Scattering-driven PPG signal model

This article discusses the origin of PPG signals. Two plausible hypotheses are analyzed: the volumetric hypothesis and a model wherein the PPG is driven by the RBC aggregation process. To verify the model predictions, the PPG signals at the fingertip were measured. External pressure was applied to the fingertip, presumably reducing the blood flow. The results expressed in terms of gamma, used in pulse-oximetry, agree with the aggregation model. In addition, the oscillometric signal and the PPG signal amplitude were simultaneously measured in the fingertip. All of the experimental results favor the proposed aggregation mechanism as responsible the PPG signal.     

乙稀雌酚肌注致心房纤颤1例

1　病例报告　男 ,71岁 ,因排尿困难于 1999- 0 9- 0 4入院 .B超确诊前列腺增生 5 a,既往无高血压、心脏病及心率失常史 .查体 :Bp17/ 10 k Pa,心界不大 ,心率 6 2次· min- 1 ,心律齐 .下腹部可触及涨大的膀胱 ,约耻骨上 4指 .入院时 ECG正常 .肝肾功能无异常 ,确诊前列腺增生伴急性尿潴留 .首先予导尿 ,导出尿液约 90 0 m L,之后 im乙稀雌酚 1mg,2 h后患者突发心慌、胸闷、气短、心前区疼痛 .发现患者大汗BP12 /6 k Pa,P110次· min- 1 ,R2 8次· min- 1 ,心率绝对不齐 ,脉搏明显短促 ,两肺底可闻及湿性罗音及哮鸣音 ,ECG示房颤 ,心…     

Long-term protection of hematopoiesis against the cytotoxic effects of multiple doses of nitrosourea by retrovirus-mediated expression of human O6-alkylguanine-DNA-alkyltransferase

A human O6-alkylguanine-DNA-alkyltransferase (ATase) cDNA-containing retrovirus was used to infect murine long-term primary bone marrow cultures. High levels of ATase expression were obtained, and colony- forming cells of the granulocyte-macrophage lineage from the cultures transduced with the human ATase retrovirus were three times more resistant to the alkylating agent, N-methyl-N-nitrosourea (MNU), than control cultures. Furthermore, expression of the human ATase protected long-term hematopoiesis, measured as the output of progenitor cells to the nonadherent fraction of the culture, against the cytotoxic effects of repeated exposures to MNU. These results clearly show that a human ATase cDNA-containing retrovirus can be used to infect long-term primary bone marrow cultures and that this attenuates their sensitivity to nitrosoureas.     

Mycophenolate mofetil as the primary treatment of membranous lupus nephritis with and without concurrent proliferative disease: a retrospective study of 29 cases

Studies of immunosuppressive therapy, particularly mycophenolate mofetil (MMF), in membranous lupus nephritis (MLN) are limited. We report on our experience with primary (first-line) MMF therapy to induce and sustain renal remission in MLN with and without a concurrent proliferative lesion. Systemic lupus erythematosus (SLE) patients were studied, retrospectively, if treated with MMF for newly diagnosed MLN. Complete remission was defined as proteinuria less than 0.5 g/24 h, inactive urine sediment and normal estimated glomerular filtration rate. Response in pure MLN (Group I, n=10) was compared with mixed MLN and proliferative lupus nephritis (Group II, n=19). By 12 months, 4 (40%) patients in Group I and 7 (36.8%) in Group II achieved complete remission (P=0.87). One (10%) patient in Group I and 2 (10.5%) in Group II had worsening renal disease (P=0.97). Mean time to remission was more than seven months in both groups. The remaining patients had stable disease without improvement or worsening. Only 2 of 11 achieving initial remission had a relapse with an average of 28 months of follow-up after remission. Self-limited gastrointestinal symptoms occurred in 12 patients, none requiring withdrawal of the drug. Mycophenolate mofetil as a primary therapy in MLN was successful in inducing complete remission in about 40% of MLN, particularly in patients with mild proteinuria. However, 12 months of therapy was necessary for best outcomes. Response rate was not different in the presence or absence of a proliferative lesion.     

Individual, household and community factors associated with HIV test refusal in rural Malawi

Objective To investigate individual, household and community factors associated with HIV test refusal in a counselling and testing programme offered at population level in rural Malawi. Methods HIV counselling and testing was offered to individuals aged 18–59 at their homes. Individual variables were collected by interviews and physical examinations. Household variables were determined as part of a previous census. Multivariate models allowing for household and community clustering were used to assess associations between HIV test refusal and explanatory variables. Results Of 2303 eligible adults, 2129 were found and 1443 agreed to HIV testing. Test refusal was less likely by those who were never married [adjusted odds ratio (aOR) 0.50 for men (95% CI 0.32; 0.80) and 0.44 (0.21; 0.91) for women] and by farmers [aOR 0.70 (0.52; 0.96) for men and 0.59 (0.40; 0.87) for women]. A 10% increase in cluster refusal rates increased the odds of refusal by 1.48 (1.32; 1.66) in men and 1.68 (1.32; 2.12) in women. Women counsellors increased the odds of refusal by 1.39 (1.00; 1.92) in men. Predictors of HIV test refusal in women were refusal of the husband as head of household [aOR 15.08 (9.39; 24.21)] and living close to the main road [aOR 6.07 (1.76; 20.98)]. Common reasons for refusal were fear of testing positive, previous HIV test, knowledge of HIV serostatus and the need for more time to think. Conclusion Successful VCT strategies need to encourage couples counselling and should involve participation of men and communities.     

Prognostic implications of renal hypertrophy in diabetes mellitus

Early in the course of type 1 diabetes mellitus, hypertrophy of the kidney is a consistent finding that is easily diagnosed using current noninvasive methods, especially ultrasonography. Renal functional changes occur in association with hypertrophy, most notably glomerular hyperfiltration. The structural counterpart of this functional change is an early increase in capillary filtration surface area. In most forms of nondiabetic renal hypertrophy, kidney size is closely linked to GFR. In contrast, in diabetes, persistence of hypertrophy after the clinical onset of overt kidney disease (microalbuminuria, hypertension, decreased GFR, etc.) suggests that sustained release of one or more growth factors may continue even after kidney function declines. The fact that growth factors can act in both an autocrine and paracrine fashion raises the possibility that the local effects of such substances may act as local mediators of kidney growth. Failure of renal hypertrophy to reverse following strict glycemic control for a few months may turn out to be an important prognostic indicator of future progression of the renal disease, but this remains to be established. Prospective studies of kidney size in patients with newly diagnosed type 1 diabetes, using accurate noninvasive methods, may be helpful in establishing whether irreversible ("autonomous") hypertrophy of the kidney is indeed a useful prognostic indicator. As therapies are developed that target the different microvascular complications of diabetes (retinopathy, nephropathy, neuropathy), a noninvasive estimation of kidney size may be a cost-effective method of predicting ultimate renal involvement. Since microalbuminuria occurs relatively late in the disease process, early and persistent hypertrophy of the kidney may become a useful prognostic test in the earliest stages of the disease.