Quantitative trait locus mapping of human blood pressure to a genetic region at or near the lipoprotein lipase gene locus on chromosome 8p22

Resistance to insulin-mediated glucose disposal is a common finding in patients with non-insulin-dependent diabetes mellitus (NIDDM), as well as in nondiabetic individuals with hypertension. In an effort to identify the generic loci responsible for variations in blood pressure in individuals at increased risk of insulin resistance, we studied the distribution of blood pressure in 48 Taiwanese families with NIDDM and conducted quantitative sib-pair linkage analysis with candidate loci for insulin resistance, lipid metabolism, and blood pressure control. We found no evidence for linkage of the angiotensin converting enzyme locus on chromosome 17, nor the angiotensinogen and renin loci on chromosome 1, with either systolic or diastolic blood pressures. In contrast, we obtained significant evidence for linkage or systolic blood pressure, but not diastolic blood pressure, to a genetic region at or near the lipoprotein lipase (LPL) locus on the short arm of chromosome 8 (P = 0.002, n = 125 sib-pairs, for the haplotype generated from two simple sequence repeat markers within the LPL gene). Further strengthening this linkage observation, two flanking marker loci for LPL locus, D8S261 (9 cM telomeric to LPL locus) and D8S282 (3 cM centromeric to LPL locus), also showed evidence for linkage with systolic blood pressure (P = 0.02 and 0.0002 for D8S261 and D8S282, respectively). Two additional centromeric markers (D8S133, 5 cM from LPL locus, and NEFL, 11 cM from LPL locus) yielded significant P values of 0.01 and 0.001, respectively. Allelic variation around the LPL gene locus accounted for as much as 52-73% of the total interindividual variation in systolic blood pressure levels in this data set. Thus, we have identified a genetic locus at or near the LPL gene locus which contributes to the variation of systolic blood pressure levels in nondiabetic family members at high risk for insulin resistance and NIDDM.     

Droloxifene does not blunt bone anabolic effects of prostaglandin E2, but maintains prostaglandin E2-restored bone in aged, ovariectomized rats

The authors examined 1) effects of nortriptyline (NT) on electroencephalographic (EEG) sleep measures in elderly patients with bereavement-related depression in remission under randomized, double-blind, placebo-controlled conditions, and 2) the effects of clinical remission on sleep after discontinuation of medication. Subjects were classified as responders to placebo (n = 9) or NT (n = 18) and had EEG sleep studies at three time-points: before treatment (T1), remitted on medication or placebo (T2), and remitted off medication or placebo (T3). As compared with placebo, NT was differentially associated with decreases in REM sleep time and percent and increases in REM sleep density (T2). No changes in EEG sleep measures occurred in placebo responders. REM sleep measures in NT responders reverted to T1 levels after T3, with persistence of robust clinical remission and normal subjective sleep quality. These data suggest that NT alters REM sleep, but that EEG sleep characteristics in bereavement-related depression persist into remission.     

Si和Si尖上纳米金刚石场电子发射性质的研究

研究了Si和Si尖上纳米金刚石场电子发射性质。纳米金刚石是利用热灯丝CVD法合成的，反应气体是CH4、N2和H2的混合物。实验结果表明Si衬底上的纳米金刚石特别是Si尖上的金刚石与多晶金刚石相比，前者极大地改善了场发射性质。场发射电场阈值和电流与金刚石晶粒度密切相关。文中对其结果进行了讨论。     

Apoptosis and expression of inducible nitric oxide synthase are mutually exclusive in renal mesangial cells

Nitric oxide (NO) is a multipurpose messenger molecule, important for blood vessel relaxation, neuronal communication, and antimicrobial activities. The generation of NO from L-arginine is catalyzed by NO synthase (NOS). An inducible form of NOS, iNOS, was first characterized in macrophages and then in many other tissues and cells, including renal mesangial cells. Mesangial cells play a crucial role in the regulation of the glomerular filtration rate as well as in the pathophysiology of certain forms of glomerulonephritis in which mesangial cells and macrophages produce NO in high amounts. Because reports have associated NO production with apoptotic cell death in macrophages and we recently demonstrated NO-mediated apoptosis in mesangial cells, we searched for the relationship between in situ iNOS induction and apoptosis by iNOS immunocytochemistry and terminal desoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) staining. RAW 264.7 macrophages exhibited homogeneous iNOS expression and apoptotic nuclei in the iNOS-containing cells upon stimulation with interferon-gamma and lipopolysaccharide. In contrast, stimulated rat mesangial cells stained heterogeneously for iNOS, depending on cell passage and iNOS-stimulating pathway. Mesangial cells expressing iNOS did not display signs of apoptosis and, vice versa, cells showing characteristic features of apoptosis did not stain for iNOS. Thus, our study suggests that mesangial cells react to stimulation by interleukin-1 and/or cAMP-elevating compounds with mutually exclusive responses, either by expression of iNOS or by undergoing programmed cell death.     

Selective loss of pallidal dopamine D2 receptor density in hepatic encephalopathy

The binding parameters of [3H]SCH 23390 and [3H]spiperone (radioligands for dopamine D1 and D2 receptors, respectively) were investigated in autopsied frontal cortex, caudate nucleus and globus pallidus/putamen of cirrhotic patients who died in hepatic coma as well as in age- and sex-matched controls. Specific [3H]SCH 23390 binding site densities were unchanged in all regions; in contrast, specific [3H]spiperone binding site density was decreased (by 44%, P < 0.001) in the globus pallidus/putamen of patients with HE. Decreased densities of pallidal D2 binding sites could relate to the motor dysfunctions commonly encountered in human HE.     

Sustained ventricular tachycardia in older children. Spontaneous regression in 3 cases]

Extensively described since Gallvardin's reports, the electrical features of salves of ventricular tachycardia in an apparently healthy heart are now well known. The usual benign nature of this arrhythmia is acknowledged, seldom contradicted by isolated clinical cases. Although chronicity is the rule in young adults, there have been a few publications concerning the natural history of these tachycardias in the paediatric age group. The authors report three cases of episodic sustained ventricular tachycardia in older children, presenting at an average of 7 years of age (range 5 to 9 years) and followed up for an average of 7 years (range: 5.5 to 9 years). These three children were treated for an average of 4.5 years (range: 3 to 5.5 years). All treatment was finally withdrawn when stable permanent sinus rhythm without ventricular extrasystoles was restored and confirmed over an average period of 2 years (range 10 months to 3.5 years), an average of 4 (range 3 to 7) successive normal Holter recordings at several months' interval. The outcome in children to spontaneous regression after several years would seem to make radiofrequency ablation more dangerous than useful given the benign nature of the arrhythmia and its good response to pharmacological intervention.     

Respiratory-related control of extrinsic tongue muscle activity

The purpose of this brief report is to introduce new evidence showing that the protrudor and retractor muscles of the tongue are co-activated during inspiration in eupnea and hyperpnea in an anesthetized, tracheotomized rat model. We also review previous work on the respiratory related control of the tongue musculature, and briefly consider the clinical significance of this work. The important new findings are that: (1) Both hypoxia and hypercapnia cause parallel increases in drive to the tongue protrudor and retractor muscles (the genioglossus and hyoglossus muscles, respectively); (2) phasic volume feedback inhibits the peak inspiratory activity of both muscles; and (3) the tongue muscles consistently produce a retraction force when the genioglossus and hyoglossus are co-activated, in both animal and human subjects. This latter observation is consistent with previous work showing that the retractor muscles (hyoglossus and styloglossus) develop up to ten times more force than the genioglossus muscle. The possible mechanical consequences of tongue muscle co-activation are briefly considered.     

Adequacy and efficacy of lateral cervical spine radiography in alert, high-risk blunt trauma patient

OBJECTIVE: The purpose of this study was to determine the adequacy and accuracy of lateral cervical spine radiographs in the initial evaluation of alert, high-risk trauma patients evaluated at a Level I trauma center. METHODS: Data were obtained retrospectively through review of trauma service admissions from January 1, 1994, to July 31, 1995. Included were all patients triaged to a trauma response team with age > 15 years, Glasgow Coma Scale score > 13, and blunt mechanism of injury. Lateral cervical spine radiograms were obtained routinely before secondary survey and were reviewed for technical adequacy (all seven cervical vertebrae, C7/T1 interspace). The presence of cervical symptoms (pain, tenderness, neurologic deficits) was recorded. Sensitivity and specificity were calculated for lateral cervical spine radiography and cervical symptoms in predicting the presence of cervical spine injury. Bayesian analysis, which allows for the current probability of occurrence to be factored by previously reported probabilities of occurrence, was used to determine the negative predictive probability of lateral cervical spine radiography and absence of cervical symptoms to predict the absence of injury to the cervical spine. RESULTS: Three hundred fifty-three patients received lateral cervical spine radiograms, of which 223 (63%) were determined to be adequate for interpretation. Cervical symptoms were present in 77 patients (20%). Only 32 (42%) of this group's lateral cervical spine radiograms were adequate. Nine patients (2.4%) had acutely fractured cervical vertebrae or ligamentous disruption. Lateral cervical spine radiography showed the injury in only six of these patients. The sensitivity, specificity, and negative predictive probability for lateral cervical spine radiography were 67, 58, and 1.4%, respectively, and for absence of cervical symptoms, 89, 81, and 0.32%, respectively. CONCLUSION: The higher accuracy and lower negative predictive probability make the absence of cervical symptoms in the alert, high-risk, blunt trauma patient a better screening test than lateral cervical spine radiography. We suggest that lateral cervical spine radiography is not needed in the initial evaluation of alert patients who have sustained blunt trauma.