily detect rheumatoid factor levels lower than 25 IU/ml. Most kits performed reasonably well in practice. Positive control sera only rarely met strict requirements. The relative costs did not always have a clear correlation with the quality of the results. The variation caused by differences between kits became acceptable when the results were expressed in IU/ml.

Pedigree analyses of yeast cells recovering from DNA damage allow assignment of lethal events to individual post-treatment generations

Haploid cells of Saccharomyces cerevisiae were treated with different DNA damaging agents at various doses. A study of the progeny of individual such cells (by pedigree analyses up to the third generation) allowed the assignment of lethal events to distinct post treatment generations. By microscopically inspecting those cells which were not able to form visible colonies we could discriminate between cells dying from immediately effective lethal hits and those generating microcolonies (three to several hundred cells) probably as a consequence of lethal mutation(s). The experimentally obtained numbers of lethal events (which we call apparent lethal fixations) were mathematically transformed into mean probabilities of lethal fixations as taking place in cells of certain post treatment generations. Such analyses give detailed insight into the kinetics of lethality as a consequence of different kinds of DNA damage. For example, X-irradiated cells lost viability mainly by lethal hits (which we call 00-fixations); only at a higher dose also lethal mutations fixed in the cells that were in direct contact with the mutagen (which we call 0-fixations), but not in later generations, occurred. Ethyl methanesulfonate (EMS)-treated cells were hit by 00-fixations in a dose dependent manner; 0-fixations were not detected for any dose of EMS applied; the probability for fixation of lethal mutations was found equally high for cells of the first and second post treatment generation and, unexpectedly, was well above control in the third post-treatment generation. The distribution of all sorts of lethal fixations taken together, which occurred in the EMS-damaged cell families, was not random.(ABSTRACT TRUNCATED AT 250 WORDS)

Twenty-five years of renal trauma at a teaching hospital

In a study of 535 patients with renal trauma admitted to the Medical College of Virginia Hospitals from 1962 to 1988, the authors found indications of a decrease in the rate of total nephrectomy in patients with blunt trauma, due in part to advances in diagnostic technology. In the cases of gunshot wounds, however, a persistently high rate of nephrectomy prevailed, reflecting, the authors believe, the proliferation of increasingly lethal weaponry.