Upper airway muscle activity in normal women: influence of hormonal status

Obstructive sleep apnea is a disorder with a strong male predominance. One possible explanation could be an effect of female hormones on pharyngeal dilator muscle activity. Therefore, we determined the level of awake genioglossus electromyogram (EMGgg) and upper airway resistance in 12 pre- and 12 postmenopausal women under basal conditions and during the application of an inspiratory resistive load (25 cmH2O . l-1 . s). In addition, a subgroup of eight postmenopausal women were studied a second time after 2 wk of combined estrogen and progesterone replacement in standard doses. Peak phasic and tonic genioglossus activity, expressed as a percentage of maximum, were highest in the luteal phase of the menstrual cycle (phasic 23.9 +/- 3.8%, tonic 10.2 +/- 1.0%), followed by the follicular phase (phasic 15.5 +/- 2.2%, tonic 7.3 +/- 0.8%), and were lowest in the postmenopausal group (phasic 11.3 +/- 1.6%, tonic of 5.0 +/- 0.6), whereas upper airway resistance did not differ. There was a weak but significant positive correlation between progesterone levels and both peak phasic (P < 0.05) and tonic (P < 0.01) EMGgg. Finally, there was a significant increase in EMGgg in the postmenopausal group restudied after hormone therapy. In conclusion, female hormones (possibly progesterone) have a substantial impact on upper airway dilator muscle activity.     

Manipulating photosynthesis

The levels of individual photosynthetic proteins can be independently decreased by the Agrobacterium-mediated transformation of plants with antisense RNA constructs. Protocols for the introduction of such constructs into Agrobacterium, the Agrobacterium-mediated transformation of tobacco leaf disks, and the screening and analysis of the transgenic plants produced are described.     

Tumors arising in the palpebral lobe of the lacrimal gland

PURPOSE: Tumors arising in the palpebral lobe of the lacrimal gland are uncommon. There have been only eight reported patients, all of whom had pleomorphic adenomas. The authors present another six patients with primary palpebral lobe tumors. METHODS: The clinical presentation, computed tomographic, and pathologic findings of these six patients were reviewed. RESULTS: Tumor types include three pleomorphic adenomas, one well-differentiated adenoid cystic carcinoma, one carcinoma in pleomorphic adenoma, and one carcinoma ex pleomorphic adenoma. All six patients presented with a painless mass in the upper outer eyelid without significant displacement of the globe, but the superficial location of these lesions led to early detection. The tumors were localized to the lacrimal gland, predominantly anterior to the orbital rim. In all six patients, the involved palpebral lobe was removed, five via a direct anterior subcutaneous approach and one by superolateral orbitotomy. In two patients (adenoid cystic carcinoma and carcinoma ex pleomorphic adenoma), repeat surgery via superolateral orbitotomy was necessary to achieve complete removal of the lacrimal gland and surrounding tissue. No recurrences were detected during follow-up (range, 6 months to 7 years; mean, 26 months). CONCLUSION: Palpebral lobe tumors of the lacrimal gland are more common and consist of a greater variety of histologic types than previously described. In our series, these tumors comprise 17% of all epithelial lacrimal gland lesions. These are the first reported cases of malignancy in this location. A longer follow-up period is necessary to determine the true recurrence rate of these tumors.     

Cariogenicity depends more on diet than the prevailing mutans streptococcal species

This review aims to compare the occurrence and distribution of mutans streptococci in Africa, Europe, and North America and in addition will try to offer explanations for existing relationships among salivary mutans streptococci counts, dietary patterns, and dental caries. The literature reveals that salivary mutans streptococci counts in child populations of the three continents are comparable. The distribution of mutans streptococci species, with a predominance of S. mutans followed by S. sobrinus, and the virtual absence of other mutans streptococci species are also comparable. Although it is widely believed that diet has an important effect on mutans streptococci counts, this review provides evidence that this does not hold true when variations in dietary patterns are moderate, as they normally are in real-life situations. Since the diets of the child populations in the three continents vary moderately, a strong dietary-induced effect on salivary mutans streptococci counts cannot be expected. The observed analogous salivary mutans streptococci counts in these child populations are thus 'not surprising' but are in accordance with the conceptual expectation. The differences in caries experience in children of the three continents cannot be explained by the prevailing mutans streptococci species but instead should be attributed to differences in the cariogenicity of the various diets. The fact that the cariogenicity of the diet determines the development of dental caries while hardly affecting the mutans streptococci counts explains the limited value of the latter as an indicator of dental caries. The reviewed literature shows that mutans streptococci are ubiquitous in children aged 7 years and older in Africa, Europe, and North America. Mutans streptococci should therefore be considered as belonging to the indigenous microflora of the human mouth.     

Short-term and long-term cytokine release by mouse bone marrow mast cells and the differentiated KU-812 cell line are inhibited by brefeldin A

Mast cells and basophils produce a wide range of cytokines, including large amounts of both IL-6 and granulocyte-macrophage CSF (GM-CSF). However, the route by which cytokines are secreted is poorly understood. In the current study, we used two inhibitors of vesicular transport, brefeldin A and monensin, to examine the routes of secretion of IL-6 and GM-CSF in the differentiated KU812 human cell line and cultured mouse bone marrow mast cells (mBMMC). Studies of cytokine production over 6 to 24 h demonstrated that IL-6 and GM-CSF release from both cell types were inhibited by brefeldin A (BFA) following activation with calcium ionophore, A23187. Monensin had similar inhibitory effects to that of BFA on the initial and ongoing IL-6 release from KU812 cells. In contrast, the amount of each cytokine remaining within the cells was significantly enhanced. Similar results were obtained following IgE-mediated activation of mBMMC. BFA significantly inhibited both the constitutive secretion of IL-6 and the immediate ionophore-induced increase in IL-6 release from KU812 cells at 20 min postactivation. However, treatment with these agents did not alter the release of histamine and beta-hexaminidase from either mBMMC or KU812 cells. These studies suggest that both the initial 20-min release of IL-6 and secretion of IL-6 and GM-CSF over up to 24 h by mBMMC and differentiated KU-812 cells occur predominately through a vesicular transport-dependent mechanism, and that little, if any, IL-6 and GM-CSF is released through degranulation.     

Sexual behavior among U.S. high school students, 1990-1995

CONTEXT: High rates of unintended pregnancy and sexually transmitted diseases (STDs), including HIV infection, among adolescents are major public health concerns that have created interest in trends in teenage sexual activity. METHODS: Nationally representative data from Youth Risk Behavior Surveys conducted in 1990, 1991, 1993 and 1995 are used to examine levels of sexual experience, age at first intercourse, current sexual activity and condom use at last intercourse among students in grades 9-12. RESULTS: The proportion of students who reported being sexually experienced remained at 53-54% from 1990 through 1995, while the percentage of sexually active students who used condoms at last intercourse rose from 46% to 54% between 1991 and 1995. Black students were more likely than white students to report being sexually experienced, being currently sexually active and having had four or more lifetime sexual partners; black students also reported a significantly younger age at first intercourse. Gender differences in sexual behavior were found more frequently among black students than among white or Hispanic students. CONCLUSIONS: Although levels of sexual experience for high school students in the United States have not risen during the 1990s, a very high percentage of students continue to be at risk for unintended pregnancy and STDs, including HIV infection.     

Tritiated-naloxone binding to brainstem opioid receptors in the sudden infant death syndrome

The sudden infant death syndrome (SIDS) is defined as the sudden death of an infant under 1 year of age that remains unexplained after a thorough case investigation, including a complete autopsy. We hypothesized that SIDS is associated with altered 3H - naloxone binding to opioid receptors in brainstem nuclei related to respiratory and autonomic control. We analyzed 3H - naloxone binding in 21 regions in SIDS and control brainstems using quantitative tissue receptor autoradiography. Three groups were analyzed: SIDS (n = 45); acute controls (n = 14); and a chronic group with oxygenation disorders (n = 15). Opioid binding was heavily concentrated in the caudal nucleus of the solitary tract, nucleus parabrachialis medialis, spinal trigeminal nucleus, inferior olive, and interpeduncular nucleus in all cases analyzed (n = 74). The arcuate nucleus on the ventral medullary surface contained negligible binding in all cases (n = 74), and therefore binding was not measurable at this site. We found no significant differences among the three groups in the age-adjusted mean 3H - naloxone binding in 21 brainstem sites analyzed. The only differences we have found to date between SIDS and acute controls are decreases in 3H - quinuclidinyl benzilate binding to muscarinic cholinergic receptors and in 3H - kainate binding to kainate receptors in the arcuate nucleus in alternate sections of this same data set. The present study suggests that there is not a defect in opioid receptor binding in cardiorespiratory nuclei in SIDS brainstems.     

Identification of novel susceptibility loci for inflammatory bowel disease on chromosomes 1p, 3q, and 4q: evidence for epistasis between 1p and IBD1

The idiopathic inflammatory bowel diseases, Crohn's disease (CD) and ulcerative colitis (UC), are chronic, frequently disabling diseases of the intestines. Segregation analyses, twin concordance, and ethnic differences in familial risks have established that CD and UC are complex, non-Mendelian, related genetic disorders. We performed a genome-wide screen using 377 autosomal markers, on 297 CD, UC, or mixed relative pairs from 174 families, 37% Ashkenazim. We observed evidence for linkage at 3q for all families (multipoint logarithm of the odds score (MLod) = 2.29, P = 5.7 x 10(-4)), with greatest significance for non-Ashkenazim Caucasians (MLod = 3.39, P = 3.92 x 10(-5)), and at chromosome 1p (MLod = 2.65, P = 2.4 x 10(-4)) for all families. In a limited subset of mixed families (containing one member with CD and another with UC), evidence for linkage was observed on chromosome 4q (MLod = 2.76, P = 1.9 x 10(-4)), especially among Ashkenazim. There was confirmatory evidence for a CD locus, overlapping IBD1, in the pericentromeric region of chromosome 16 (MLod = 1.69, P = 2.6 x 10(-3)), particularly among Ashkenazim (MLod = 1.51, P = 7.8 x 10(-3)); however, positive MLod scores were observed over a very broad region of chromosome 16. Furthermore, evidence for epistasis between IBD1 and chromosome 1p was observed. Thirteen additional loci demonstrated nominal (MLod > 1.0, P < 0.016) evidence for linkage. This screen provides strong evidence that there are several major susceptibility loci contributing to the genetic risk for CD and UC.     

Open access gastroscopy--3 year experience of a new service

The paper discusses a case of 50-year-old male admitted to the hospital with symptoms of respiratory failure. The patient had previously been treated for pneumonia. After the admission, control-assisted ventilation was introduced and a swab from endotracheal tube was taken for microbiological examination, as well as pefloxacin, dexamethasone, Ambroxol and heparin treatment was administered. Patients condition improved. After several days respiratory failure intensified, requiring repeated artificial ventilation. According to the obtained antibiogram, Tienam was administered with favourable results. During the therapy with Tienam no side-effects were observed. Based on chest X-ray examination and data from interview, infection of multiple congenital bronchogenic cysts was diagnosed.     

Effect of yohimbine on nerve growth factor mRNA and protein levels in rat hippocampus

Activation of noradrenergic receptors has been shown to increase expression of nerve growth factor (NGF) gene in brain cells in vitro. The present studies were undertaken to determine if this stimulation was effective in vivo as well. Rats were administered the norepinephrine-releasing drug, yohimbine (YOH), and had their hippocampi assayed for NGF mRNA and protein at various times after the injection. It was found that yohimbine caused a 3-fold increase of NGF mRNA levels at 24 h. Protein levels, however, were unaltered at this time. Thus norepinephrine release in vivo appears to be sufficient for increasing mRNA level but not for translation to protein.