Women with advanced pelvic organ prolapse and levator ani muscle avulsion would significantly benefit from mesh repair surgery

OBJECTIVES

Mesh repair surgery for pelvic organ prolapse (POP) has been suspended in some countries owing to concerns about its associated complications. However, mesh repair has been shown to reduce the risk of prolapse recurrence after surgery. In view of this controversy, our aim was to assess the incidence of subjective and objective recurrence of POP following mesh repair surgery vs native-tissue repair in women with Stage-III or Stage-IV POP.

METHODS

This was a prospective observational study of women who presented with Stage-III or Stage-IV POP and received primary prolapse surgery between 2013 and 2018. Transperineal ultrasound was performed before the operation and volumes were analyzed offline to assess the presence of levator ani muscle (LAM) avulsion. All women were counseled on either mesh repair or native-tissue reconstruction. The mesh-repair group was followed up for up to 5 years and the native-tissue-repair group for up to 2 years after the operation. Prolapse symptoms and POP quantification (POP-Q) staging were assessed at follow-up. Subjective recurrence of POP was defined as symptoms of prolapse (vaginal bulge sensation or dragging sensation) reported by the patient. Objective recurrence was defined as POP-Q ≥ Stage II. The subjective and objective recurrences of prolapse were compared between women with and those without mesh use. Multivariate regression analysis was used to identify risk factors for the recurrence of POP.

RESULTS

A total of 154 Chinese women with Stage-III or Stage-IV prolapse were recruited. Of these, 104 (67.5%) underwent mesh repair (transabdominal in 57 women and transvaginal in 47 women) and 50 (32.5%) had native-tissue repair surgery. Ninety-five (61.7%) women had LAM avulsion. Both the subjective POP recurrence rate (4.8% vs 20.0%; P = 0.003) and the objective recurrence rate (20.2% vs 46.0%; P = 0.001) were significantly lower in the mesh-repair group than in the native-tissue-repair group. On multivariate logistic regression analysis, mesh repair was associated significantly with a reduced risk of subjective recurrence (odds ratio (OR), 0.20 (95% CI, 0.07-0.63)) and of objective recurrence (OR, 0.16 (95% CI, 0.07-0.55)) of prolapse. On subgroup analysis of women with LAM avulsion, mesh repair significantly reduced the risk of subjective recurrence (OR, 0.24 (95% CI, 0.07-0.87)) and objective recurrence (OR, 0.23 (95% CI, 0.09-0.57)) of POP. The incidence of mesh-related complications was low, and mesh exposure could be treated conservatively or by minor surgery.

CONCLUSIONS

Mesh repair surgery, compared with native-tissue repair, was associated with a 5-fold reduction in the risk of subjective recurrence and a 6-fold reduction in the risk of objective recurrence of prolapse in women with Stage-III or Stage-IV POP. In women with concomitant LAM avulsion, mesh repair surgery was associated with a 4-fold reduction in both objective and subjective recurrence of POP. The rate of mesh-related complications was low, and mesh exposure could be treated conservatively or by minor surgery. The benefit of mesh surgery for these high-risk women appears to outweigh the risks of mesh complications, and it could be a treatment option for this group of women. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Cardiac pericytes function as key vasoactive cells to regulate homeostasis and disease

Pericytes (PCs)—mural cells that envelop endothelial cells (ECs) of microvessels—regulate tissue‐specific vasculature development as well as maturation and maintenance of endothelial barrier integrity. However, little is known about their tissue‐specific function in the heart. Specifically, the mechanism by which cardiac PCs constrict coronary capillaries remains undetermined. To gain insights into the function of cardiac PCs at the cellular level, we isolated NG2⁺ PDGFRβ⁺ CD146⁺ CD34⁻ CD31⁻ CD45⁻ PCs for detailed characterization. Functionally, we provide evidence that these PCs increased transepithelial electrical resistance and decreased endothelial permeability. We show for the first time that this population of PCs express contractile proteins, are stimulated by adrenergic signaling, and demonstrate stereotypical contraction and relaxation. Furthermore, we also studied for the first time, the PCs in in vitro models of disease. PCs in hypoxia activated the hypoxia‐inducible factor 1 alpha pathway, increased secretion of angiogenic factors, and caused cellular apoptosis. Supraphysiological levels of low‐density lipoprotein decreased PC proliferation and induced lipid droplet accumulation. Elevated glucose levels triggered a proinflammatory response. Taken together, our study characterizes cardiac PCs under in vitro disease conditions and supports the hypothesis that cardiac PCs are key vasoactive cells that can regulate blood flow in the heart.

Prevalence of obstetric anal sphincter injury following vaginal delivery in primiparous women: a retrospective analysis

INTRODUCTION

Obstetric anal sphincter injuries (OASIS) may be underdetected in primiparous women. This study evaluated the prevalence of OASIS in primiparous women after normal vaginal delivery or instrumental delivery using endoanal ultrasound (US) during postnatal follow-up.

METHODS

This study retrospectively analysed endoanal US data collected during postnatal follow-up (6-12 months after vaginal delivery) at a tertiary hospital in Hong Kong. Offline analysis to determine the prevalence of OASIS was performed by two researchers who were blinded to the clinical diagnosis. Symptoms of faecal and flatal incontinence were assessed with the Pelvic Floor Distress Inventory.

RESULTS

Of 542 women included in the study, 205 had normal vaginal delivery and 337 had instrumental delivery. The prevalence of OASIS detected by endoanal US was 7.8% (95% confidence interval [CI]=4.1%-11.5%) in the normal vaginal delivery group and 5.6% (95% CI=3.1%-8.1%) in the instrumental delivery group. Overall, 82.9% of women with OASIS on endoanal US did not show clinical signs of OASIS. Birth weight was significantly higher in the OASIS group (P=0.012). At 6 to 12 months after delivery, 5.5% of women reported faecal incontinence and 17.9% reported flatal incontinence, but OASIS was not associated with these symptoms.

CONCLUSIONS

Additional training for midwives and doctors may improve OASIS detection.

Pericytes in the Heart

Mural cells known as pericytes envelop the endothelial layer of microvessels throughout the body and have been described to have tissue-specific functions. Cardiac pericytes are abundantly found in the heart, but they are relatively understudied. Currently, their importance is emerging in cardiovascular homeostasis and dysfunction due to their pleiotropism. They are known to play key roles in vascular tone and vascular integrity as well as angiogenesis. However, their dysfunctional presence and/or absence is critical in the mechanisms that lead to cardiac pathologies such as myocardial infarction, fibrosis, and thrombosis. Moreover, they are targeted as a therapeutic potential due to their mesenchymal properties that could allow them to repair and regenerate a damaged heart. They are also sought after as a cell-based therapy based on their healing potential in preclinical studies of animal models of myocardial infarction. Therefore, recognizing the importance of cardiac pericytes and understanding their biology will lead to new therapeutic concepts.

Reduced cognitive function, increased blood-brain-barrier transport and inflammatory responses, and altered brain metabolites in LDLr -/-and C57BL/6 mice fed a western diet

Recent work suggests that diet affects brain metabolism thereby impacting cognitive function. Our objective was to determine if a western diet altered brain metabolism, increased blood-brain barrier (BBB) transport and inflammation, and induced cognitive impairment in C57BL/6 (WT) mice and low-density lipoprotein receptor null (LDLr -/-) mice, a model of hyperlipidemia and cognitive decline. We show that a western diet and LDLr -/- moderately influence cognitive processes as assessed by Y-maze and radial arm water maze. Also, western diet significantly increased BBB transport, as well as microvessel factor VIII in LDLr -/- and microglia IBA1 staining in WT, both indicators of activation and neuroinflammation. Interestingly, LDLr -/- mice had a significant increase in ¹⁸F- fluorodeoxyglucose uptake irrespective of diet and brain ¹H-magnetic resonance spectroscopy showed increased lactate and lipid moieties. Metabolic assessments of whole mouse brain by GC/MS and LC/MS/MS showed that a western diet altered brain TCA cycle and β-oxidation intermediates, levels of amino acids, and complex lipid levels and elevated proinflammatory lipid mediators. Our study reveals that the western diet has multiple impacts on brain metabolism, physiology, and altered cognitive function that likely manifest via multiple cellular pathways.

Longitudinal pelvic floor biometry: which factors affect it?

OBJECTIVES

To evaluate pelvic floor biometry of women 3-5 years after their first delivery. The effect of a subsequent delivery and the mode of delivery on pelvic floor biometry were also studied.

METHODS

Three-hundred and twenty-eight women who had been examined by translabial ultrasound during their first singleton pregnancy and at 8 weeks and 1 year postpartum, were invited for a follow-up 3-5 years later. The positions of the bladder neck, cervix, anorectal junction and hiatal area (HA) were evaluated using translabial ultrasound. The effects of parity, mode of delivery and levator ani muscle avulsion were studied.

RESULTS

A total of 240 women completed the study. Of these, 179 had one or more vaginal deliveries (VD) (VD-only group), 52 had one or more Cesarean sections (CS) (CS-only group) and nine had both VD and CS at follow-up. The mean interval between the first delivery and follow-up was 3.8 years. A significantly lower bladder neck and anorectal junction on Valsalva, a lower cervix at rest, on Valsalva and pelvic floor muscle contraction, and a greater HA were observed in the VD-only group at follow-up, compared with findings at 1 year of follow-up or in the first pregnancy. The findings were similar in the CS-only group, except without a lower anorectal junction on Valsalva. Compared with the primiparous VD-only group, a greater HA at rest was observed in the multiparous VD-only group (P = 0.027). The VD-only group had a greater HA than the CS-only group.

CONCLUSIONS

At 3-5 years after first delivery, a lower bladder neck, cervix and anorectal junction, and a greater HA were observed compared with findings in the first trimester and at 1 year of follow-up, regardless of parity or mode of delivery. Women with two or more VDs had a greater HA compared with those who had only one VD, and women with at least one VD had a greater HA compared with those who delivered by CS only. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Levator ani muscle avulsion is a risk factor for expulsion within 1 year of vaginal pessary placed for pelvic organ prolapse

OBJECTIVE

The aim of this study was to investigate whether the presence of levator ani muscle (LAM) avulsion is associated with expulsion within 1 year of a vaginal pessary placed for pelvic organ prolapse (POP).

METHODS

This was a prospective observational study of consecutive women with symptomatic POP, who had not received treatment for the condition before the consultation and opted for vaginal pessary placement in our center. Volume acquisition was performed before pessary insertion and offline analysis of the 3D/4D transperineal ultrasound volume data was performed. LAM was assessed on maximum pelvic floor muscle contraction (PFMC) and hiatal dimensions were assessed at rest, on PFMC and on maximum Valsalva. Results were compared between women in whom the pessary was retained for 1 year and those in whom the pessary was expelled within 1 year.

RESULTS

The datasets of 255 women were analyzed including 147 (57.6%) women who had a vaginal pessary continuously in place over 1 year and 108 (42.4%) with pessary expulsion. Mean age was 63.2 (SD, 9.9) years and median parity was 3 (2-4). Eighteen (7.1%) had Stage I, 164 (64.3%) Stage II, 67 (26.3%) Stage III and six (2.4%) Stage IV POP. Women with vaginal pessary expulsion within 1 year had significantly larger hiatal dimensions at rest and on Valsalva, larger hiatal area during rest, PFMC and Valsalva and higher rate of LAM avulsion (53.7% vs 27.2%, P < 0.01) compared with women in whom the pessary was retained for 1 year. After controlling for potential confounders, LAM avulsion remained a risk factor (OR, 3.18, P < 0.01) of vaginal pessary expulsion within 1 year.

CONCLUSIONS

Women in whom a vaginal pessary was expelled within 1 year of placement for POP had a larger hiatus. Presence of LAM avulsion was associated with a three-fold increase in the risk of expulsion of a vaginal pessary within 1 year. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Longitudinal follow-up of levator ani muscle avulsion: does a second delivery affect it?

OBJECTIVES

To evaluate the morphological outcome of levator ani muscle (LAM) avulsion 3-5 years after a first delivery and to assess the effect of a second delivery on this condition. The impact of LAM avulsion on pelvic floor disorders was also studied.

METHODS

Six hundred and sixty-six women who had been assessed for LAM avulsion 8 weeks after their first delivery were invited for a follow-up examination 3-5 years later. Women completed the Pelvic Floor Distress Inventory including the Urinary Distress Inventory (UDI) and Pelvic Organ Prolapse Distress Inventory (POPDI) questionnaires to explore symptoms of pelvic floor disorders, and the pelvic floor was examined using three-dimensional translabial ultrasound and assessed using the pelvic organ prolapse quantification system.

RESULTS

Three hundred and ninety-nine women completed the study, of whom 151 were multiparous. Mean interval between first delivery and follow-up was 42.3 ± 7.6 months. Among 69 women who had LAM avulsion 8 weeks after their first delivery, nine (13.0%) had no LAM avulsion at follow-up. One (0.9%) woman had a new LAM avulsion after her second vaginal delivery. A greater proportion of women with LAM avulsion reported symptoms of stress urinary incontinence (SUI) (adjusted odds ratio, 2.09 (95% CI, 1.18-3.70); P = 0.01) and symptoms of prolapse than did women without avulsion; however, this difference did not reach statistical significance (P = 0.61). Women with LAM avulsion had higher UDI and POPDI scores than did women without avulsion (median UDI score, 17.7 (interquartile range (IQR), 5.0-32.4) vs 9.2 (IQR, 0.0-22.1); P = 0.045 and median POPDI score, 20.8 (IQR, 8.8-40.5) vs 10.7 (IQR, 0.0-32.8); P = 0.021).

CONCLUSIONS

The risk of developing new LAM avulsion after a second vaginal delivery is low (0.9%). Healing of LAM avulsion was observed in 13% of women who had at least one vaginal delivery. At 3-5 years after delivery, women with LAM avulsion reported symptoms of SUI more often than did those without, and had higher UDI and POPDI scores, implying more bothersome symptoms. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Triglyceride-rich lipoprotein lipolysis products increase blood-brain barrier transfer coefficient and induce astrocyte lipid droplets and cell stress

Elevation of blood triglycerides, primarily as triglyceride-rich lipoproteins (TGRL), has been linked to cerebrovascular inflammation, vascular dementia, and Alzheimer's disease (AD). Brain microvascular endothelial cells and astrocytes, two cell components of the neurovascular unit, participate in controlling blood-brain barrier (BBB) permeability and regulating neurovascular unit homeostasis. Our studies showed that infusion of high physiological concentrations of TGRL lipolysis products (TGRL + lipoprotein lipase) activate and injure brain endothelial cells and transiently increase the BBB transfer coefficient (K_i = permeability × surface area/volume) in vivo. However, little is known about how blood lipids affect astrocyte lipid accumulation and inflammation. To address this, we first demonstrated TGRL lipolysis products increased lipid droplet formation in cultured normal human astrocytes. We then evaluated the transcriptional pathways activated in astrocytes by TGRL lipolysis products and found upregulated stress and inflammatory-related genes including activating transcription factor 3 (ATF3), macrophage inflammatory protein-3α (MIP-3α), growth differentiation factor-15 (GDF15), and prostaglandin-endoperoxide synthase 2 (COX2). TGRL lipolysis products also activated the JNK/cJUN/ATF3 pathway, induced endoplasmic reticulum stress protein C/EBP homologous protein (CHOP), and the NF-κB pathway, while increasing secretion of MIP-3α, GDF15, and IL-8. Thus our results demonstrate TGRL lipolysis products increase the BBB transfer coefficient (K_i), induce astrocyte lipid droplet formation, activate cell stress pathways, and induce secretion of inflammatory cytokines. Our observations are consistent with evidence for lipid-induced neurovascular injury and inflammation, and we, therefore, speculate that lipid-induced astrocyte injury could play a role in cognitive decline.

Antenatal pelvic floor biometry is related to levator ani muscle injury

OBJECTIVE

To evaluate the relationship between antenatal pelvic floor biometry and levator ani muscle (LAM) injury in Chinese women.

METHODS

Three-dimensional transperineal ultrasound was performed in nulliparous Chinese women with a singleton pregnancy at 9-12 weeks, 26-28 weeks and 36-38 weeks of gestation and again at 12 months after delivery. Hiatal anteroposterior (AP) diameter, transverse diameter and area were measured on the antenatal ultrasound volumes obtained at rest, on Valsalva maneuver and during pelvic floor muscle contraction (PFMC). LAM injury was evaluated using ultrasound volumes obtained during PFMC at 12 months after delivery.

RESULTS

In total, 328 women completed the study. At 12 months after delivery, 38 (14.8% of those who delivered vaginally) women had LAM injury; 28 were unilateral (14 right- and 14 left-sided) and 10 were bilateral. In all three trimesters there was smaller hiatal AP diameter and hiatal area in women with LAM injury when compared with women without injury. On multivariable analysis of the three factors, hiatal AP diameter at rest, hiatal area at rest and operative vaginal delivery, only hiatal AP diameter at rest in all three trimesters was an independent factor of LAM injury. A larger hiatal AP diameter at rest in the first, second and third trimesters reduced the likelihood of LAM injury with odds ratios of 0.21, 0.15 and 0.21, respectively.

CONCLUSIONS

A smaller antenatal hiatal AP diameter at rest is a risk factor for LAM injury. The hiatal AP diameter is relatively simple to measure and the error in measurement is relatively small. A prospective study to confirm this relationship and to explore whether this measurement, performed in the midsagittal plane, is repeatable should be performed. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

Abstract P4-14-10: Pertuzumab overcomes chemotherapy/trastuzumab resistance in ER+/Her2+ tumors classified as luminal functional subtype by the 80-gene BluePrint assay in the prospective neo-adjuvant breast registry symphony trial (NBRST)

Background

The prospective Neo-adjuvant Breast Registry Symphony Trial (NBRST) enrolled over 1000 US patients between June 2011 and December 2014. The aim of NBRST study is to compare chemosensitivity as defined by pathological Complete Response (pCR) using the 80-gene BluePrint functional subtype profile vs. conventional IHC/FISH subtyping. Treatment was at the discretion of the physician utilizing standard NCCN regimens. Pertuzumab, a monoclonal antibody, inhibits the dimerization of HER2 with other HER receptors. Pertuzumab received US FDA approval for the neo-adjuvant treatment of HER2-positive breast cancer in September 2013. Essentially all patients with HER2 positive cancers were treated with chemotherapy + trastuzumab and after this date pertuzumab was added, creating 2 distinct groups of Her2 treated patients.

The aim of the current analysis is to compare the pCR rate of trastuzumab (H) vs trastuzumab and pertuzumab (H + P) by conventional and BluePrint functional subtype.

Methods

The current analysis includes women from the NBRST study, with histologically proven breast cancer, who received neo-adjuvant chemotherapy plus H or H + P and who provided written informed consent. Pathological assessment of Her2 was done according to ASCO CAP guidelines at the time of diagnosis. BluePrint (BP) classifies patients into Luminal, HER2 or Basal-type. pCR is defined as T0/isN0. All pCRs were verified with a de-identified copy of the surgical pathology report. Fisher's exact test was used to compare pCR rates within different subgroups.

Results

252 IHC/FISH Her2+ patients received H (166) or H + P (86). The median age was 53 (range 23-81). 8% was stage I, 68% stage II and 24% stage III. 65% were ER positive.

BP classified 55% of patients as HER2, 32% as Luminal, and 14% as Basal-type.

The pCR rates and p-values within different subgroups of clinical Her2+ patients are provided in the table below.

pCR rates and p-values within different subgroups of clinical Her2+ patients(n)H (pCR rate)H + P (pCR rate)p-valueTotal (n=252)40%59%0.005IHC/FISH Her2+/ER+ (163)30%57%0.001IHC/FISH Her2+/ER- (89)69%63%0.82BP HER2 (138)57%78%0.01BP Luminal (80)4%38%0.0002BP Basal (34)47%38%0.69

Conclusions

Addition of pertuzumab to trastuzumab significantly increased response rate in ER+/Her2+, BP HER2 and BP Luminal patients but not in ER-negative and BP Basal patients.

Pertuzumab overcame resistance to NCT/trastuzumab in a substantial proportion of the IHC/FISH Her2+/BP Luminal subgroup; indicated by a significantly increased pCR rate.

Citation Format: Peter B, Pat W, Paul B, Jennifer B, Pellicane JV, Murray MK, Dul CL, Mislowsky AM, Nash CH, Richards PD, Lee LL, Stork-Sloots L, de Snoo F, Untch S, Gittleman M, Akbari S, Rotkis MC. Pertuzumab overcomes chemotherapy/trastuzumab resistance in ER+/Her2+ tumors classified as luminal functional subtype by the 80-gene BluePrint assay in the prospective neo-adjuvant breast registry symphony trial (NBRST). [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-14-10.

Pelvic floor biometry in Chinese primiparous women 1 year after delivery: a prospective observational study

OBJECTIVES

To evaluate pelvic floor biometry in Chinese women 1 year following childbirth and to explore factors that affect it.

METHODS

Translabial ultrasound examination was performed at rest, on Valsalva maneuver (VM) and on pelvic floor muscle contraction (PFMC) in the first, second and third trimesters of pregnancy and at 8 weeks, 6 months and 12 months after delivery in a cohort of women delivering at term their first child. Offline analysis was undertaken to measure the position of the bladder neck, cervix, anorectal junction and hiatal dimensions at each posture and at each visit, and to detect levator ani muscle (LAM) injury on PFMC 8 weeks and 12 months after delivery. Results were analyzed according to mode of delivery.

RESULTS

We recruited 442 women, of whom 328 (74.2%) completed the study; there was LAM injury in 48 women at 8 weeks and in only 38 women at 12 months. When comparing first-trimester biometry to that at 12 months after delivery, the bladder neck was more distal on VM and bladder neck displacement was increased, and the cervix was lower at rest and on VM in the vaginal delivery group. In the Cesarean section group, bladder neck and anorectal junction were more distal on VM, the cervix was lower at rest, on VM and on PFMC, and the hiatal area was increased on VM. There was a greater increase in hiatal area after vaginal delivery. Overall, 34.8% had irreversible hiatal distension (> 20% increase in hiatal area after delivery as compared to first trimester). LAM injury was significantly associated with irreversible hiatal distension (odds ratios, 5.2-9.5 at different postures).

CONCLUSIONS

Pregnancy beyond 35 weeks of gestation has an effect on the pelvic floor of Chinese women, irrespective of mode of delivery. The pelvic organs remain more mobile after delivery when compared to in the first trimester, and there is no clear difference between the findings observed following vaginal delivery or Cesarean section, except in hiatal distension, which is greater after vaginal delivery. LAM injury is the factor most strongly associated with irreversible hiatal distension.

Health promotion board-ministry of health clinical practice guidelines: treating tobacco use and dependence

The Health Promotion Board (HPB) has updated the clinical practice guidelines on Treating Tobacco Use and Dependence to provide health professionals in Singapore with evidence-based interventions for smoking cessation. This article reproduces the introduction and executive summary of key guideline recommendations (with recommendations from the guidelines) from the HPB-MOH Clinical Practice Guidelines on Treating Tobacco Use and Dependence, for the information of SMJ readers. Chapters and page numbers mentioned in the reproduced extract refer to the full text of the guidelines, which are available from the Health Promotion Board website: http://www.hpb.gov.sg/cpg-smoking-cessation. The recommendations should be used with reference to the full text of the guidelines. Following this article are multiple choice questions based on the full text of the guidelines.

Pelvic floor biometry during a first singleton pregnancy and the relationship with symptoms of pelvic floor disorders: a prospective observational study

OBJECTIVE

To assess pelvic floor biometry during pregnancy and the correlation with symptoms of pelvic floor disorders in women.

DESIGN

A prospective observational study.

SETTING

Antenatal clinic between August 2009 and May 2011.

POPULATION

Nulliparous women in their first pregnancy.

METHODS

Pelvic floor was assessed by translabial ultrasound and symptoms of pelvic floor disorders were explored with a standardised questionnaire at each trimester.

MAIN OUTCOME MEASURES

Pelvic floor biometry during pregnancy.

RESULTS

A total of 405 (91.6%) women completed the study. As the pregnancy advanced, there was significant descent of the bladder neck (BN), cervix, and anorectal junction. The hiatal area (HA) was significantly enlarged, with a mean increase of 15.1 ± 24.8% at rest, and 24.7 ± 28.5% at Valsalva, at third trimester when compared with first trimester. Risk factors for stress urinary incontinence (SUI) were: descent of BN at Valsalva (OR 3.2, 95% CI 1.2-8.5), increase in HA at pelvic floor contraction (PFMC; OR 1.3, 95% CI 1.0-1.6), and increase in maternal age (OR 1.1, 95% CI 1.0-1.2), at first trimester; increase in HA at PFMC (OR 1.3, 95% CI 1.1-1.5) at second trimester; and descent of BN at rest (OR 2.3, 95% CI 1.1-4.9) and increase in maternal age (OR 1.1, 95% CI 1.02-1.2) at third trimester. Descent of anorectal junction (OR 1.5, 95% CI 1.1-1.9) and increase in HA at rest (OR 1.2, 95% CI 1.0-1.3) were factors for prolapse symptoms at second and third trimester, respectively.

CONCLUSIONS

Pelvic floor changes begin during pregnancy. There was significant descent of the BN, cervix, and anorectal junction, and enlargement of the hiatal area, as the pregnancy advanced. SUI was associated with descent of the BN, and prolapse symptoms were associated with an increase in the hiatal area.

Prevalence of urinary and fecal incontinence in Chinese women during and after their first pregnancy

INTRODUCTION AND HYPOTHESIS

This study evaluated factors and their prevalence associated with urinary (UI) and fecal (FI) incontinence during and after a woman's first pregnancy.

METHODS

Nulliparous Chinese women with no UI or FI before pregnancy were studied with a standardized questionnaire for UI and FI from early pregnancy until 12 months after childbirth. Maternal characteristics and obstetric data were analyzed using descriptive analysis, independent sample t test, chi-square test, and logistic regression.

RESULTS

Three hundred and twenty-eight (74.2 %) women completed the study. The prevalence of antenatal UI increased with gestation. Overall, 192 (58.5 %), 60 (18.3 %), and 76 (23.1 %) had normal vaginal delivery, instrumental delivery, and cesarean section, respectively. Twelve months after delivery, prevalence of stress urinary incontinence (SUI) and urge urinary incontinence (UUI) was 25.9 % [95 % confidence interval (CI) 21.5-30.6] and 8.2 % (95 % CI 5.2-11.2), respectively. In those who delivered vaginally, the prevalence was 29.7 % and 9.1 %, respectively. Prevalence of FI was 4.0 % (95 % CI 1.9-6.1). On logistic regression, vaginal delivery [odds ratio (OR) 3.6], antenatal SUI (OR 2.8), and UUI (OR 2.4) were associated with SUI. Antenatal UUI (OR 6.4) and increasing maternal body mass index (BMI) at the first trimester (OR 1.2) were associated with UUI. Antenatal FI was associated with FI (OR 6.1).

CONCLUSIONS

The prevalence of SUI, UUI, and FI were 25.9 %, 8.2 %, and 4.0 %, respectively, 12 months after delivery. Vaginal delivery, antenatal SUI, and UUI were associated with SUI; antenatal UUI and increasing maternal BMI at the first trimester were associated with UUI. Antenatal FI was associated with FI. Pregnancy, regardless of route of delivery and obstetric practice, had an effect on UI and FI.

Case-control study of risk factors for breast cancer in Nigerian women: a pilot study

OBJECTIVE

To evaluate the risk factors for breast cancer among women in Midwestern and Southeastern Nigeria.

DESIGN

A case control study.

SETTING

University of Benin Teaching hospital, Benin City and University of Port Harcourt Teaching Hospital, Port Harcourt in Nigeria.

SUBJECTS

Fifty one women with diagnosis of breast cancer and their age- and sex matched controls were included in the study.

INTERVENTIONS

Data was collected during a 30 minute period after obtaining written informed consent using interviewer-administered questionnaires.

RESULTS

Parity > 4 (OR = 0.50, 95% Cl 0.17, 1.46) and duration of breast feeding > 60 months (OR = 0.58, 95% Cl 0.23, 1.48) were associated with reduced risk of breast cancer while birth order > 3 (OR = I.50, 95% Cl 0.25, 8.98), age at first full term pregnancy>20 years (OR = 2.50, 95% Cl 0.78, 7.97) and longer duration of reproductive period (OR = 1.25, 95% Cl 0.34, 4.66) were associated with increased risk of breast cancer.

CONCLUSION

The study has shown that high parity and long duration of breastfeeding are associated with reduced risk while high birth order and late age at first full-term pregnancy are associated with increased risk of breast cancer.

Replica Ornstein-Zernike self-consistent theory for mixtures in random pores

We present a self-consistent integral equation theory for a binary liquid in equilibrium with a disordered medium, based on the formalism of the replica Ornstein-Zernike (ROZ) equations. Specifically, we derive direct formulas for the chemical potentials and the zero-separation theorems (the latter provide a connection between the chemical potentials and the fluid cavity distribution functions). Next we solve a modified-Verlet closure to ROZ equations, which has built-in parameters that can be adjusted to satisfy the zero-separation theorems. The degree of thermodynamic consistency of the theory is also kept under control. We model the binary fluid in random pores as a symmetrical binary mixture of nonadditive hard spheres in a disordered hard-sphere matrix and consider two different values of the nonadditivity parameter and of the quenched matrix packing fraction, at different mixture concentrations. We compare the theoretical structural properties as obtained through the present approach with Percus-Yevick and Martinov-Sarkisov integral equation theories, and assess both structural and thermodynamic properties by performing canonical standard and biased grand canonical Monte Carlo simulations. Our theory appears superior to the other integral equation schemes here examined and provides reliable estimates of the chemical potentials. This feature should be useful in studying the fluid phase behavior of model adsorbates in random pores in general.

Polycyclic aromatic hydrocarbons present in cigarette smoke cause bone loss in an ovariectomized rat model

A number of epidemiological studies have suggested that cigarette smoking is a risk factor for osteoporosis. Benzo(a)pyrene (BaP) and 7,12-dimethylbenz(a)anthracene (DMBA) are polycyclic aromatic hydrocarbons (PAHs) found in the tar fraction of cigarette smoke, as well as in car exhaust and furnace gases. We hypothesized that BaP and DMBA are responsible, through interaction with the aryl hydrocarbon receptor (AhR), for the bone loss and fragility seen in smoking-related osteoporosis. In this study four groups of 9-month-old Sprague-Dawley rats were examined. An intact group served as controls. A second control was the ovariectomized (ovx) group. The third group (ovx + E(2)) were ovariectomized and also given a continuous basal dose of estrogen by implanted estrogen pellet (0.085 mg of 17beta-estradiol per rat). The fourth group (ovx + E(2) + BaP/DMBA) was ovariectomized with an estradiol pellet, and received subcutaneous injections of 250 microg/kg of BaP/DMBA weekly for 15 weeks. The loss of ovarian function allowed the study of a direct effect of BaP/DMBA on bone while the concomitant estrogen repletion prevented ovx-related bone loss. Dual-energy X-ray absorptiometry (DEXA), histomorphometry, image analysis, and mechanical testing were used to determine the effect of the treatments on bone. The DEXA results showed a significant (p < 0.05) decrease in bone mineral density compared with intact controls with both ovx alone and with ovx + E(2) + BaP/DMBA treatment. The ovx + E(2) rats were similar to the intact controls. The osteoid parameters showed a significant increase (p < 0.05) with BaP/DMBA addition vs. intact controls, mimicking the ovx rats. The ovx + E(2) rats had osteoid parameters comparable to those of intact rats. Bone connectivity was decreased in the ovx and ovx + E(2) + BaP/DMBA animals. Connectivity of the ovx + E(2) rats was comparable to that of intact animals. A decrease in failure force was seen in three-point bending for the ovx + E(2) + BaP/DMBA group and in vertebral compression in both the ovx and ovx + E(2) + BaP/DMBA groups vs. intact controls. The mechanical properties of the ovx + E(2) rats were similar to those of intact rats. These results demonstrate that BaP/DMBA causes a loss of bone mass and bone strength, possibly through an increase in bone turnover. This is the first in vivo study linking environmental toxicants, found in the tar fraction of cigarette smoke and in urban air pollution, to loss of bone mass and strength in estrogen-replete ovx rats.

The health status of rural and urban ambulatory elderly in Taipei County

BACKGROUND

To study the differences in the health status of rural and urban ambulatory elderly in Taipei County.

METHOD

Non-compulsory general health check-up for elderly people over 65 years old in rural and urban areas. The content of the health examination included past medical history, health behavior, physical examination, laboratory examination, electrocardiogram and x-ray. Chi square test, t-test and logistic regression were applied for analysis. Risk factors relating to the cardiovascular system were included in the study. Gender differences affecting the prevalence of diseases and health behavior were also considered in the analysis.

RESULTS

Significantly higher proportions of the rural elderly men smoked, drank alcohol, and had hypertension and impaired renal function. On the other hand, higher proportions of rural elderly women were obese and had diabetes, hypertension and renal impairment. The mean plasma glucose level of newly-diagnosed diabetic patients in the rural area was significantly higher than that in the urban area (p < 0.05). Diabetes, obesity, hypercholesterolemia and smoking were significantly associated with hypertension. The odds ratio for hypertension between rural and urban areas was 1.45 (p < 0.0001). The cardiovascular risk-rating score of rural elderly was statistically higher than that of urban elderly (p < 0.001).

CONCLUSION

There were some minor differences in health status between urban and rural elderly. Health promotion should be varied according to the needs of various communities and various risk groups. Further studies should concentrate on prospective cohort research with well-defined determinants to evaluate whether cost-effective biopsychosocial intervention is necessary.

The influence of professional commitment on turnover intention

This study investigated the influence of professional commitment on turnover intentions of nurses. The study also examined the relationships between demographic data, work-related variables and the professional commitment. The self-administered questionnaires were distributed to one fifth of Southern Taiwan's population of nurses (n = 4,000). A total of 2,543 subjects completed the questionnaires with a 63.6% response rate. The nurses exhibited a medium-high degree of overall professional commitment. Age, salary, years in profession and years in organization were correlated significantly with professional commitment by Pearson's correlation. There were significant correlations between professional commitment and marital status, educational level, status of the youngest child, level of position, and family support in Spearman's correlations. Family support, age, level of position and status of hospital were the significant predictors in the final regression analysis model. The discriminant analysis showed that 45.4% of nursing professional commitment was correctly classified in predicting intention to leave the profession and 33.1% in predicting the intention to leave the organization. The study recommended that nursing professional commitment is an important moderator to affect the turnover intention of staff nurses.

Expression of mutant amyloid precursor proteins decreases adhesion and delays differentiation of Hep-1 cells

The amyloid precursor protein (APP) is a type I integral membrane protein and is processed to generate several intra-cellular and secreted fragments. The physiological role of APP and its processed fragments is unclear. Several mutations have been discovered in APP, which are causative of early-onset, familial, neurological disease, including Alzheimer's disease (FAD). These mutations alter the processing of APP and lead to excess production and extra-cellular deposition of A-beta peptide (Abeta). We have examined the role of APP in a cell culture model of endothelial cell function. The endothelial cell line, Hep-1, was stably transfected with wild-type (wt) and FAD mutant forms of APP (mAPP). Secretion of sAPPalpha was reduced in cell lines over-expressing mAPP when these cells were grown on several different substrates. Levels of secreted Abeta were increased as measured by ELISA in the mutant cell lines. Cell adhesion to laminin-, fibronectin-, collagen I-, and collagen IV-coated culture flasks was reduced in all mAPP-expressing cell lines, while in lines over-expressing wt-APP, adhesiveness was slightly increased. Cell lines over-expressing mAPP differentiated more slowly into capillary network-like structures on Matrigel than those expressing wt-APP. No differences were detected among all cell lines in a migration/invasion assay. The results suggest that APP may have a role in cell adhesiveness and maturation of endothelial cells into capillary-like networks. The reduction in adhesion and differentiation in mutant cell lines may be due to reduced amounts of sAPPalpha released into the culture media or toxic effects of increased extracellular Abeta.

Automated static perimetry: the influence of myopia and its method of correction

OBJECTIVE

To determine how the magnitude of myopia and its method of correction influence visual field testing.

DESIGN

Prospective observational case series, including comparison of spectacles and contact lenses.

PARTICIPANTS

One hundred forty-six ophthalmologically normal males 19 to 24 years of age with myopia (spherical equivalent from -0.50 to -14.0 diopters).

METHODS

Participants performed automated static threshold perimetry. Refractive errors were corrected using trial lenses and soft contact lenses. Subjects were tested with both methods of correction, the order of which was randomized.

MAIN OUTCOME MEASURES

Threshold sensitivity and global indexes.

RESULTS

Only one subject (0.7%) had a significant reproducible visual field defect on both methods of correction. Six subjects (4.1%) had a focal visual field defect on one method of correction but not the other. For myopia greater than -4.0 diopters, the mean defect decreased significantly as axial length and degree of myopia increased (P: < 0.01). Similar results were obtained with either method of correction.

CONCLUSIONS

Threshold sensitivity is reduced in moderate and high myopia, regardless of the method of correction. The surprisingly low prevalence of visual field defects in this myopic population disputes the widely held view that myopia is associated commonly with visual field abnormalities. If field defects are found in myopes on automated perimetry, it is advisable to repeat the test with another method of optical correction to check that such defects are genuine and not related to the method of refractive correction.

Effect of Soil Depth and Moisture on the Vertical Distribution of Steinernema riobrave (Nematoda: Steinernematidae)

The effect of soil moisture on the distribution of Steinernema riobrave in a sand column was determined. Larvae of Pectinophora gossypiella were used to detect S. riobrave infective juveniles (IJ) in each 2.5-cm section of 30-cm-long soil columns. Soil moisture was determined for each section and related to the numbers of nematodes recovered from infected insect baits. Infective juveniles of S. riobrave applied on the sand column surface showed some degree of positive geotaxis. IJ in soil columns with a consistent moisture gradient grouped in the upper 12.7 cm within a water potential range of 40 to 0.0055 MPa (2% to 14% moisture). Nematodes in sand columns that were gradually dehydrating moved down the soil column, aggregating on the 28th day between 15-23 cm in depth. Nematode redistribution over time allowed IJ to remain within a water potential range of 0.1 to 0.012 MPa (5.2% to 9.5% moisture).

ICP monitoring in the rat: comparison of monitoring in the ventricle, brain parenchyma, and cisterna magna

Various methods of continuous intracranial pressure (ICP) monitoring during experimental procedures in the rat have been described. However, no systematic comparison of ICP monitoring in the ventricle, brain parenchyma, and cisterna magna has been reported. Since accurate and reliable ICP measurements are important in experimental models of traumatic brain injury, the present study was conducted to compare simultaneous ICP measurements from ventricular, cisterna magna, and intraparenchymal monitors during ICP changes. Subdural hematoma was produced by infusion of 0.3 ml of autologous blood into the subdural space over 6 min. The ventricular and the intraparenchymal fiberoptic catheter produced reliable and comparable pressure recordings, that did not statistically differ (p = 0.4), throughout the one hour monitoring time. In contrast, the cisterna magna catheter was less reliable and produced significantly lower readings throughout the monitoring time (p<0.001). The intraparenchymal device produced greater cortical damage than the ventricular catheter. In conclusion, ventricular ICP monitoring is the preferred method under these circumstances, since it is accurate and induces least brain damage.

Post mass-immunization measles outbreak in Taoyuan County, Taiwan: dynamics of transmission, vaccine effectiveness, and herd immunity

OBJECTIVES

Analysis of national surveillance data and a seroepidemiologic investigation were conducted to elucidate the causes and epidemiologic characteristics of a measles outbreak in Taoyuan, Taiwan, 1994.

METHODS

Measles cases were identified through a national surveillance system. Reported cases and their physician or school nurses were interviewed to trace additional suspect cases and were sampled for serologic diagnosis. Measles-specific IgG and IgM were assayed. A confirmed case was defined as being positive for measles IgM test but not having received measles vaccination within the previous 3 months.

RESULTS

The outbreak began in Taoyuan City in December 1993 and continued to spread in primary schools and kindergartens, but caused only sporadic cases in neighboring towns. Among 42 confirmed cases, 15 (38%) were primary school children and 16 (38%) were kindergarten children. Among 24 confirmed cases with a vaccination record, 7 had one dose of vaccination, 4 had two doses of vaccination, and 13 (54%) were unvaccinated. The overall measles susceptible proportion at a kindergarten before the outbreak was 8.1% (17/209) and the overall measles cumulative incidence among susceptibles was 0.65 (11/17).

CONCLUSIONS

A measles vaccination coverage of 82% with the first dose at 9 months of age and 63% with the second dose (measles, mumps, and rubella) at 15 months was inadequate to block measles virus circulation in Taoyuan City in 1994. The city center, with a growing population, represents a high risk as an epicenter for measles outbreaks. Measles outbreaks may occur in a school population with 92% herd immunity.

High-performance liquid chromatographic method for the determination of an HIV-1 non-nucleoside reverse transcriptase inhibitor (L-696,229) in plasma samples from animals

A sensitive high-performance liquid chromatographic (HPLC) method was developed and validated to separate and quantitate the levels of L-696,229 (I), a novel human immunodeficiency virus type I non-nucleoside reverse transcriptase inhibitor, and its hydroxy metabolites (II and III) in plasma samples. The procedure involves the addition of a constant known quantity of internal standard to the biological specimen followed by extraction of the compounds of interest into methyl tert.-butyl ether. The organic phase is evaporated to dryness under a gentle stream of nitrogen. The residue is then dissolved in methanol and water and injected onto a reversed-phase HPLC column. A gradient HPLC method is used to elute the compounds which are monitored using UV detection at 319 nm. Absolute calibration factors (from the standard curve) were calculated by analyzing standards, and these factors were used to determine the concentration of drug (I) and its hydroxy metabolites (II and III) in the samples using the internal standard method. The method was linear using a standard concentration range of 50 to 20,000 ng/ml. The limit of quantitation was 50 ng/ml using 200 microliters plasma. The procedure was utilized to monitor plasma levels of I, II and III in acute and chronic toxicity studies in several animal species.

Toxicokinetic analysis of losartan during gestation and lactation in the rat

Previous developmental and reproductive toxicity studies in rats with losartan, a potent AT1-selective angiotensin II (AII) receptor antagonist, correlated maternal treatment during gestation day (GD) 15-20 with irreversible renal abnormalities in the F1 generation (Spence et al., '95a,b). Continued treatment through lactation was also associated with increases in pup mortality and decreases in pup body weights that persisted through weaning. The studies presented here were undertaken to quantify fetal and neonatal exposure to losartan when administered to the dam by oral gavage during early gestation, late gestation, and lactation. Following daily oral dosing of 135 mg/kg/day on GD6-15, fetal drug levels were negligible. However, losartan and its active metabolite, EXP3174 (L-158,641) were readily detectable in fetal plasma on GD 20 (estimated AUC values, 50.70 and 167.70 micrograms/hr/ml, respectively) and maternal milk during lactation (1.61 and 1.67 micrograms/ml, respectively). These studies suggest that the relative increased sensitivity of the fetus as compared to the neonate for losartan-induced renal lesions is related to the degree of exposure which is dependent on the time of administration (early gestation vs. late gestation/lactation) and the route of exposure (transplacental or through the milk). Furthermore, the maximum exposure to losartan and EXP3174 correlates with the ontogeny of the renin angiotensin system on approximately GD 17 and the critical period for losartan-induced renal lesions (GD15-20). The data support the hypothesis that the observed adverse fetal and neonatal effects are pharmacologically mediated, presumably through the lack of AT1 receptor stimulation.

Frequency of human immunodeficiency virus (HIV) infection among contemporary anti-HIV-1 and anti-HIV-1/2 supplemental test-indeterminate blood donors. The Retrovirus Epidemiology Donor Study

BACKGROUND

Follow-up studies from the mid-1980s showed that 1 to 5 percent of blood donors testing reactive in anti-human immunodeficiency virus type 1 (HIV-1) enzyme immunoassay (EIA) and testing indeterminate in Western blot were infected with HIV-1 and were in the process of seroconverting. The present study was conducted to establish the rate of HIV infection among contemporary anti-HIV-1/HIV type 2 (HIV-2) EIA-reactive, Western blot-indeterminate donors.

STUDY DESIGN AND METHODS

Donations (n = 607) with indeterminate HIV supplemental test results were identified by screening 3,021,342 donations given from November 1990 through August 1993 at five participating blood centers. Consenting donors were enrolled and samples taken 4 to 8 weeks after donation. Follow-up sera were tested by EIA and Western blot for anti-HIV-1 seroconversion and by type-specific peptide assays for antibodies to HIV-2 and HIV-1 subtype O. Peripheral blood mononuclear cells and/or plasma from the follow-up samples were tested for HIV-1 DNA and/or RNA by polymerase chain reaction. The rate of HIV-1 infection among Western blot-indeterminate donors was also estimated by multiplying the incidence rate of HIV-1 seroconversion in this donor population by the estimated duration of the EIA-reactive and Western blot-indeterminate window during seroconversion (8.5 days).

RESULTS

Supplemental test-indeterminate donors (n = 355) enrolled a median of 38 days after donation; 265 (75%) of these donors were identified as indeterminate after an anti-HIV-1/2 EIA-reactive donation. Enrolled and non-enrolled donors had similar distributions of demographic characteristics and band patterns. Follow-up samples from all 355 donors tested negative for HIV-1 in polymerase chain reaction. Follow-up sera tested Western blot-negative in 54 cases (15%) and Western blot-indeterminate in 299 (84%). Two follow-up sera (0.6%) were interpreted, according to manufacturer's package insert criteria, as Western blot positive with p24 and gp41 bands and/or gp120/160 bands; however, paired testing of index and follow-up sera from these two cases showed identical Western blot and EIA reactivity, and polymerase chain reaction was negative for HIV RNA and DNA, which ruled out HIV infection. The absence of HIV infection in 355 Western blot-indeterminate donors was consistent with our incidence-based model analysis, which yielded an estimate of one HIV-1 infection for every 215 Western blot-indeterminate donations (95% CI, 1/39-1/8333).

CONCLUSION

Contemporary blood donors classified as indeterminate in supplemental HIV testing are infrequently infected with HIV. Donors whose follow-up samples test negative in anti-HIV-1/2 EIAs and negative or persistently indeterminate in Western blots should be considered eligible for reinstatement.

Time course of detection of viral and serologic markers preceding human immunodeficiency virus type 1 seroconversion: implications for screening of blood and tissue donors

BACKGROUND

Almost all human immunodeficiency virus (HIV) transmission via blood or tissues that has occurred since anti-HIV screening was implemented in 1985 is traceable to blood given after infection but before antibody seroconversion, a time that is referred to as the window period. In this study, the performance of newer assays designed to detect viral and serologic markers soon after infection is assessed, and the reduction in the window period achieved by these assays is estimated.

STUDY DESIGN AND METHODS

Three cohort studies of persons at high risk for acquiring HIV infection were identified. These studies included well-controlled HIV type 1 (HIV-1) polymerase chain reaction (PCR) analyses of serial preseroconversion specimens from HIV-1-seroconverting homosexual men or intravenous drug users. Of 81 enrollees with anti-HIV-1 seroconversion documented by a viral lysate anti-HIV-1 enzyme immunosorbent assay (EIA) available in 1989, 13 (16%) had PCR-positive preseroconversion specimens. In the present study, sera from these 13 PCR-positive samples were further tested for anti-HIV by 10 contemporary EIAs and 6 supplemental assays, as well as being tested for plasma p24 antigen and HIV-1 RNA. Preseroconversion sera from 38 HIV-1 DNA PCR-negative cohort participants were also tested by selected anti-HIV EIAs and tested for p24 antigen and HIV-1 RNA. On the basis of these laboratory data and the intervals between blood drawing in all 81 men, the reduction in the preseroconversion window period achieved by these new assays was estimated with a mathematical model developed to analyze seroconversion data.

RESULTS

Nine (69%) of the 13 preseroconversion PCR-positive samples had anti-HIV that was detectable by one or more contemporary anti-HIV-1 or anti-HIV type 2 EIA. Supplemental antibody assays were negative on all four EIA-nonreactive preseroconversion samples and negative or indeterminate on a high proportion of the nine EIA-reactive PCR-positive samples. Eight (61%) of the 13 samples were p24 antigen-positive, and 11 (85%) were HIV-1 RNA-positive. The estimated reductions in the window period (relative to the index viral lysate-based anti-HIV EIA) were as follows: contemporary anti-HIV-1/2 EIAs, 20.3 days (95% Cl, 8.0-32.5); p24 antigen and DNA PCR, 26.4 days (95% Cl, 12.6-38.7); and RNA PCR, 31.0 days (95% Cl, 16.7-45.3).

CONCLUSION

Recent improvement in the sensitivity of anti-HIV assays has resulted in significant shortening of the preseroconversion window period. Consequently, the incremental reduction in the window period that could be achieved by implementing direct virus-detection assays has diminished significantly.

Changes in the patterns of initiation of cigarette smoking in the United States: 1950, 1965, and 1980

We examined changes in the patterns of the rates of smoking initiation in the United States by gender for 1950, 1965, and 1980. Data from National Health Interview Surveys on the ages people started smoking (survey years 1970, 1978, 1979, 1980, 1987, and 1988) were used to construct age-specific rates of smoking initiation for males and females 10 to 24 years of age for 1950, 1965, and 1980. We used information from 87,483 white respondents who were between 20 and 50 years of age when surveyed. In 1950, initiation was higher for males of all ages than for females, and smoking initiation rates were higher among those age 18 years and older compared to those younger. Although still somewhat higher, the rates for males in 1965 had declined much more than those for females, and the tendency for higher rates in older youth was still evident. In 1980, no gender difference was seen and most initiation clearly took place in those younger than 18 years of age. We concluded that the public health campaign has been successful in convincing older youth not to smoke. However, smoking initiation rates in younger adolescents have changed little, indicating that new approaches to tobacco control are necessary if smoking prevalence in the United States is to be further reduced.

Does vibration cause poststenotic dilatation in vivo and influence atherogenesis in cholesterol-fed rabbits?

Arterial post-stenotic dilatation (PSD) is a fusiform swelling immediately down-stream to a stenosis. It is characterized by the presence of turbulent blood flow and wall vibration which has been claimed by others to be causal by producing structural weakening. We tested the hypothesis that vibration causes PSD in vivo by attaching electromagnetic and pneumatic vibrators to the aortic wall in chronic rabbits. We also observed whether mechanical vibration of the aorta in vivo influenced the distribution of oil-red-O lesions during one percent dietary cholesterol feeding. Low mass vibration gauges were developed to measure the vibration. Electromechanical vibrators having a ceramic magnet slug within a coil supplied with 50 Hz were glued to the aorta of chronic rabbits and the vibration maintained for an average of 8 weeks. Despite greater amounts of energy imparted to the wall there was no dilatation or difference in oil-red-O staining from the controls. Five weeks vibration at 100 Hz and an amplitude equal to the normal diameter pulse also produced no dilatation. We conclude that vibration does not cause PSD in vivo and suggest that its cause is likely to involve the vascular muscle stimulated by the effect of turbulent flow on the endothelium.

Stereospecific HPLC method for the quantitation of the enantiomers of MK-0571, a potent leukotriene D4 receptor antagonist, in biological specimens

A stereospecific HPLC bioanalytical method was developed for quantitation of the enantiomers of MK-0571, a leukotriene D4 receptor antagonist. The procedure involves the addition of an internal standard analog to the biological matrix followed by extraction of the free acids into ethyl acetate. The acids are subsequently reacted with the homochiral reagent, (+)-(R)-alpha-(1-naphthyl)ethylamine (NEA) to form diastereomers. Following removal of excess reagent and side products by a dilute acid wash, the NEA-MK-0571 diastereomers are separated on a phenyl urea chiral column using a mobile phase containing hexane, isopropanol, and acetonitrile and are detected with a fluorescence detector. The sensitivity of the method is such that 50 ng of each enantiomer can be quantitated. In the 0.05 to 10 micrograms range the recoveries of the enantiomers of MK-0571 from plasma were 100.4 +/- 7.9% and 100.0 +/- 7.2%. NMR and mass spectral data confirmed the structure of the derivative. The method has been utilized in drug safety evaluation studies to demonstrate enantioselectivity in disposition of the enantiomers of MK-0571 in rats and monkeys but not in mice.

Regulation and quaternary structural changes in rabbit muscle phosphofructokinase

Subunit assembly plays a significant role in the regulation of rabbit muscle phosphofructokinase (PFK), although conformational changes and post-translational modifications have also been implicated to regulate the enzyme activity. In the absence of high-resolution structural information, the three-dimensional arrangements of subunits in the rabbit muscle PFK in its active and inactive states are not known. Hence, a systematic study is initiated, and phosphorylation of PFK subunit is employed as a probe for the structure-function correlation of the enzyme. The self-association of the phosphorylated and dephosphorylated PFK was monitored by sedimentation velocity at pH 7.0 and 23 degrees C. Results show that both the phosphorylated and dephosphorylated forms of PFK exhibit the same mechanism of assembly. The secondary structures of both forms of PFK were monitored by circular dichroism (CD) as a function of protein concentration ranging from 20 to 2000 micrograms/ml. Results show that there is no detectable difference in the structure under all experimental conditions. The accessibility of tryptophan to solvent was monitored by fluorescence quenching within the same range of protein concentration. Results show that the fluorophores are more accessible to the quencher at higher protein concentrations. Hence, post-translational modification and subunit association do not induce significant structural change in PFK subunit, although the accessibility of tryptophan residues is altered with oligomer formation. Furthermore, sedimentation and CD studies show that the activation of PFK by substrate includes no detectable modification in secondary/tertiary structure but a quaternary structural change, and the local environments of some, if not all, of the tryptophan residues are less accessible to solvent. Hence, the change in sedimentation behavior between the active and inactive tetrameric PFK is due to a rearrangement of subunit-subunit interactions. In order to correlate the physical properties of PFK to the regulatory behavior of enzyme activity, the steady-state kinetics were investigated under the same experimental conditions. In conditions where enhancement of self-association is observed, the kinetic behavior reflects activation of the enzyme. Hence, this correlation between subunit assembly and the regulation of enzyme activity in PFK must reflect an intrinsic property of the muscle enzyme.

[Study of rat control by using bait box]

This study examines the feasibility of using bait boxes for permanent rat control in Taiwan. During the test period between October 1988 and March 1989, 37 bait boxes made of PVC pipes were placed at various baiting sites in public markets, near restaurants and food stands in several communities known to be infested by rats. Each of the 37 boxes was baited with non-toxic rice powder to determine how well these boxes were accepted, the time needed for rats to use the boxes and eat the bait, and to do preliminary census on the relative densities of rat populations at these different places. The results showed that 27 of 29 (93.1%) bait boxes that had not been vandalized, disturbed or moved away and could be monitored continuously were used by rats. Of these 27 bait boxes, 13 (48.1%) were used the day after the boxes were set, and 25 (92.6%) were used within a week after the boxes were set. The amount of bait eaten per day for each bait box varied greatly, from less than 5 g to more than 300 g. After the bait in each bait box was taken regularly, half of the bait boxes with good bait acceptance were pulse-baited with 0.005% brodifacoum coated rice powder, and the other half of the bait boxes with good bait acceptance were baited with non toxic rice powder for comparison. The result of treatment indicated that rat control by using bait boxes is effective. However, the cooperation of the local people and the location of bait boxes have a great influence over the success of this control method.

Thermal stability of proteins in the presence of poly(ethylene glycols)

Thermal unfolding of ribonuclease, lysozyme, chymotrypsinogen, and beta-lactoglobulin was studied in the absence or presence of poly(ethylene glycols). The unfolding curves were fitted to a two-state model by a nonlinear least-squares program to obtain values of delta H, delta S, and the melting temperature Tm. A decrease in thermal transition temperature was observed in the presence of poly(ethylene glycol) for all of the protein systems studied. The magnitude of such a decrease depends on the particular protein and the molecular size of poly(ethylene glycol) employed. A linear relation can be established between the magnitude of the decrease in transition temperature and the average hydrophobicity of these proteins; namely, the largest observable decrease is associated with the protein of the highest hydrophobicity. Further analysis of the thermal unfolding data reveals that poly(ethylene glycols) significantly effect the relation between delta H degrees of unfolding and temperature for all the proteins studied. For beta-lactoglobulin, a plot of delta H versus Tm indicates a change in slope from a negative to a positive value, thus implying a change in delta Cp in thermal unfolding caused by the presence of poly(ethylene glycols). Results from solvent-protein interaction studies indicate that at high temperature poly(ethylene glycol) 1000 preferentially interacts with the denatured state of protein but is excluded from the native state at low temperature. These observations are consistent with the fact that poly(ethylene glycols) are hydrophobic in nature and will interact favorably with the hydrophobic side chains exposed upon unfolding; thus, it leads to a lowering of thermal transition temperature.

Dissolution of gallstones using cholecystostomy tube in the pig

Cholecystostomy catheters and human cholesterol gallstones were implanted surgically in the gallbladders of eight pigs. Through the catheters, mono-octanoin or sterile water (H2O) was infused from two to seven days. The mono-octanoin dissolved pure cholesterol gallstones smaller than 200 g. There was no stone dissolution with infusion of sterile water and only one stone larger than 250 g was dissolved with mono-octanoin. Side effects included moderate-to-severe inflammation and ulceration of the gallbladder with mono-octanoin instillation, which precludes its widespread use with the present treatment regimen. Infusion of water caused little gallbladder irritation.

A panic attack in therapeutic recreation over being considered therapeutic

Ancillary professions have been called upon to account for therapeutic benefits from their services or be eliminated from the health care system. A singular focus on therapy, however, would negate the unique contribution of therapeutic recreation within, while simultaneously restricting services to health care settings. It is proposed that panic over therapeutic recreation services meeting health care goals has hindered evaluation and solidification of the leisure-based philosophy presented in the NTRS Philosophical Position Statement (NTRS, 1982). It is argued that emphasizing the leisure orientation of the philosophical position statement can secure therapeutic recreation's position within, yet, not deny services to those outside of the health care system. An overview is presented on the adequacy of the position statement philosophy for therapeutic recreation. A potential danger of attempting to explain therapeutic recreation in terms of non-leisure based philosophies is also discussed.