Working to eliminate multiple pregnancies: a success story in Québec

In August 2010, the provincial government of Québec, Canada introduced funding of assisted reproduction treatment through the provincial health programme. Alongside this benefit, legislation was introduced to control assisted reproduction treatment activities in the province, including restrictions on the number of embryos that could be transferred in any one cycle. The aim of the programme was to transfer a single embryo in every cycle; multiple embryos could be transferred under suboptimal conditions but required physician justification. In the first 3 months of this programme, 1353 cycles of IVF were performed in five Québec assisted reproduction centres, with an overall clinical pregnancy rate of 32% per embryo transfer and 50% of transfers used elective single-embryo transfer (eSET). The multiple-pregnancy rate was only 3.7% per clinical pregnancy. In 2009, prior to the introduction of the programme, eSET was used in only 1.6% of embryo transfers, resulting in a multiple-pregnancy rate of 25.6%. These data demonstrate that providing provincially funded assisted reproduction treatment created an environment in which the aggressive use of eSET was not only possible, but also rapidly implemented. The result was a dramatic drop in multiple-pregnancy rates, approaching those for natural pregnancies.

Five-year survival of nonagenerian patients undergoing total hip replacement in the United Kingdom

Between January 2000 and December 2007, 31 patients 90 years of age or older underwent total hip replacement at our hospital. Their data were collected prospectively. The rate of major medical complications was 9%. The surgical re-operation rate was 3%. The requirement for blood transfusion was 71% which was much higher than for younger patients. The 30-day, one-year and current mortality figures were 6.4% (2 of 31), 9.6% (3 of 31) and 55% (17 of 31), respectively, with a mean follow-up for the 14 surviving patients of six years. Cox's regression analysis revealed no significant independent predictors of mortality. Only 52% of patients returned immediately to their normal abode, with 45% requiring a prolonged period of rehabilitation. This is the first series to assess survival five years after total hip replacement for patients in their 90th year and beyond. Hip replacement in the extreme elderly should not be discounted on the grounds of age alone, although the complication rate exceeds that for younger patients. It can be anticipated that almost half of the patients will survive five years after surgery.

External validation of a six simple variable model of stroke outcome and verification in hyper-acute stroke

We aimed to validate a previously described six simple variable (SSV) model that was developed from acute and sub-acute stroke patients in our population that included hyper-acute stroke patients. A Stroke Outcome Study enrolled patients from 2001 to 2002. Functional status was assessed at 6 months using the modified Rankin Scale (mRS). SSV model performance was tested in our cohort. 538 acute ischaemic (87%) and haemorrhagic stroke patients were enrolled, 51% of whom presented to hospital within 6 h of symptom recognition. At 6 months post-stroke, 42% of patients had a good outcome (mRS < or = 2). Stroke patients presenting within 6 h of symptom recognition were significantly older with higher stroke severity. In our Stroke Outcome Study dataset, the SSV model had an area under the curve of 0.792 for 6 month outcomes and performed well for hyper-acute or post-acute stroke, age < or > or = 75 years, haemorrhagic or ischaemic stroke, men or women, moderate and severe stroke, but poorly for mild stroke. This study confirms the external validity of the SSV model in our hospital stroke population. This model can therefore be utilised for stratification in acute and hyper-acute stroke trials.

Does salvage and tranexamic acid reduce the need for blood transfusion in revision hip surgery?

We carried out a retrospective case-control study in 80 patients who underwent a revision total hip replacement. Group A (40 patients) received tranexamic acid and intra-operative cell salvage. Group B (40 patients) was a matched control group and did not receive this management. Each group was divided into four subgroups: revision of both components, revision of both components with bone grafting, revision of the acetabular component with or without bone graft, and revision of the femoral component with or without bone graft. In group A the total number of units transfused was 52, compared with 139 in group B, representing a reduction in blood usage of 62.5%. The mean amount of blood transfused from cell salvage in each group was 858 ml (113 to 2100), 477 ml (0 to 2680), 228 ml (75 to 315) and 464 ml (120 to 1125), respectively. There was a significant difference in the amount of blood returned between the groups (p < 0.0001). In group A, 22 patients needed transfusion and in group B, 37 (p < 0.0001). A cost analysis calculation showed a total revenue saving of pounds sterling 70 000 and a potential saving throughout our facility of pounds sterling 318 288 per year. Our results show that a significant reduction in blood transfusion can be made using combined cell salvage and tranexamic acid in revision surgery of the hip.

Thrombogenic influence of biomaterials in patients with the Omni series heart valve: pyrolytic carbon versus titanium

An opportunity to assess the thromboembolic rates caused by the construction materials on valve replacements is possible with the Omni series of mechanical heart valves. The Omnicarbon and Omniscience valves are identical in form but differ in that the Omnicarbon valve is constructed entirely of pyrolytic carbon, whereas the Omniscience valve uses titanium for its housing, the rest of its structure being pyrolytic carbon. The literature was reviewed and a comparison in similar groups of patients was made between these two model valves for their thromboembolic rates in the mitral and aortic positions. A total of 569 aortic Omnicarbon valves (4,146 patient years [pt yrs.1) had a thromboembolic events (T/E rate) of 0.5% compared with 1.7% for 468 aortic Omniscience (1,552 pt yrs); p < 0.0001. A total of 298 mitral Omnicarbon valves (3,333 pt yrs) had a T/E rate of 1.6% compared with 2.6% for 716 mitral Omniscience valves (2,134 pt yrs), p < 0.001. There was no difference in the anticoagulation management between the two model valves although the Omniscience valve required higher prothrombin or International Normalized Rate maintenance levels, which resulted in higher bleeding rates among patients with Omniscience valves.

Thrombolytic Therapy for Acute Ischemic Stroke: The CAEP Position Statement: another perspective

The cautiously-worded Position Statement recently issued by the Canadian Association of Emergency Physicians (see Appendix 1) regarding the use of intravenous recombinant tissue-plasminogen activator (tPA, alteplase) for acute ischemic stroke underscores the reality that many physicians in Canada have been reluctant to embrace this therapy. Much of the caution expressed in the CAEP document is related to 2 major areas of concern: evidence of efficacy (i.e., did tPA really “prove” itself in randomized trials?) and effectiveness (i.e., are the trial results generalizable to everyday practice?). While we support the development of documents that help to clarify controversial treatments, and agree with much of what is presented in the CAEP Position Statement, we offer the following comments.

Glycine antagonist in neuroprotection for patients with acute stroke: GAIN Americas: a randomized controlled trial

CONTEXT

Elucidation of the ischemic cascade has helped stimulate development of neuroprotective drugs aimed at limiting brain injury in the hours following an ischemic stroke. To date, none of these drugs has shown clinical efficacy.

OBJECTIVE

To examine the efficacy of gavestinel (GV150526), an antagonist of the glycine site of the N-methyl-D-aspartate receptor, as a neuroprotective therapy for acute ischemic stroke when administered within 6 hours of symptom onset.

DESIGN

The Glycine Antagonist in Neuroprotection (GAIN) Americas trial, a randomized, double-blind placebo-controlled trial with enrollment from April 1998 to October 1999.

SETTING

One hundred thirty-two hospital centers across the United States and Canada.

PATIENTS

The primary efficacy population consisted of 1367 ischemic stroke patients with a predefined level of limb weakness and functional independence prior to stroke, stratified at randomization by age (</=75 vs >75 years) and initial stroke severity (National Institutes of Health [NIH] Stroke Scale scores of 2-5, 6-13, or >/=14).

INTERVENTION

Patients were randomly assigned to receive an intravenous loading dose (800 mg) plus 5 maintenance doses (200 mg every 12 hours) of gavestinel (n = 701) or placebo (n = 666) for 3 days.

MAIN OUTCOME MEASURE

Functional capability at 3 months, measured by the Barthel Index (BI), with scores trichotomized as dead/0-55, 60-90, and 95-100, compared between the gavestinel and placebo groups.

RESULTS

Treatment groups were well matched for baseline characteristics. For each group, median NIH Stroke Scale was 12, median age was 72 years, and median time to treatment was 5.2 hours. No statistically significant improvement on the 3-month BI trichotomy was demonstrated for gavestinel (P =.79). The proportion who were functionally independent (BI score = 95-100) was 39% in the gavestinel group and 37% in the placebo group. No statistically significant difference in 3-month survival was observed using Kaplan-Meier curves (P =.11). No other secondary end point suggested an advantage for gavestinel. Among the 333 patients (24%) who received recombinant tissue-type plasminogen activator, there was also no benefit for gavestinel (P =.53). There were no serious safety issues.

CONCLUSION

In this study, gavestinel administered up to 6 hours after an acute ischemic stroke did not improve functional outcome at 3 months.

Multiple obesity QTLs identified in an intercross between the NZO (New Zealand obese) and the SM (small) mouse strains

The inheritance of adiposity levels has been investigated in an intercross of the obese, diabetes-prone NZO and the small, lean SM mouse strains. Adiposity index (AI) was defined as the sum of four fat pad weights divided by body weight. DNA pools from fat and lean mice were analyzed with microsatellite variants to screen the genome for quantitative trait loci (QTLs) affecting AI. Ten significant QTLs affecting AI were identified on Chromosome (Chr) 1 (three loci), Chr 2, Chr 5 (two loci), Chr 6 (two loci), Chr 7, and Chr 17. Most of the QTLs appear to be novel. Several QTLs differentially affect specific fat depots. Thus, Chr 2 and Chr 7 QTLs affect gonadal more than inguinal fat, while the converse is true for the Chr 17 QTL. Gender influences the expression of several of the QTLs. For example, effects of the proximal Chr 1 QTL (Obq7) on AI appears to be primarily in males. The proximal AI QTL on Chr 6 (Obq13) maps near the neuropeptide Y (Npy) locus. Sequence analysis of the Npy gene revealed a 1-nucleotide deletion within a highly conserved portion of the 3' untranslated region in strain NZO. However, the deletion is polymorphic among mouse strains. Furthermore, lack of association between this same variant and AI in previously analyzed crosses raises doubt that it is the basis of Obq13. The present cross is the fourth in a series of intercrosses among 10 inbred strains arranged such that each strain is crossed with each adjacent strain within a circle. This design affords multiple opportunities to analyze each segregating QTL.

Poor postnatal weight gain: a risk factor for severe retinopathy of prematurity

PURPOSE

This study aimed to investigate the relationship between rate of postnatal weight gain and severity of retinopathy of prematurity (ROP).

METHODS

All infants (n = 111) screened for ROP at a single tertiary intensive care nursery over a 2-year period with an estimated gestational age of 30 weeks or less and follow-up to at least 42 weeks' postconception were included. The authors performed a retrospective review of records and statistical analysis of risk factors for ROP using multivariate analysis.

RESULTS

Infants with severe (stage 3 or greater) ROP gained an average 10.9 g/kg per day in the first 6 weeks of life, compared to a mean of 9.6 g/kg per day for those with mild or no ROP (P =.04). By multiple regression, which included birth weight, gestational age, and 9 other reported risk factors, there was an association between rate of postnatal weight gain and severity of ROP (P =.02). By stepwise regression, 4 variables were associated with ROP severity: estimated gestational age at birth (P =.002), rate of postnatal weight gain (P = .0002), volume of transfused erythrocytes (P =.0001), and culture-proven sepsis (P = .02).

CONCLUSION

Poor postnatal weight gain is a risk factor for the development of severe (stage 3 or greater) ROP. Ophthalmologists should take note of those infants who gain less than 50% of their birth weight in the first 6 weeks of life.

Physiology of wound healing and surgical wound care

Wound healing is a systemic process, which occurs stepwise and involves the stages of hemostasis, inflammation, and repair. Hemostasis with fibrin formation creates a protective wound scab. The scab provides a surface beneath which cell migration and movement of the wound edges can occur. Inflammation brings nutrients to the area of the wound, removes debris and bacteria, and provides chemical stimuli for wound repair. Repair begins immediately after wounding and proceeds rapidly through the processes of epithelialization, fibroplasia, and capillary proliferation into the healing area. Different tissues have their own normal rates of growth during the process of healing. The optimal rate of healing is approached when factors advantageous to healing are present and factors having the ability to disturb or retard the healing processes are controlled or absent. These factors are discussed.

The outcome of IVF-embryo transfer treatment in patients who develop three follicles or less

Among 828 patients undergoing IVF-embryo transfer treatment, the implantation and pregnancy rates of patients who developed < or = 3 follicles were compared prospectively with those patients who had a normal response. Patients who developed 1 to 3 follicles during ovarian stimulation elected to proceed with oocyte collection, have intrauterine insemination if appropriate, or to have their cycle cancelled. In the group of patients who developed < or = 3 follicles and who were aged <40 years, despite a significantly lower number of oocytes collected [2 versus 7; median difference (MD) = 9; confidence interval (CI) = 7-11, and lower number of embryos developed and transferred (1 versus 3; MD = 2; CI = 1-2), no difference in either implantation rate [27.8 versus 20.4%; odds ratio (OR) = 1.58; CI = 0.46-4.54] or pregnancy rate (27.8 versus 36.7%; OR = 0.7; CI = 0.2-2.0) was noted when compared with similarly aged patients who developed >3 follicles. However, in patients aged >40 years who developed < or = 3 follicles, a moderate, albeit non-significant decrease in implantation rate (3.8 versus 7.8%; OR = 1.91; CI = 0.4-57.0) and pregnancy rate (4.2 versus 18.3%; OR = 1.92; CI = 0.38-57.0) was observed when compared with patients of a similar age who developed >3 follicles. Patients aged <40 years, unlike older patients, maintain good implantation and pregnancy rates despite a poor response to ovarian stimulation. This study indicates that for this group of women, continuation of IVF treatment is a better option than cancellation.

Impact of reducing the number of embryos transferred from three to two in women under the age of 35 who produced three or more high-quality embryos

OBJECTIVE

To investigate the effect of a reduction in the number of good-quality embryos transferred in patients <35 years of age on pregnancy and multiple pregnancy rate.

DESIGN

Prospective observational study with historical controls.

SETTING

Academic tertiary referral unit.

PATIENT(S)

Three hundred eight patients <35 years of age undergoing IVF-ET.

INTERVENTION(S)

For patients who had three or more good quality embryos available for transfer, those in group 1 were given the option to have either two or three embryos replaced, whereas those in group 2 were allowed a maximum of two embryos transferred. In both groups, patients who had less than three good-quality embryos had the option to have three embryos transferred.

MAIN OUTCOME MEASURE(S)

Pregnancy and multiple pregnancy rates.

RESULT(S)

Patients in group 1, compared with those in group 2, had significantly more embryos (3 vs. 2) of significantly higher cumulative embryo score (31 vs. 24) transferred. This resulted in significantly higher multiple (57.8% vs. 30.8%) and triplet (15.6% vs. 1.4%) pregnancy rates in group 1. However, no difference in overall clinical pregnancy rate (37.2% vs. 41.2%) or live birth rate (28.1% vs. 29.4%) was observed between group 1 and 2.

CONCLUSION(S)

In women <35 years of age, who have three or more good-quality embryos available for transfer, a maximum of two embryos should generally be transferred.

Atrial fibrillation and the use of warfarin in patients admitted to an acute stroke unit

OBJECTIVES

To examine the use of warfarin in patients with atrial fibrillation (AF) admitted to hospital because of stroke or transient ischemic attack; and to describe the outcome of AF-associated stroke.

DESIGN

Review of the medical records of patients, identified from a prospective registry, admitted from January 1, 1994 through December 31, 1996.

SETTING

Tertiary care teaching hospital.

RESULTS

AF was present in 92 of 722 (13%) patients at the time of admission. Only eight of 60 (13%) patients with ischemic stroke who were known to be in AF before their stroke were taking warfarin. The in-hospital case-fatality ratio for AF patients was more than double that of patients in sinus rhythm (21% versus 9%, respectively, P=0.001). AF patients were less likely to be discharged home (31% versus 59%, P=0.005). Of the 68 AF patients who survived, 74% left hospital taking warfarin. No warfarin-treated patient experienced intracranial bleeding while in hospital or during follow-up.

CONCLUSIONS

Patients with AF had more severe strokes than patients in sinus rhythm. A small proportion of patients with known AF were taking warfarin at the time of hospitalization. Bleeding complications were infrequent. Broader implementation of guidelines for the management of AF is justified to reduce the frequency of stroke in this group of patients.

How Baby-Friendly are Manitoba hospitals? The Provincial Infant Feeding Study. Breastfeeding Promotion Steering Committee of Manitoba

The Breastfeeding Promotion Steering Committee of Manitoba conducted the cross-sectional Provincial Infant Feeding Study in 1996 to examine: correlation between breastfeeding policies and actual practices in Manitoba hospitals; compliance with Baby-Friendly Hospital Initiative (BFHI) criteria; and associations between hospital practices and two-week breastfeeding duration. Three separate surveys obtained information from: administrators concerning hospital policy; nursing staff concerning hospital practices; and all women giving birth in a five-week period, concerning breastfeeding rates and maternal perceptions of hospital practices. The results highlighted the need for policy and practice changes to comply with BFHI criteria. 92% initiated breastfeeding, and 84% were breastfeeding at two weeks postpartum. Independent predictors of weaning included: in-hospital supplementation (adjusted RR = 2.1, 95% CI 1.02-4.36, p = 0.04); temporarily interrupting breastfeeding while in hospital (adjusted RR = 4.9, 95% CI 2.7-8.9, p = 0.0001); no previous breastfeeding experience (adjusted RR = 2.5, 95% CI 1.4-4.4, p = 0.002); and Grade 12 or less maternal education.

Gender-influenced obesity QTLs identified in a cross involving the KK type II diabetes-prone mouse strain

The inheritance of adiposity and related traits has been investigated in the obese, diabetes-prone KK/HlLt (KK) and the lean, normoglycemic C57BL/6J (B6) mouse strains, their F(1) hybrids, and a large intercross generation. Adiposity index (AI) was defined as the sum of four fat depot weights divided by body weight. Both male and female KK mice were obese, but AI values averaged twofold higher in females than in males. In contrast, B6 females were slightly more lean than males. A genome-wide search revealed several qualitative trait loci (QTLs) affecting AI. The proximal region of Chromosome (Chr) 9 has a large effect on AI, with a much stronger effect in females (lod = 6.3) than in males (lod = 2.7). The data for females fit a model in which a dominant allele from KK increases AI by 30%, with the lod score peak falling between markers D9Mit66 and D9Mit328. This QTL has large effects on inguinal and mesenteric fat pad weights, with smaller effects on gonadal and retroperitoneal fat pads. The region of Chr 9 containing this QTL has extensive homology to human Chr 11q. An X-linked QTL affecting AI was evident in males (lod = 3.77), but not females (lod = 0.7). Exclusion of mesenteric fat from male AI resulted in an increased lod score (lod = 5.0) at 8 cM distal to DXMit166. A suggestive AI QTL (lod = 4.2), differentially affecting males, was localized to Chr 18 near the glucocorticoid receptor locus. A region of Chr 7 had a strong effect on body weight (lod = 6.9), a significant effect on inguinal fat% (lod = 4.4), and a suggestive effect on AI in females (lod = 4.1). Plasma leptin levels were associated with genotypes on Chr 9 (lod = 5.9) and Chr 7 (lod = 4.2). A region of Chr 1 had a suggestive effect on fasted blood glucose (lod = 3.6).

Genotyping new BXD recombinant inbred mouse strains and comparison of BXD and consensus maps

Nine additional BXD recombinant inbred (RI) strains have been developed from the F2 cross of C57BL/6J and DBA/2J mouse strains. A tenth line stopped breeding in the F12 generation. F20 generation breeding pairs from the nine surviving strains and an F12 pair from the extinct line were genotyped at 319 genetic markers (primarily microsatellites) spanning most of the genome. Where typing data were lacking, the established set of 26 BXD strains also were genotyped at these same loci. The availability of these additional nine strains enhances the value of the BXD RI set for analysis of complex phenotypic traits. The proportion of loci still segregating at the F20 generation was found to closely approximate expectation, suggesting that selection favoring the retention of heterozygosity is not a strong factor. However, the number of crossovers between adjacent markers was frequently less than predicted from consensus map distances. A significant deficiency of recombinants was observed on Chrs 3, 4, 14, and X. On Chr 14, the estimated cumulative BXD map distance between the most proximal and distal markers was only 30.2 cM, compared with a distance of 60.0 cM in the consensus map. On the X Chr, the estimated and predicted cumulative distances were 38.8 and 69.5 cM, respectively. Over all chromosomes, the BXD RI map is 14.5% shorter than predicted from the consensus map. It is suggested that distances in some of the consensus maps are inflated. Alternatively, recombinant genotypes could be selected against during inbreeding owing to allelic interactions affecting fitness. The latter interpretation implies that relatively strong intrachromosomal epistasis is common.

Fatigue after stroke

OBJECTIVE

To determine the frequency and outcome of fatigue, its impact on functioning, and its relationship with depression in patients 3 to 13 months poststroke.

DESIGN

Survey.

SETTING

Community.

PARTICIPANTS

Eighty-eight individuals from a pool of 181 consecutive patients previously admitted to an acute stroke service who were willing and able to complete the self-report questionnaires, and 56 elderly controls living independently in the community.

MAIN OUTCOME MEASURES

Fatigue Impact Scale (a self-report measure of the presence and severity of fatigue and its impact on cognitive, physical, and psychosocial functions) and the Geriatric Depression Scale.

RESULTS

The frequency of self-reported fatigue problems was greater in the stroke group (68%) than in the control group (36%, p < .001) and was not related to time poststroke, stroke severity, or lesion location. Forty percent of the stroke group reported that fatigue was either their worst or one of their worst symptoms. Patients attributed more functional limitations to their fatigue than did control subjects with fatigue. Although the presence of fatigue was independent of depression, the impact of fatigue on functional abilities was strongly influenced by depression.

CONCLUSION

Fatigue can contribute to functional impairment up to 13 months after stroke, and its recognition and treatment are important for maximizing recovery.

Hyperleptinemia and leptin receptor variant Asp600Asn in the obese, hyperinsulinemic KK mouse strain

KK obese mice exhibit a multigenic syndrome of moderate obesity, hyperinsulinemia and hyperglycemia. Here we show that the syndrome is accompanied by a marked elevation of leptin protein in adipose tissue, as well as leptin levels in serum, which corresponds with the degree of obesity. The cDNA sequence of leptin is normal in KK mice, whereas three nucleotide polymorphisms were found in the cDNA of the leptin receptor, one of them resulting in exchange of an aspartate residue for asparagine (Asp600Asn) in a highly conserved part of the second extracellular cytokine-receptor homology module. In female (but not male) F2 mice of a C57BL/6JxKK intercross, the weight of gonadal, retroperitoneal and mesenteric adipose tissue was positively correlated with the number of alleles inherited from the KK parental strain at a microsatellite marker (D4Mit175) which maps close (0.7 centimorgan proximal) to the leptin receptor gene. It is suggested that the Asp600Asn leptin receptor variant contributes to the obesity syndrome in KK female mice, but that its contribution is only a part of the multigenic syndrome.

Prediction of infarct topography using the Oxfordshire Community Stroke Project classification of stroke subtypes

BACKGROUND

The Oxfordshire Community Stroke Project clinical classification of ischemic stroke syndromes has been shown to be predictive of important clinical outcomes. In this study, we examined the correlation between this classification system and infarct topography on computed tomography (CT) of the brain.

METHOD

A cohort of consecutive cases of acute ischemic stroke admitted to an acute stroke service during the 3-year period ending December 31, 1996 were identified from a prospective stroke registry. Brain scans were reviewed by a single neuroradiologist without knowledge of the clinical features.

RESULTS

There were 418 patients with acute ischemic stroke who met the study admission criteria. Forty patients were excluded, 20 (5%) did not have a CT scan during the admission, and 20 scans were not available for review. In 239 of 378 patients (63%), the brain scan revealed the lesion responsible for the clinical syndrome. In patients with positive scans, the positive predictive values of the clinical subtypes were: 86% (95% confidence interval, 78-94) for the total anterior territory stroke syndrome, 96% (92-100) for the partial anterior territory stroke syndrome, 99% (97-100) for the lacunar stroke syndrome, and 100% for the posterior circulation stroke syndrome.

CONCLUSION

The Oxfordshire Community Stroke Project classification of ischemic stroke syndromes usefully predicts infarct topography on CT scan.

Canadian guidelines for intravenous thrombolytic treatment in acute stroke. A consensus statement of the Canadian Stroke Consortium

BACKGROUND

The thromobolytic drug, tissue plasminogen activator (tPA) has been approved in the United States for the treatment of acute ischemic stroke amid controversy and concern about the balance of risk and benefit. The Canadian Stroke Consortium (CSC), a national network of neurologists who collaborate on joint projects in stroke medicine, including clinical trials and consensus statements, has developed guidelines for the use of tPA in Canada.

METHODS AND RESULTS

The CSC Board of Directors wrote a preliminary report based on existing publications, including randomized drug trials and the report of a special committee struck by the Stroke Council of the American Heart Association. This draft was circulated to the CSC membership-at-large for suggestions or amendments, to produce this final draft.

CONCLUSIONS

The present guidelines have been devised to represent a Canadian viewpoint of management. The Health Protection Branch of the Ministry of Health of Canada has not yet produced an evaluation. Further modification of these guidelines may be necessary when more data from clinical trials and experience with the drug become available.

Alterations in sheep fetal right ventricular tissue with induced hemodynamic pressure overload

We report on the cellular and molecular effects of acute and chronic hemodynamic overload on the fetal sheep heart. In one fetus of a twin gestation, the pulmonary artery was banded to create a condition of hemodynamic pressure overload in the right ventricle. The effects of this overload on the right ventricle (RV), left ventricle (LV), and intra-ventricular septum (IVS) of the heart were studied and compared to that in a control, unbanded twin fetus. At the cellular level, the histological data showed that both the size of the nuclei and the overall cell size of cardiac myocytes were increased after five days of banding; although, with one hour of banding no effects were detected at the cellular level. Based on prior studies on connexins which showed their involvement in differentiation, remodeling, and response to load we looked at their expression in control and experimental hearts. At the molecular level, changes in expression of connexin isoforms, the main gap junction protein in the heart, were observed after both one hour and five days of banding. Changes were observed in expression of connexins 40, 43, and 45. For connexin 43 there was a significant reduction confined to the right ventricle, in the chronically treated fetus, whereas, connexins 40 and 45 expression decreased after acute overload. These early molecular changes are significant because the "functional syncytium" of the myocardium is established through the gap junction connections. Alterations in connexin isoform expression affect the development, mechanical, and electrophysiological properties of the heart muscle. These changes may contribute to the ultimate result of continued hemodynamic stress on the right ventricle: heart failure.

Pyrimethamine impairs host resistance to infection with Listeria monocytogenes in BALB/c mice

Increased mortality has been observed when HIV-infected patients were treated with pyrimethamine (Pyr) as prophylaxis for toxoplasmic encephalitis, suggesting that Pyr might possess immunosuppressive activity. To analyze this in an animal model, immune function was assessed in BALB/c mice using a battery of in vivo and ex vivo assays and an in vivo model of host resistance to Listeria monocytogenes infection. Treatment for 30 days with 60 mg/kg Pyr decreased circulating white blood cell and lymphocyte counts but not neutrophil, red blood cell, or platelet counts or hemoglobin levels. Splenic B cell percentages and lipopolysaccharide-induced B cell proliferation decreased significantly after treatment with 60 mg/kg Pyr, as did levels of anti-keyhole limpet hemocyanin (KLH) IgM in serum 7 days after immunization with KLH. Anti-KLH IgG levels 14 days after immunization were not affected. Percentages of splenic T cells and macrophages and T cell proliferation in the presence of concanavalin A or allogeneic cells were not decreased by Pyr treatment. An ex vivo assay of T-cell-mediated cytotoxicity was also unaffected. When host resistance to L. monocytogenes infection was assessed, dramatic increases in mortality were observed in Pyr-treated compared to control mice. Increased numbers of L. monocytogenes organisms were observed in liver and spleen of Pyr-treated mice, compared to controls. The reduction in Listeria resistance, which is T cell mediated, contrasts with the fact that no significant changes in T-cell-mediated immunity were observed. It is possible that Pyr affects parameters of innate immunity, which were not monitored in this study.

Obesity QTLs on mouse chromosomes 2 and 17

The inheritance of obesity has been analyzed in an intercross between the mouse strains AKR/J and C57L/J. Two novel obesity quantitative trait loci (QTLs) have been identified using the strategy of selective DNA pooling. One QTL affecting adiposity, Obq3, was mapped to a 39-cM segment near the middle of Chromosome 2, with a peak lod score (5.1) just distal to the D2Mit15 locus. The AKR/J Obq3 allele confers increased adiposity in a nearly additive manner, and males are more affected than females. A second obesity QTL (Obq4) maps to the centromeric end of Chromosome 17, with a lod score peak of 4.6 at D17Mit143. The obesity-conferring allele is contributed by C57L/J and acts in a recessive or an additive manner. Obq4 also has more influence in males and affects the inguinal fat depot differentially. Obq3 and Obq4 account for 7.0 and 6.1% of the phenotypic variance in adiposity (gender-merged data), respectively. The possible relationships between these QTLs and previously described obesity QTLs and candidate genes are discussed. The large number of different obesity QTLs that have been described in mice and the relatively small effects contributed by individual loci suggest considerable genetic complexity.

TTF-2, a new forkhead protein, shows a temporal expression in the developing thyroid which is consistent with a role in controlling the onset of differentiation

Expression of thyroglobulin (Tg) and thyroperoxidase (TPO) genes in thyroid follicular cells occurs in the mouse at embryonic day (E)14.5. Two transcription factors, TTF-1 and Pax-8, have been implicated in transcriptional activation of Tg and TPO, even though the onset of their expression is at E9.5, suggesting that additional events are necessary for transcriptional activation of Tg and TPO genes. We report in this paper the cloning of TTF-2, a DNA binding protein that recognizes sites on both Tg and TPO promoters. TTF-2 is a new forkhead domain-containing protein whose expression is restricted to the endodermal lining of the foregut and to the ectoderm that will give rise to the anterior pituitary. TTF-2 shows transient expression in the developing thyroid and anterior pituitary. In the thyroid, TTF-2 expression is down-regulated just before the onset of Tg and TPO gene expression, suggesting that this transcription factor plays the role in development of a negative controller of thyroid-specific gene expression.

Mapping and retinal phenotype of the hugger mutation in the mouse

Hugger, hug, is a recessively expressed mutation in mice that features mildly abnormal locomotion, not yet explained, and a unique combination of developmental and degenerative retinal abnormalities. Analysis with the efficient MEV linkage testing stock established that hug is on mouse Chr 19 about 14 cM from th centromere, between the microsatellite markers D19Mit28 and D19Mit14. An abnormal retinal phenotype was recognized on the day of birth, when some retinal ganglion cells already lie in abnormal positions in the inner plexiform layer. By postnatal day 18 the number of neurons is reduced in all three cellular layers of the retina. Rod photoreceptor cells develop only rudimentory outer segments, and by 9 months of age, about 75% of the photoreceptor cells have completely disappeared. Similar photoreceptor cell abnormalities are seen in prph2 (formerly rds) homozygotes, which lack the peripherin/rds protein of the rod outer segments, but a mating of the respective homozygotes yielded normal progeny. Rom1, which codes for an outer segment protein similar to peripherin/rds, maps to a more proximal position on Chr 19.

Mapping in the region of Danforth's short tail and the localization of tail length modifiers

We have used an interspecific backcross to generate a detailed genetic map around the mouse tail and kidney developmental mutation Danforth's short tail (Sd). The map includes 14 simple sequence repeat (SSR) markers and four genes in a 5-cM region encompassing Sd. In addition we have used a DNA pooling approach to carry out a genome scan to localize quantitative trait loci (QTL) that modify the tail length of Sd progeny of the backcross. This has allowed us to identify a major QTL on chromosome 10 in the region of nodal and three other putative tail length QTL on chromosomes 1, 9, and 18.

Detection of obesity QTLs on mouse chromosomes 1 and 7 by selective DNA pooling

The inheritance of obesity has been analyzed in an intercross between the lean 129/Sv mouse strain and the obesity-prone EL/Suz mouse strain. The weights of three major fat pads were determined on 4-month-old mice, and the sum of these weights, divided by body weight, was used as an adiposity index. The strategy of selective DNA pooling was used as a primary screen to identify putative quantitative trait loci (QTLs) affecting adiposity index. DNA pools representing the leanest 15% and fattest 15% of the F2 progeny were compared for differential allelic enrichment using widely dispersed microsatellite variants. To evaluate putative QTLs, individual genotyping and interval mapping were employed to estimate QTL effects and assess statistical significance. One QTL affecting adiposity index, which accounted for 12.3% of phenotypic variance in gender-merged data, was mapped to the central region of Chromosome (Chr) 7. The QTL allele inherited from EL conferred increased adiposity. A second QTL that accounts for 6.3% of phenotypic variance was identified on Chr 1 near D1Mit211. At both QTLs, the data are consistent with dominant inheritance of the allele contributing to obesity. The possible relationships between these QTLs and previously described obesity QTLs, major obesity mutations, and candidate genes are discussed.

Synthesis and characterization of 8-methoxy-2'- deoxyadenosine-containing oligonucleotides to probe the syn glycosidic conformation of 2'-deoxyadenosine within DNA

The synthesis of 8-methoxy-2'-deoxyadenosine (moA) protected at N6 as an N,N-dimethylformamidine derivative and incorporation of the modified nucleoside into oligodeoxynucleotides via the phosphoramidite method are described. UV thermal denaturation studies were conducted on duplexes containing moA:G, moA:C and moA:T base pairs to determine the thermodynamic stability of duplexes containing moA relative to their adenosine (A)-containing counterparts. In the case of moA:G base pairs the effect of moA substitution is sequence dependent. In A:G mismatch-containing sequences, which have been shown by structural characterization to have a syn conformational preference at the glycosidic bond of A, moA substitution results in stabilization of the duplex. In contrast, in sequences where the A in the A:G mismatch has been shown to prefer the anti conformation moA substitution is destabilizing to the duplex. Thus moA may be a useful probe for investigating the conformational preferences of the N-glycosidic bond of adenosine within DNA. In addition, moA nucleoside is more resistant to acid-catalyzed depurination than previously described 8-bromo-2'-deoxyadenosine, allowing for facile incorporation into oligonucleotides via automated solid phase DNA synthesis.

Typing recombinant inbred mouse strains for microsatellite markers on chromosomes 10, 16, 18, 19, and X

A total of 57 different microsatellite variants have been typed in one or more of five different sets of recombinant inbred (RI) mouse strains. The present report concentrates on markers for Chromosomes (Chrs) 10, 16, 18, 19 and X. These markers extend the regions swept in these RI strains, provide reference markers for integrating RI and conventional maps, and provide additional estimates of genetic distances. Multilocus maps, based on maximum likelihood analysis of present and previously published RI SDPs on five chromosomes, are presented. Unexpectedly, three microsatellite markers, previously assigned to Chr 10, detected polymorphic fragments mapping to other chromosomes.

For young jumpers, differences are in the movement's control, not its coordination

Previous research on the development of jumping has indicated that the coordination of the jump is stable from its inception, but that individual differences lie in the control of the task. The purpose of this study was to examine control in the vertical jump as performed by novice jumpers. Two groups of children who varied in their ability to regulate the takeoff angle were compared on measures of coordination and control. The children's groups were also compared to a group of skilled adults. Both children's groups demonstrated temporal coordination patterns comparable to the adult pattern, though the children were distinguished from the adults on selected spatial (control) measures. The results indicate that a mature pattern of coordination for the jump exists at the earliest stages of the behavior's appearance in the movement repertoire. The novice, however, lacks the ability to precisely control, or tune, the movement to task demands.

Heaven can wait

The apparently unlimited demand for health care, finite supply of resources, the internal social market and continuous technological advances have given rise to increasing concern about the performance of health services. We examine an important measure of health care performance--avoidable mortality. Studies extending the scope of avoidable mortality and other outcome indicators are discussed. Although avoidable mortality is limited to providing a warning signal of possible health care deficiencies and is not an appropriate measure for all types of intervention, it still provides us with one of the best guides to the performance of health services.

Resuscitation for cardiogenic shock with extracorporeal membrane oxygenation systems

Between 1975 and 1993, 73 patients in cardiogenic shock were supported by a variety of venoarterial pumping (VAP) systems. There were 64 adults and 9 children. Shock was caused by myocardial infarction (MI) (26), failed percutaneous transluminal coronary angioplasty (PTCA) (25), post open heart surgery (9), viral cardiomyopathy (5), idiopathic cardiomyopathy (2), pulmonary embolism (2), hypothermia (2), and arrhythmia (2). Forty-three patients were treated with percutaneous bypass and 30 by surgical bypass. Resuscitated patients were usually bridged to further therapies such as coronary artery bypass graft (CABG), valve repair or replacement or cardiac transplantation. Overall, 35 patients (48%) survived VAP and additional therapies. We conclude that early application of complete cardiopulmonary support to patients in shock allows resuscitation and corrective therapy with an acceptable salvage rate.

PCR-amplification of simple sequence repeat variants from pooled DNA samples for rapidly mapping new mutations of the mouse

A novel strategy for rapidly mapping new mutations of the mouse is presented and tested. The inbred Mus musculus castaneus strain CAST/Ei is used as a tester stock. Separate DNA pools are made from mutant and wildtype intercross (F2) progeny and analyzed using simple sequence repeat (SSR) variants detected using PCR amplification. Linkage is indicated if the mutant DNA pool is enriched for the mutant-strain SSR allelic fragment in comparison with the wildtype pool and controls. The expected contributions of the tester stock to mutant and wildtype pools as a function of recombination frequency are derived for both intercross and backcross progeny segregating for a recessive mutant gene. The sensitivity and reliability of this method is investigated using arbitrary DNA mixtures and also mutant and wildtype pools from a (CAST/Ei x MEV) intercross segregating for the dilute coat color mutation. It is concluded that linkages as great as 20 cM can be reliably detected by this method provided that sufficient progeny contribute to the pools. A set of 39 SSR variants, resolvable by agarose gel electrophoresis and suitable for pooled-SSR analysis, is identified. These are expected to screen 94% of the autosomal genome in crosses between CAST/Ei and common laboratory strains.

A longitudinal study of intralimb coordination in the first year of independent walking: a dynamical systems analysis

Using a dynamical systems approach, we examined the development of intralimb coordination over the first year of independent walking. The segmental motion of the thigh and shank and their intralimb coordinative relationship were modeled dynamically as a system of coupled limit cycles. To test the predictions of such a dynamic model in the development of intralimb coordination, 3 infants were filmed from the onset of their first upright independent walking steps, and weekly for the next month and then every month thereafter until they had been walking for 1 year. 3 adults also were included for comparison. Analysis of the kinematic data derived from the film revealed that at the emergence of walking, the limit cycle system displayed instability in several aspects. With walking experience, however, the limit cycle regime became more attractive, such that by 3 months of walking the infants appeared to have found an adult-like stable coordinative relationship between the 2 segments. This pattern of instability followed by stability is consistent with the transitional behaviors of dynamical systems. Several potential control parameters are discussed that might contribute to the stabilization of the walking behavior. The utility of employing a dynamical systems approach for understanding developing behavioral systems is discussed.

A disposable heart-lung machine. Results of animal testing

A small wave propagation pump (WPP) was incorporated into oxygenators to create a disposable heart-lung machine. The WPP provides undirectional micropulsatile laminar flow of 8 L/min against 800 mmHg. The smaller WPP can generate 4 L/min against 400 mmHg (cardioplegia), or reversed, and can create up to 150 mmHg negative pressure for suction. Power needs were 110 volts and 0.5 amps or 24 volts DC and 1.5 amps. The WPP is self priming (20 cc) and de-aired in less than 3 min. Seven dogs (average weight, 36 kg) were supported for 3 hrs. Flows could accurately be adjusted from 0.005 to 8 L/min. Flow through the oxygenator and perfusion circuit averaged 3.1 L/min (2.0 to 4 L/min). Serial analysis of blood samples showed minimal hemolysis and no significant change in hematocrit, hemoglobin, white blood count, red blood count, or platelet count (p > 0.01). The inexpensive WPP oxygenator combination function as a disposable heart-lung machine.

Coronary angioplasty for acute myocardial infarction in a hospital without cardiac surgery

We evaluated, retrospectively, the hospital records of 100 consecutive patients with acute myocardial infarction who underwent emergency coronary angiography and percutaneous transluminal coronary angioplasty between January 1984 and August 1990. Intracoronary streptokinase (250,000 to 1 million units) was administered to 46 of these patients. Reperfusion was achieved in 82 patients, 8 of whom died in the hospital within 30 days. Angioplasty failed in 18 patients. Six were managed medically and survived, 7 survived emergency coronary bypass surgery at a nearby facility, and 5 died. The overall mortality rate was 13%. No facilities for open-heart surgery were available at our hospital; however, surgical back-up was available at another hospital, 0.5 miles away. No death was related to the transfer of a patient or to the unavailability of an in-house cardiac surgery facility. The American College of Cardiology/American Heart Association Task Force on Assessment of Diagnostic and Therapeutic Cardiovascular Procedures has written guidelines for cardiac surgical back-up for percutaneous transluminal coronary angioplasty. These guidelines strongly recommended that an experienced cardiovascular surgical team be available for emergency surgery in the institution as a back-up for all angioplasty procedures. Our study shows, however, that with careful case selection, emergency angioplasty for acute myocardial infarction can be performed safely with good results in a setting without on-site cardiac surgery facilities.

Benefits of combined balloon pumping and percutaneous cardiopulmonary bypass

Sixteen patients (2 women, 14 men) aged 29 to 72 years with continued cardiogenic shock during intraaortic balloon pumping (IABP) had additional treatment with percutaneous cardiopulmonary bypass (PBY). Cause of cardiogenic shock was myocardial infarction in 7 (3 survived), failed percutaneous transluminal coronary angioplasty requiring emergency coronary artery bypass grafting in 5, postoperative aortic valve replacement in 1, postoperative emergency coronary artery bypass grafting in 1, after cardiac transplantation in 1, and bridging to transplantation in 1. Mean blood pressure with PBY and IABP combined was 75 mm Hg versus 60 mm Hg with IABP off. Percutaneous cardiopulmonary bypass flows ranged from 0.8 to 2.1 L/min with a mean flow of 1.3 L/min. Time on IABP ranged from 24 hours to 1 week. Time on IABP to PBY ranged from 1 to 20 hours, and time on PBY ranged from 65 minutes to 20 hours. Ten of 16 (63%) were successfully weaned, and 3 died after weaning. Seven of 16 (44%) survive. Combined IABP with PBY appears to be a better therapy than either one individually. Staging the therapy as the balloon first in and last out appears to be a good methodology.

Relationship of cardiac disease to stroke occurrence, recurrence, and mortality

BACKGROUND AND PURPOSE

This is a study of cardiac diseases associated with the 1,382 cases of first cerebral infarction in residents of Rochester, Minn., during 1960-1984.

METHODS

This is a population-based study in Rochester, Minn., for which the medical record-linkage system was used to identify cardiac disease among patients with first cerebral infarction.

RESULTS

There were 318 patients (23%) who had at least one major potential cardiac source of emboli. The proportion of patients with a cardiac source of emboli was significantly higher among patients older than age 75 years (29%) than among younger patients (17%). The 30-day stroke recurrence rate among patients with a cardiac source of emboli (2%) was not significantly different than that among those without a cardiac source of emboli (2%). Among patients with a cardiac source of emboli, there was no difference in the probability of stroke at 30 days and at 90 days for those treated or not treated with anticoagulants. During the first 30 days after cerebral infarction, the risk of death in patients with a cardiac source of emboli (23%) was 14 times that of recurrent stroke. The risk of death at 30 days in patients without a cardiac source of emboli was 8%.

CONCLUSIONS

Significant independent predictors of death (Cox proportional-hazards analysis) were age, prior myocardial infarction, atrial fibrillation present at onset of stroke, congestive heart failure before the stroke, and an age x congestive heart failure interaction. The only significant independent predictors of recurrent stroke were cardiac valve disease and congestive heart failure.