Dose response to postruminal urea in lactating dairy cattle

Inclusion of urea in dairy cattle diets is often limited by negative effects of high levels of feed urea on dry matter intake (DMI) and efficiency of rumen N utilization. We hypothesized that supplying urea postruminally would mitigate these limitations and allow greater inclusion of urea in dairy cattle diets. Four rumen-fistulated Holstein-Friesian dairy cows (7 ± 2.1 lactations, 110 ± 30.8 d in milk; mean ± standard deviation) were randomly assigned to a 4 × 4 Latin square design to examine DMI, milk production and composition, digestibility, rumen fermentation, N balance, and plasma constituents in response to 4 levels of urea continuously infused into the abomasum (0, 163, 325, and 488 g/d). Urea doses were targeted to linearly increase the crude protein (CP) content of total DMI (diet plus infusion) by 0%, 2%, 4%, and 6% and equated to 0%, 0.7%, 1.4%, and 2.1% of expected DMI, respectively. Each 28-d infusion period consisted of a 7-d dose step-up period, 14 d of adaptation, and a 7-d measurement period. The diet was fed ad libitum as a total mixed ration [10.9% CP, 42.5% corn silage, 3.5% grass hay, 3.5% wheat straw, and 50.5% concentrate (dry matter basis)] and was formulated to meet 100%, 82%, and 53% of net energy, metabolizable protein, and rumen-degradable protein requirements, respectively. Linear, quadratic, and cubic effects of urea dose were assessed using polynomial regression assuming the fixed effect of treatment and random effects of period and cow. Dry matter intake and energy-corrected milk yield responded quadratically to urea dose, and milk urea content increased linearly with increasing urea dose. Apparent total-tract digestibility of CP increased linearly with increasing urea dose and ruminal NH3-N concentration responded quadratically to urea dose. Mean total VFA concentration was not affected by urea dose. The proportion of N intake excreted in feces decreased linearly and that excreted in urine increased linearly in response to increasing urea dose. The proportion of N intake excreted in milk increased linearly with increasing urea dose. Urinary urea excretion increased linearly with increasing urea dose. Microbial N flow responded cubically to urea dose, but the efficiency of microbial protein synthesis was not affected. Plasma urea concentration increased linearly with increasing urea dose. Regression analysis estimated that when supplemented on top of a low-CP diet, 179 g/d of postruminal urea would maximize DMI at 23.4 kg/d, corresponding to a dietary urea inclusion level of 0.8% of DMI, which is in line with the current recommendations for urea inclusion in dairy cattle diets. Overall, these results indicate that postruminal delivery of urea does not mitigate DMI depression as urea dose increases.

Essential amino acid profile of supplemental metabolizable protein affects mammary gland metabolism and whole-body glucose kinetics in dairy cattle

This study investigated mammary gland metabolism and whole-body (WB) rate of appearance (Ra) of glucose in dairy cattle in response to a constant supplemental level of metabolizable protein (MP) composed of different essential AA (EAA) profiles. Five multiparous rumen-fistulated Holstein-Friesian dairy cows (2.8 ± 0.4 lactations; 81 ± 11 d in milk; mean ± standard deviation) were abomasally infused according to a 5 × 5 Latin square design with saline (SAL) or 562 g/d of EAA delivered in different profiles where individual AA content corresponded to their relative content in casein. The profiles consisted of (1) a complete EAA mixture (EAAC), (2) Ile, Leu, and Val (ILV), (3) His, Ile, Leu, Met, Phe, Trp, Val (GR1+ILV), and (4) Arg, His, Lys, Met, Phe, Thr, Trp (GR1+ALT). A total mixed ration (58% corn silage, 16% alfalfa hay, and 26% concentrate on a dry matter basis) was formulated to meet 100 and 83% of net energy and MP requirements, respectively, and was fed at 90% of ad libitum intake on an individual cow basis. Each experimental period consisted of 5 d of continuous abomasal infusion followed by 2 d of no infusion. Arterial and venous blood samples were collected on d 4 of each period for determination of mammary gland AA and glucose metabolism. On d 5 of each period, D-[U-¹³C]glucose (13 mmol priming dose; continuous 3.5 mmol/h for 520 min) was infused into a jugular vein and arterial blood samples were collected before and during infusion to determine WB Ra of glucose. Milk protein yield did not differ between EAAC, GR1+ILV, and GR1+ALT, or between SAL and ILV, and increased over SAL and ILV with EAAC and GR1+ILV. Mammary plasma flow increased with ILV infusion compared with EAAC and GR1+ILV. Infusion of EAAC tended to increase mammary gland net uptake of total EAA and decreased the mammary uptake to milk protein output ratio (U:O) of non-EAA compared with SAL. Infusion of ILV increased mammary net uptake and U:O of Ile, Leu, and Val markedly over all treatments. The U:O of total Ile, Leu, and Val increased numerically (25%) with GR1+ILV infusion compared with EAAC, and the U:O of total Arg, Lys, and Thr tended to decrease, primarily from decreased U:O of Lys. During GR1+ALT infusion, U:O of total Arg, Lys, and Thr was greater than that during EAAC infusion, whereas U:O of Ile, Leu, and Val did not differ from EAAC. Glucose WB Ra increased 16% with GR1+ALT over SAL, and increased numerically 8 and 12% over SAL with EAAC and GR1+ILV, respectively. The average proportion of lactose yield relative to glucose WB Ra did not differ across treatments and averaged 0.53. On average, 28% of milk galactose arose from nonglucose precursors, regardless of treatment. In conclusion, intramammary catabolism of group 2 AA increased to support milk component synthesis when the EAA profile of MP was incomplete with respect to casein. Further, WB and mammary gland glucose metabolism was flexible in support of milk component synthesis, regardless of absorptive EAA profile.

Proton stopping measurements at low velocity in warm dense carbon

Ion stopping in warm dense matter is a process of fundamental importance for the understanding of the properties of dense plasmas, the realization and the interpretation of experiments involving ion-beam-heated warm dense matter samples, and for inertial confinement fusion research. The theoretical description of the ion stopping power in warm dense matter is difficult notably due to electron coupling and degeneracy, and measurements are still largely missing. In particular, the low-velocity stopping range, that features the largest modelling uncertainties, remains virtually unexplored. Here, we report proton energy-loss measurements in warm dense plasma at unprecedented low projectile velocities. Our energy-loss data, combined with a precise target characterization based on plasma-emission measurements using two independent spectroscopy diagnostics, demonstrate a significant deviation of the stopping power from classical models in this regime. In particular, we show that our results are in closest agreement with recent first-principles simulations based on time-dependent density functional theory.

Charged particle interaction and energy dissipation in plasma is fundamentally interesting. Here the authors study proton stopping in laser-produced plasma for the moderate to strong coupling with electrons.

O-238 Preterm birth after recurrent pregnancy loss: A systematic review and meta-analysis

Study question

What is the impact of recurrent pregnancy loss on the risk of preterm birth?

Summary answer

Women with RPL were found to be at increased odds of having preterm deliveries (<37 weeks gestation) in their subsequent live pregnancies.

What is known already

Recurrent pregnancy loss (RPL) occurs in up to 5% of all women with miscarriages. The emotional, physical, and financial burden associated with RPL is unequivocal, and over the years, much research has gone into the management of RPL. However, relatively little is known about the perinatal outcomes following RPL. Past research in the area reports conflicting data on the association between RPL and preterm birth (PTB) in a subsequent pregnancy.

Study design, size, duration

A systematic search was performed across thePubMed, EMBASE and Google Scholar databases for relevant studies published up until October 2020. Observational cohort and case-control studies comparing the risk of preterm birth (PTB) among women with and without a history of RPL were included. Effect estimates were pooled using a DerSimonian and Laird random-effects meta-analysis model. Study appraisal was performed using the Newcastle-Ottawa scale.

Participants/materials, setting, methods

We included studies where the study population consisted of women with a history of RPL (defined as 2 or more pregnancy losses), where the comparator group consisted of women without a history of RPL, and where the outcomes assessed included PTB (defined as birth prior to 37 completed weeks gestation). Two reviewers independently extracted data in duplicate. Publication date, population, exposure and outcome data were extracted.

Main results and the role of chance

A total of 12 retrospective observational studies met inclusion criteria, and were included in the systematic review and meta-analysis (N = 37,046 women with a history of RPL). Incidence of PTB among the RPL groups ranged from 5.8% to 19.6%, and from 1.5-14.0% in the non-RPL groups. A pooled OR of 1.59 with 95% CI 1.40-1.80 was observed in our random-effects meta-analysis with an I2 of 84%. Subgroup analyses were completed for the pooled risk of only 2 RPL (pooled odds ratio [OR] 1.35; 95% CI 1.08-1.69; I2=84.7%); ≥2 RPL (pooled OR 1.42; 95% CI 0.91-2.22; I2=68.9%); and ≥3 RPL (pooled OR 1.86; 95% CI 1.51-2.29; I2=79.5%).

Limitations, reasons for caution

Inconsistent adjustment for confounders and significant between-study heterogeneity were noted in this study.

Wider implications of the findings

Despite significant heterogeneity among studies, we found that women with a history of RPL had significantly higher odds of delivering preterm infants in their subsequent pregnancies.

Trial registration number

CRD 224763

Energy and nitrogen balance of dairy cattle as affected by provision of different essential amino acid profiles at the same metabolizable protein supply

Amino acid composition of metabolizable protein (MP) is important in dairy cattle diets, but effects of AA imbalances on energy and N utilization are unclear. This study determined the effect of different AA profiles within a constant supplemental MP level on whole-body energy and N partitioning in dairy cattle. Five rumen-fistulated Holstein-Friesian dairy cows (2.8 ± 0.4 lactations; 81 ± 11 d in milk; mean ± standard deviation) were randomly assigned to a 5 × 5 Latin square design in which each experimental period consisted of 5 d of continuous abomasal infusion followed by 2 d of rest. A total mixed ration consisting of 58% corn silage, 16% alfalfa hay, and 26% concentrate (dry matter basis) was formulated to meet 100 and 83% of net energy and MP requirements, respectively, and was fed at 90% of ad libitum intake by individual cow. Abomasal infusion treatments were saline (SAL) or 562 g/d of essential AA delivered in 4 profiles where individual AA content corresponded to their relative content in casein. The profiles were (1) a complete essential amino acid mixture (EAAC), (2) Ile, Leu, and Val (ILV), (3) His, Ile, Leu, Met, Phe, Trp, Val (GR1+ILV), and (4) Arg, His, Lys, Met, Phe, Thr, Trp (GR1+ALT). The experiment was conducted in climate respiration chambers to determine energy and N balance in conjunction with milk production and composition, digestibility, and plasma constituents. Compared with SAL, infusion of EAAC increased milk, protein, and lactose yield, increased energy retained as body protein, and did not affect milk N efficiency. Total N intake and urine N output was higher with all AA infusions relative to SAL. Compared with EAAC, infusions of GR1+ILV and GR1+ALT produced the same milk yield and the same yield and content of milk fat, protein, and lactose, and had similar energy and N retention. Milk N efficiency was not different between EAAC and GR1+ILV, but was lower with GR1+ALT compared with EAAC, and tended to be lower with GR1+ALT compared with GR1+ILV. Infusion of ILV tended to decrease dry matter intake compared with the other AA infusions. Milk production and composition was not different between ILV and SAL. Compared with EAAC, infusion of ILV decreased or tended to decrease milk, protein, and lactose yields and milk protein content, and increased milk fat and lactose content. Milk N efficiency decreased with ILV compared with SAL, EAAC, and GR1+ILV. Milk urea concentration was not affected by essential amino acid (EAA) infusions. Plasma urea concentration did not differ between EAAC and SAL, tended to increase with ILV and GR1+ILV over SAL, and increased with GR1+ALT compared with EAAC and SAL. In conclusion, removing Arg, Lys, and Thr or removing Ile, Leu, and Val from a complete EAA profile when the total amount of EAA infused remained constant did not impair milk production, but milk N efficiency decreased when Ile, Leu, and Val were absent. Infusion of only Ile, Leu, and Val decreased milk protein yield and content and reduced milk N efficiency compared with a complete EAA profile.

Mammary gland metabolite utilization in response to exogenous glucose or long-chain fatty acids at low and high metabolizable protein levels

We investigated mammary gland metabolism in lactating dairy cattle in response to energy from glucogenic (glucose; GG) or lipogenic (palm olein; LG) substrates at low (LMP) and high (HMP) metabolizable protein levels. According to a 6 × 6 Latin square design, 6 rumen-fistulated second-lactation Holstein-Friesian dairy cows (97 ± 13 d in milk) were abomasally infused with saline (LMP-C); isoenergetic infusions (digestible energy basis) of 1,319 g/d glucose (LMP-GG), 676 g/d palm olein (LMP-LG), or 844 g/d essential AA (EAA; HMP-C); or isoenergetic infusions of 1,319 g/d glucose + 844 g/d EAA (HMP-GG) or 676 g/d palm olein + 844 g/d EAA (HMP-LG). Each experimental period consisted of 5 d of continuous infusion followed by 2 d of rest. A total mixed ration (42% corn silage, 31% grass silage, and 27% concentrate on a dry matter basis) formulated to meet 100 and 83% of net energy and metabolizable protein requirements, respectively, was fed at 90% of ad libitum intake by individual cow. Arterial and venous blood samples were collected on d 5 of each period. Infusing GG or LG at the HMP level did not affect milk yield or composition differently than at the LMP level. Neither GG nor LG infusion stimulated milk protein or lactose yield, but fat yield tended to decrease with GG and tended to increase with LG. Infusion of GG increased arterial plasma concentrations of glucose and insulin and decreased concentrations of β-hydroxybutyrate (BHB), nonesterified fatty acids, long-chain fatty acids (LCFA), total AA, EAA, and group 2 AA. Infusion of LG increased arterial triacylglycerides (TAG) and LCFA but did not affect EAA concentrations. Compared with the LMP level, the HMP level increased arterial concentrations of BHB, urea, and all EAA groups and decreased the concentration of total non-EAA. Mammary plasma flow increased with GG and was not affected by LG or protein level. Uptake and clearance of total EAA and group 2 AA were affected or tended to be affected by GG × AA interactions, with their uptakes being lower and their clearances higher with GG, but only at the LMP level. Infusion of LG did not affect uptake or clearance of any AA group. The HMP level increased uptake and decreased clearance of all EAA groups and decreased non-EAA uptake. Infusion of GG tended to increase mammary glucose uptake, and tended to decrease BHB uptake only at the LMP level. Infusion of LG increased mammary uptake of TAG and LCFA and increased or tended to increase clearance of TAG and LCFA. We suspect GG increased mammary plasma flow to maintain intramammary energy and AA balance and stimulated lipogenesis in adipose, accounting for depressed arterial BHB and group 2 AA concentrations. Mammary glucose uptake did not cover estimated requirements for lactose and fat synthesis at the HMP level, except during HMP-GG infusion. Results of this study illustrate flexibility in mammary metabolite utilization when absorptive supply of glucogenic, lipogenic, and aminogenic substrate is increased.

Expression of genes related to energy metabolism and the unfolded protein response in dairy cow mammary cells is affected differently during dietary supplementation with energy from protein and fat

Secretory capacity of bovine mammary glands is enabled by a high number of secretory cells and their ability to use a range of metabolites to produce milk components. We isolated RNA from milk fat to measure expression of genes involved in energy-yielding pathways and the unfolded protein response in mammary glands of lactating cows given supplemental energy from protein (PT) and fat (FT) tested in a 2 × 2 factorial arrangement. We hypothesized that PT and FT would affect expression of genes in the branched-chain AA catabolic pathway and tricarboxylic acid (TCA) cycle based on the different energy types (aminogenic versus lipogenic) used to synthesize milk components. We also hypothesized that the response of genes related to endoplasmic reticulum (ER) homeostasis via the unfolded protein response would reflect the increase in milk production stimulated by PT and FT. Fifty-six multiparous Holstein-Friesian dairy cows were fed a basal total mixed ration (34% grass silage, 33% corn silage, 5% grass hay, and 28% concentrate on a dry matter basis) for a 28-d control period. Experimental rations were then fed for 28 d, consisting of (1) low protein, low fat (LP/LF); (2) high protein, low fat (HP/LF); (3) low protein, high fat (LP/HF); or (4) high protein and high fat (HP/HF). To obtain the high-protein (HP) and high-fat (HF) diets, intake of the basal ration was restricted and supplemented isoenergetically (net energy basis) with 2.0 kg/d rumen-protected protein (soybean + rapeseed, 50:50 mixture on dry matter basis) and 0.68 kg/d hydrogenated palm fatty acids on a dry matter basis. RNA from milk fat samples collected on d 27 of each period underwent real-time quantitative PCR. Energy from protein increased expression of BCAT1 (branched-chain amino acid transferase 1) mRNA, but only at the LF level, and tended to decrease expression of mRNA encoding the main subunit of the branched-chain keto-acid dehydrogenase complex. mRNA expression of malic enzyme, a proposed channeling route for AA though the TCA cycle, was decreased by PT, but only at the LF level. Expression of genes associated with de novo fatty acid synthesis was not affected by PT or FT. Energy from fat had no independent effect on genes related to ER homeostasis. At the LF level, PT activated XBP1 (X-box binding protein 1) mRNA. At the HF level, PT increased mRNA expression of the gene encoding GADD34 (growth arrest and DNA damage-inducible 34). These findings support our hypothesis that mammary cells use aminogenic and lipogenic precursors differently for milk component production when dietary intervention alters AA and fatty acid supply. They also suggest that mammary cells respond to increased AA supply through mechanisms of ER homeostasis, dependent on the presence of FT.

Mammary gland utilization of amino acids and energy metabolites differs when dairy cow rations are isoenergetically supplemented with protein and fat

Mammary gland utilization of AA and other metabolites in response to supplemental energy from protein (PT) and supplemental energy from fat (FT) was tested in a 2 × 2 factorial arrangement using a randomized complete block design. Fifty-six Holstein-Friesian dairy cows were adapted during a 28-d control period to a basal total mixed ration consisting of 34% grass silage, 33% corn silage, 5% grass hay, and 28% concentrate on a dry matter (DM) basis. Experimental rations were fed for 28 d immediately following the control period and consisted of (1) low protein, low fat (LP/LF), (2) high protein, low fat (HP/LF), (3) low protein, high fat (LP/HF), and (4) high protein, high fat (HP/HF). To obtain the high-protein (HP) and high-fat (HF) diets, intake of the basal ration was restricted and supplemented isoenergetically [net energy (MJ/d) basis] with 2.0 kg/d rumen-protected protein (soybean + rapeseed, 50:50 mixture on a DM basis) and 0.68 kg/d hydrogenated palm fatty acids on a DM basis. Arterial and venous blood samples were collected on d 28 of both periods. Isoenergetic supplements (MJ/d) of protein and fat independently and additively increased milk yield, PT increased protein yield, and FT increased fat yield. A PT × FT interaction affected arterial concentration of all essential AA (EAA) groups, where they increased in response to PT by a greater magnitude at the LF level (on average 35%) compared with the HF level (on average 14%). Mammary gland plasma flow was unaffected by PT or FT. Supplementation with PT tended to decrease mammary clearance of total EAA and decreased group 1 AA clearance by 19%. In response to PT, mammary uptake of total EAA and group 2 AA increased 12 and 14%, respectively, with significantly higher uptake of Arg, Ile, and Leu. Energy from fat had no effect on mammary clearance or uptake of any AA group. The mammary gland uptake:milk protein output ratio was not affected by FT, whereas PT increased this ratio for EAA and group 2 AA. Arterial plasma insulin concentration decreased in response to FT, in particular on the HP/HF diet, as indicated by a PT × FT interaction. Arterial concentrations of nonesterified fatty acids, triacylglycerol, and long-chain fatty acids increased in response to FT, and concentrations of β-hydroxybutyrate and acetate decreased in response to FT only at the HP level. Mammary clearance and uptake of triacylglycerol and long-chain fatty acids increased in response to FT. Energy from PT and FT increased lactose yield despite no change in arterial glucose concentration or mammary glucose uptake. Mammary-sequestered glucose with PT or FT was used in the same amount for lactose synthesis, and a positive net mammary glucose balance was found across all treatments. Results presented here illustrate metabolic flexibility of the mammary gland in its use of aminogenic versus lipogenic substrates for milk synthesis.

African born women living with HIV in the United States: unmet needs and opportunities for intervention

Africa born (immigrant) women comprise a disproportionate number of Black women living with HIV in the United States. Though they are at risk for mental health disorders, including psychological distress and depression, little is known about their experience with these important predictors of quality of life, retention in care and adherence to antiretroviral therapy. In this qualitative study, we used constructivist grounded theory to explore the psychosocial and mental health challenges of African born women living with HIV in Boston and New York City. We conducted one-on-one semi-structured interviews with 45 women. Major themes contributing to psychological distress and depressive symptoms included (1) pre-immigration HIV-related stigma; (2) persistent HIV-related stigma post-immigration, (3) undocumented immigration status, (4) economic insecurity, and (5) intimate partner violence (IPV). Many participants described ongoing depressive symptoms or histories of depressive episodes. Yet, most had not been formally diagnosed or treated for depression. Prayer, consultation with faith leadership, and support groups were described most frequently as useful interventions. Future research should explore these thematic areas among a larger, more representative sample of African born women living with HIV to determine differences by country of origin across thematic areas. These data would be useful to inform development of innovative and culturally appropriate interventions.

University of Chicago Consortium phase II study of ispinesib (SB-715992) in patients (pts) with advanced renal cell carcinoma (RCC)

15573

Background: Ispinesib is a novel kinesin spindle protein inhibitor that has significant antitumor activity in multiple tumor models and has demonstrated preliminary clinical activity in early phase I and II trials. A phase II study of Ispenisib in patients with metastatic RCC who had received at least one prior therapy was thus conducted. Methods: The primary objective was to assess the RECIST based overall response rate (RR) with optimal Simon two-stage design utilizing 10% and 30% RR as the null and alternative hypotheses, respectively. Eighteen pts were to be accrued during the first stage; if 3 or more responses (PR or CR) were seen, an additional 17 pts would be accrued. Further study would be recommended if 7 or more of the 35 total pts had a response. Secondary objectives included toxicity, time to progression, and overall survival. Pts were treated with 7 mg/m2 over one hour on days 1, 8, and 15 every 28 days with radiologic disease re- evaluation every 8 weeks. Results: 19 pts were accrued in 6 months. Baseline characteristics included clear cell histology in 74%, papillary in 11%, and unclassified in 11%; 1 or =2 prior therapies in 37% and 63%; prior immunotherapy in 53%, and prior sunitinib, sorafenib or bevacizumab in 79%; ECOG performance status 0 in 58% and 1 in 42%. 4 patients are too early for radiologic assessment. None of the 15 patients evaluable responded to treatment (95% CI: 0 - 21.8%). Seven patients (47%) experienced stable disease after 8 weeks. One patient experienced grade 3 neutropenia. No other grade 3 or 4 toxicities were attributable to drug. Grade 1 and 2 toxicities included: fatigue (28%), anemia (28%), leukopenia (33%), elevated alkaline phosphatase (18%), anorexia (11%), hyponatremia (11%), dyspnea (11%), headache (11%), and hypoalbuminemia (11%). Conclusions: Treatment with weekly Ispenesib in metastatic RCC is well tolerated but does not lead to objective responses. Under the hypothesis that Ispenesib is a cytotoxic rather than cytostatic agent, further evaluation in patients with metastatic RCC at this dose and schedule is not indicated. Supported by: NCI #N01-CM-62201

No significant financial relationships to disclose.

Final analysis of a multi-center, double-blind, placebo-controlled, randomized phase II trial of gemcitabine/cisplatin (GC) plus bevacizumab (B) or placebo (P) in patients (pts) with malignant mesothelioma (MM)

7526

Background: In phase II trials in MM, GC on a 21-day (D) schedule has response rates of 16%–26% and median overall survival (OS) of 9.6–13 months (mo). Since VEGF has a key role in MM biology, we added anti-VEGF antibody B to GC in a multi-center, double- blind, placebo-controlled randomized phase II trial. Methods: Eligible pts had unresectable MM; no prior chemotherapy; PS 0–1; no thrombosis, bleeding, or major vessel invasion. Primary endpoint: progression-free survival (PFS). Statistics: 90% power to detect HR 0.57. Stratification: PS (0/1), histology (epithelial/other). G 1,250 mg/m2 D 1, 8 Q21D, C 75 mg/m2 D1 Q21D, and B 15 mg/kg or P D1 Q21D was given × 6 cycles, then B or P Q21D until progression. Baseline plasma VEGF was measured. 115 pts enrolled 12/01- 07/05 at 11 sites, 108 (GCB/GCP) 53/55 were evaluable. Male 74%/84%; median age 62/65 (range 44–78/20–84); PS 1 55%/47%; epithelial 74%/67%; pleural 93%/91%; thrombocytosis 40%/40%. Results: Cycles: total 458/424, median 7/6, range 1–42/2–39. Statistically significantly different (SSD) toxicity (p <0.05), any grade: alopecia 60%/38%; epistaxis 62%/24%; hypertension 45%/22%; non-neutropenic infection 15%/4%; proteinuria 62%/47%; stomatitis 23%/7%. There were no SSD toxicities = grade 3. Median PFS 6.9/6.0 mo (HR 0.93, p=0.88). Median OS 15.6/14.7 mo (p=0.91). 1-year survival 59%/57%. Partial response 25%/22%; stable disease 51%/60%. Median VEGF (N=56) 131/154 pg/ml (range 31–1760/5–1786). Higher VEGF was associated with shorter PFS (p=0.02) and OS (p=0.0066). In pts with VEGF = the median, PFS (p=0.043) and OS (p=0.028) were significantly greater for GCB than GCP; in high VEGF strata this was not SSD. Conclusion: Adding B to GC in MM pts does not yield statistically significant differences in PFS, OS, response, or grade ¾ toxicity. GCB-treated pts with low VEGF levels had longer PFS and OS. Supported by NCI grant N01-CM-17102.

No significant financial relationships to disclose.

Longevity of Ceratomyxa shasta and Parvicapsula minibicornis actinospore infectivity in the Klamath River

Infectious Ceratomyxa shasta and Parvicapsula minibicornis actinospores were present in Klamath River samples collected in April, May, and June 2005. Juvenile Chinook salmon Oncorhynchus tshawytscha exposed to river water maintained at the ambient Klamath River temperature for 0, 4, 24, 72, and 168 h (7 d) developed asymptomatic infections from both parasites. Elevated water temperature (18 degrees C) in June may have reduced actinospore viability, as both C. shasta and P. minibicornis infection markedly declined in fish exposed for over 72 h. As judged by the prevalence of infection for both parasites, the number of infectious actinospores tended to increase or remain steady through the spring. Ceratomyxa shasta infections were characterized by the presence of a few trophozoites within granulomatous foci in mesentery adipose tissue and were consistently observed outside of the intestine. Similarly, low numbers of P. minibicornis were observed in kidney glomeruli and tubules but were not associated with inflammation. Parvicapsula minibicornis DNA was consistently detected by quantitative real-time polymerase chain reaction in filtered water samples collected each month and from each time posttransfer. These data and the high prevalence of infection observed in the exposed fish indicate that P. minibicornis actinospores were at a relatively high concentration in the river during the spring. In contrast, C. shasta DNA was only detected in half of the water sample sets and its detection did not correspond well to C. shasta infectivity. An approximately threefold increase in river flow from the April to the May water collection was not associated with a decline in either the detection of actinospores (particularly for P. minibicornis) or the prevalence of infection for both parasites. Actinospores of these myxosporean parasites have the potential to infect salmonids for at least 7 d after release from the alternate polychaete host.

Sustained reductions in neonatal nosocomial infection rates following a comprehensive infection control intervention

OBJECTIVE

Nosocomial infections (NI) are a frequent and important cause of morbidity and mortality in newborn infants who receive intensive care. We sought to determine if comprehensive infection control (CIC) measures decrease rates in a large neonatal intensive care nursery.

METHODS

Single center interventional study. The CIC intervention consisted of increasing nursing and physician education and awareness of infection rates, establishing common improvement goals, training in hand and environment care, and implementing a specialty nursing team for central venous and arterial catheter care. Demographic and microbiology information for all infants admitted to the NICU from January 1, 1999 to December 31, 2000 established baseline data. The intervention period was during January and February 2001. The postintervention period was March 1, 2001 to February 29, 2004. The main outcome measure was the rate of blood, cerebrospinal and/or urinary tract bacterial infections per 1000 hospital days.

RESULTS

Baseline infection rate was 8.5 per 1000 hospital days. The NI rate fell 26% (P=0.002) from baseline in the first year and 29% (P<0.001) in the second and third years after the CIC intervention. The reduction in total NI was due mostly to a 46% fall in coagulase-negative Staphylococcus infection rate (P<0.001); however, rates of all other organisms also fell by 21% (P=0.05).

CONCLUSIONS

CIC measures can reduce bacterial and fungal NI rates. This effect has been sustained for 3 years following the intervention.

[Correlation of hematologic parameters with bone marrow and spleen uptake in FDG PET]

OBJECTIVE

To assess the relationship between various hematologic parameters and bone marrow (BM) and splenic uptake of FDG in PET imaging.

MATERIAL AND METHODS

29 patients with Hodgkin's disease (HD) referred for baseline FDG PET imaging before treatment and without evidence of bone marrow (BM) involvement were included in the study. Splenic uptake also was analyzed in 18 patients without splenic involvement. BM and splenic activity were visually graded on a 3 point scale. Activity pattern was classified as homogeneous or heterogeneous. Semi-quantitative analysis was also performed by drawing regions of interest (ROI) over the spine and spleen. ROIs also were drawn over right lung and liver. FDG uptake ratios for the spine and spleen in comparison with the lung and liver were generated. Visual scoring of marrow and splenic uptake, and the various ratios were correlated with hemoglobin (Hb), white blood cell (WBC), and platelet counts, and correlation coefficients were calculated.

RESULTS

In 27/29 patients (93 %) BM and in 18/18 patients (100 %) spleen uptake was diffuse. There was a direct correlation between BM and spleen uptake of FDG with increasing WBC, which was stronger than the inverse correlation seen with Hb (the lower the Hb the greater the uptake). Correlation with platelet counts was weaker.

CONCLUSION

There is a correlation between hematologic parameters such as Hb, WBC and platelet counts and the uptake of FDG in BM and spleen in PET imaging. Knowledge of this correlation should help to better interpret and understand PET imaging.

Gated blood-pool SPECT automated versus manual left ventricular function calculations

Planar gated blood-pool imaging (GBPI) is a standard method for non-invasive assessment of left ventricular (LV) function. Gated blood-pool single photon emission computed tomographic (GBPS) data acquisition can be accomplished in the same time as GBPI, with the benefit of enabling visualization of all cardiac chambers simultaneously. The purpose of this investigation was to evaluate the degree to which automated and manual LVEF calculations agree with one another and with conventional GBPI LVEF measurements. GBPI studies were performed in 22 consecutive, unselected patients, followed by GBPS data acquisition. GBPS left ventricular ejection fraction (LVEF) calculations were performed by available software (NuSMUGA, Northwestern University, Chicago, IL) automatically and manually, using all LV gated short axis slices. Automatic LVEF assessed by GBPS correlated well with conventional planar GBPI (r = 0.88, P < 0.001). Mean planar GBPI LVEF was 50% +/- 12%, and mean GBPS automatic LVEF was significantly lower at 45% + 14% (P = 0.001), with a mean difference of 6% +/- 5%. Manual GBPS LVEF also correlated well with conventional planar GBPI (r = 0.90, P < 0.0001). Mean LVEF measurement by manual GBPS versus GBPI was significantly higher at 59% +/- 13%, with a mean difference of 10% +/- 6% (P < 0.001). Manual GBPS LVEF values were also significantly higher than automatically determined GBPS LVEF values (P < 0.001). It is concluded that LVEF values assessed by NuSMUGA GBPS software were reproducible, and automatic and manual values correlated well with conventional GBPI values. However, both automatic and manual GBPS calculations were significantly different from one another and from GBPI values, so that GBPI and NuSMUGA calculations cannot be considered to be equivalent.

The expression of WT1 in the differentiation of rhabdomyosarcoma from other pediatric small round blue cell tumors

The WT1 gene encodes a transcription factor implicated in normal and neoplastic development. The purpose of this study was to evaluate the diagnostic utility of a commercial WT1 antibody on a variety of pediatric small round blue cell tumors (SRBCT). A mouse monoclonal antibody (clone: 6F-H2, DAKO) raised against the N-terminal amino acids 1-181 of the human WT1 protein was tested. Microscopic sections from 66 specimens were stained using an antigen retrieval protocol with trypsin. The tumors included peripheral neuroectodermal tumors (PNET/Ewing's), neuroblastomas, desmoplastic small round cell tumors (DSRCT), lymphomas, Wilms' tumors, and rhabdomyosarcomas (RMS). One RMS case was investigated by Western blot analysis and RT-PCR to confirm the antibody specificity. A strong cytoplasmic staining was demonstrated in all RMS (11/11). The Western blot analysis confirmed the WT1 protein in the tissue, and the RT-PCR confirmed the presence of WT1 mRNA in the peripheral blood and tissue of one RMS patient. The Wilms' tumors had a variable nuclear and/or cytoplasmic positivity in most (17/24) cases. All PNET/Ewing's were negative. The nuclei of two lymphoblastic lymphomas stained strongly. A weak nuclear or cytoplasmic staining was reported in a few DSRCT (3/5), lymphomas (2/10), and neuroblastomas (2/8). This is a useful antibody in the differentiation of RMS from other SRBCTs. A strong cytoplasmic staining favors an RMS, and a strong nuclear staining is suggestive of a Wilms' tumor. A role for WT1 in the pathogenesis of rhabdomyosarcomas is raised. The limited sampling precludes any conclusions regarding the value of tissue or peripheral blood analysis for WT1 mRNA in patients with rhabdomyosarcoma.

Identification, mapping, and genomic structural analysis of an immunoreceptor tyrosine-based inhibition motif-bearing C-type lectin from homozygous clones of rainbow trout (Oncorhynchus mykiss)

Utilizing a spleen-derived cDNA library and rapid amplification of cDNA 5' ends, we cloned a novel type II C-type lectin from two homozygous clones of rainbow trout. The cDNA is 2535 bp in length, and contains a 1017-bp open reading frame. From this sequence, a protein containing 339 amino acids (aa) was deduced. Using PSI-BLAST to search the GenBank database, the deduced protein is a C-type lectin, belonging to the type II membrane receptors. The protein contains four domains: an 87-aa N-terminal cytoplasmic domain, a 21-aa transmembrane domain, an 82-aa neck domain, and a 149-aa C-terminal C-type lectin domain. Two immunoreceptor tyrosine-based inhibition motifs (ITIMs) were located in the N-terminal cytoplasmic domain. RT-PCR results indicated that this gene is transcribed mainly in peripheral blood lymphocytes, spleen, kidney, and gill, and its expression in liver and intestine is weak. Monoclonal antibody 1.14 was used to isolate B cells from peripheral blood lymphocytes. Analysis revealed that this gene is highly expressed in B cells. Genomic DNA was amplified with long-template PCR and sequenced. The gDNA is 12.0 kb in length and contains nine exons and eight introns. The first intron of the genes from the OSU and AR clones differed in length. Based on this difference, the genotype of 69 doubled-haploid offspring of OSU and AR were screened. Subsequently, this gene was mapped on the rainbow trout linkage map to group XXI. Results of a Southern blot indicated that the gene ( TCL-2) exists as a single copy in the rainbow trout genome. The genomic structure, the deduced protein structure, the tissue expression pattern, as well as the phylogenetic analysis of the carbohydrate recognition domain based on the deduced amino acid sequence indicate that TCL-2 resembles CD72; however, the carbohydrate recognition domain sequences of TCL-2 and CD72 are highly diverged.

Experimental protocols for investigating relationships among mother-infant interaction, affect regulation, physiological markers of stress responsiveness, and attachment

Gergely and Watson's (1996) social biofeedback theory of parental affect mirroring applies the conditional probability model of contingency perception to parent-child interactions. Infants are first evaluated at birth on neurological and temperament measures. Infants are also evaluated at 6 and 12 months on tasks that study social interactional determinants, infant attachment, and physiological reactions. The Strange Situation is completed at 12-15 months of age. The authors describe how the combination of these experimental and observational procedures allows specific developmental hypotheses to be investigated about the quality of contingent parental affect regulation, sensitivity to internal states, and security of attachment.

Clinical impact of arrhythmias on gated SPECT cardiac myocardial perfusion and function assessment

BACKGROUND

We reported previously that mean quantified cardiac functional parameters computed by one gated single photon emission computed tomography (SPECT) technique were not significantly altered by common gating errors. However, it is not known to what extent other gated SPECT approaches that are based on different ventricular modeling assumptions are influenced by arrhythmias, nor are the effects of gating errors on visual analyses and their subsequent clinical implications known.

METHODS

Projection data for 50 patients (aged 64 +/- 12 years; 68% men; 76% with myocardial perfusion defects) undergoing technetium-99m sestamibi gated SPECT who were in sinus rhythm during data acquisition were altered to simulate common arrhythmias. To determine quantitative effects, we performed calculations for original control and altered images by Gaussian myocardial detection (Quantitative Gated SPECT [QGS] program) and by wall thickening derived from gated perfusion polar maps (Emory Cardiac Toolbox program). To evaluate visual assessment in control and simulated-arrhythmia tomograms, 2 experienced blinded observers independently interpreted perfusion from polar maps and wall motion and thickening from tomographic cines, using a 4-point scale.

RESULTS

Although mean functional parameters were scarcely altered, paired t tests showed ejection fraction fluctuations to be significantly different from control values, causing patients to change between abnormal and normal ejection fraction categories (2% of patients by QGS and 14% by Emory Cardiac Toolbox). Visual examination of QGS polar perfusion and function maps showed changes for 72% of cases, although in only 4% were these considered to have potential clinical consequences. The kappa statistic for visual analysis of concordance between control and arrhythmia readings showed that agreement was "excellent" for perfusion, "good" for motion, and "marginal" for thickening.

CONCLUSIONS

As with quantitative measurements, thickening is the parameter most prone to error in the presence of arrhythmias. It is important to test data for gating errors to avoid potentially erroneous measurements and visual readings.

Neural mechanisms underlying migrating motor complex formation in mouse isolated colon

1. Little is known about the intrinsic enteric reflex pathways associated with migrating motor complex (MMC) formation. Acetylcholine (ACh) mediates the rapid component of the MMC, however a non-cholinergic component also exists. The present study investigated the possible role of endogenous tachykinins (TKs) in the formation of colonic MMCs and the relative roles of excitatory and inhibitory pathways. 2. MMCs were recorded from the circular muscle at four sites (proximal, proximal-mid, mid-distal and distal) along the mouse colon using force transducers. 3. The tachykinin (NK(1) and NK(2)) receptor antagonists SR-140 333 (250 nM) and SR-48 968 (250 nM) reduced the amplitude of MMCs at all recording sites, preferentially abolishing the long duration contraction. Residual MMCs were abolished by the subsequent addition of atropine (1 microM). 4. The neuronal nitric oxide synthase inhibitor, N(omega)nitro-L-arginine (L-NOARG, 100 microM), increased MMC amplitude in the distal region, whilst reducing the amplitude in the proximal region. In preparations where MMCs did not migrate to the distal colon, addition of L-NOARG resulted in the formation of MMCs. Subsequent addition of apamin (250 nM) or suramin (100 microM) further increased MMC amplitude in the distal region, whilst suramin increased MMC amplitude in the mid-distal region. Apamin but not suramin reduced MMC amplitude in the proximal region. Subsequent addition of SR-140 333 and SR-48 968 reduced MMC amplitude at all sites. Residual MMCs were abolished by atropine (1 microM). 5. In conclusion, TKs, ACh, nitric oxide (NO) and ATP are involved in the neural mechanisms underlying the formation of MMCs in the mouse colon. Tachykinins mediate the long duration component of the MMC via NK(1) and NK(2) receptors. Inhibitory pathways may be involved in determining whether MMCs are formed.

Development and application of normal limits for left ventricular ejection fraction and volume measurements from 99mTc-sestamibi myocardial perfusion gates SPECT

Gated SPECT is a reproducible method for assessing left ventricular volume (LVV) and left ventricular ejection fraction (LVEF) from 99mTc-sestamibi myocardial perfusion imaging studies. LVV and LVEF measurements by this approach correlate well with those obtained from other cardiovascular imaging techniques. Nevertheless, the lack of criteria for abnormal test findings has limited the potential clinical application of this new imaging technique.

METHODS

Gated SPECT measurements were evaluated for 214 patients with a low Bayesian likelihood (< 10%) of coronary artery disease (CAD) before performance of 99mTc-sestamibi stress-rest myocardial perfusion SPECT. The patients were grouped into normotensive patients (n = 98), hypertensive patients without left ventricular hypertrophy (LVH) (n = 80), and hypertensive patients with LVH on resting electrocardiography (n = 36). Gated SPECT measurements for left ventricular end-diastolic volume (LVEDV) index, left ventricular end-systolic volume (LVESV) index, and LVEF were obtained according to a published method, using a modified Simpson's rule technique.

RESULTS

Similar results were obtained for mean LVV and LVEF measurements between normotensive patients and hypertensive patients without LVH. Hence, these groups were combined (as group 1). By contrast, hypertensive patients with LVH (group 2), had significantly lower LVEF values (P = 0.01) and higher mean LVESV index values than normotensive patients (P = 0.03). Sex differences were marked: women had significantly higher mean resting LVEF values than men (P < 0.0001) and significantly lower mean resting LVEDV index values (P < 0.0001). A significant relationship was seen between LVEDV index and LVEF (r = -0.60; P < 0.0001) and between LVEDV index and heart rate (r = -0.26; P < 0.001). The normal limits were LVEF > or = 41% in men and > or = 49% in women, LVEDV index < or = 76 mL/m2 in men and < or = 57 mL/m2 in women, and LVESV index < or 38 mL/m2 in men and < or =26 mL/m2 in women. Among hypertensive patients, 22% with LVH had an abnormally low LVEF and 19% had an increased LVEDV index according to these test criteria. By contrast, no hypertensive patients without LVH had an abnormally low LVEF, and only 6% had volume abnormalities.

CONCLUSION

Using a cohort of low-likelihood patients, we generated sex-specific normal limits for LVV and LVEF for myocardial perfusion gated SPECT. Application of these findings resulted in the detection of occult left ventricular dysfunction in approximately one fifth of hypertensive patients for whom concomitant LVH was found through resting electrocardiography. These normal limits can now be evaluated prospectively for their potential clinical value.

Echocardiographic validation of gated SPECT ventricular function measurements

Left ventricular (LV) volumes are valuable prognostic indicators in the management of coronary artery disease and traditionally have been obtained by x-ray contrast angiography or echocardiography. There now are several scintigraphic methods to compute volumes that are based on different LV modeling assumptions. Both the reasons that calculations from different nuclear techniques can disagree with one another and the relationship of these values to the more conventional echocardiographic measurements must be investigated thoroughly for calculations to be interpretable for individual patients.

METHODS

Echocardiographic volumes were determined in 33 retrospective subjects with coronary artery disease (mean age, 61 +/- 12 y; 42% men; 70% with abnormal perfusion and 58% with abnormal segmental wall motion) using the modified Simpson's rule technique applied to digitized apical 4-chamber and apical 2-chamber views of 4 averaged heartbeats. These volumes were compared with those from 3 gated SPECT methods based on Simpson's rule LV modeling similar to standard echocardiographic algorithms (SPECT EF from St. Luke's-Roosevelt Hospital) (method 1), Gaussian myocardial count profile curve fitting (QGS from Cedars-Sinai Medical Center) (method 2), and an endocardial model based on perfusion sampling and count-based thickening (Cardiac Toolbox from Emory University) (method 3).

RESULTS

By ANOVA, there were no significant differences among ejection fractions (EFs), but there were for volumes. Paired t test analysis showed volumes from methods 2 and 3 to be significantly larger than echocardiographic volumes and larger than those of method 1. Linear regression analysis comparing gated SPECT and echocardiographic volumes showed a nearly identical strong correlation (r = 0.92; P < 0.000001) for all 3 methods. Excellent correlation also was found among gated SPECT volumes from the 3 methods (r = 0.94). Bland-Altman analysis and t tests showed that method 1 volumes (70 +/- 61 mL) were the same as for echocardiography (77 +/- 55 mL), but volumes were overestimated by method 2 (105 +/- 74 mL) and method 3 (127 +/- 92 mL), particularly for larger volumes. Pearson coefficients for EFs compared with echocardiography were r = 0.82, 0.75, and 0.72 for methods 1-3, respectively. EFs correlated strongly among the 3 gated SPECT methods (r = 0.86-0.92). The Fisher z test showed no differences among these methods for any of the volume or EF linear correlation analyses.

CONCLUSION

All gated SPECT parameters correlated well with echocardiographic values. However, the gated SPECT method for which underlying assumptions most closely resembled those commonly used in echocardiography produced mean volume values closest in agreement with echocardiographic measurements.

Hospice patient advocacy through complete documentation

The hospice movement was built around patient choice and autonomy. Because of recent Medicare scrutiny, some patients are being denied the choice of hospice at the end of their lives. Hospice staff must learn how to accurately and completely document the care they provide so that patients are not denied access to care because they do not "meet the guidelines" or payment is denied as a result of inadequate or unclear documentation.

Familial clustering of Langerhans cell histiocytosis

Langerhans cell histiocytosis (LCH) is considered a non-hereditary disorder. Evaluation of the few familial cases might provide insight into its aetiology and pathogenesis. We conducted a survey to identify familial LCH cases. Data on family history, zygosity assessment in twins, clinical and laboratory features, treatment outcome, and present status were collected. According to variable confidence for twins monozygosity assessment, we termed these pairs 'presumed monozygotic' (pMZ). Nine families had more than one affected relative: five with LCH-concordant twin pairs, four with LCH in siblings or cousins. Three twin pairs not concordant for LCH were also studied. Overall, four of five pMZ twin pairs and one of three dizygotic (DZ) pairs were concordant for LCH. The pMZ twins had simultaneous and early disease onset (mean age 5.4 months); onset was at 21 months in the DZ pair. Clinical features were similar in the pMZ pairs. One pair of DZ twins had disseminated LCH. The three healthy twins (one pMZ, two DZ) remain asymptomatic 0.3, 5.9 and 4.7 years, respectively, after disease onset in their co-twins. Of the two families with affected non-twin siblings, one had known parental consanguinity and the other possible consanguinity. Potential consanguinity was also present in one of the two families with affected first cousins. Our data support high LCH concordance rates in pMZ twins and add the finding of LCH concordance in one of three dizygotic pairs studied. Taken together with our identification of LCH in siblings and first cousins from known or possibly consanguineous families, and with prior reports of three affected parent-child pairs, the data support a role for genetic factor(s) in LCH. The work-up of newly diagnosed patients should include a careful, extensive family history and chromosome studies. When possible, constitutional and/or lesional DNA should be obtained for future study.

Comparative performance of gated perfusion SPECT wall thickening, delayed thallium uptake, and F-18 fluorodeoxyglucose SPECT in detecting myocardial viability

To evaluate the comparative abilities of gated single photon emission computed tomography (SPECT) wall thickening, delayed thallium-201 (Tl-201) SPECT, and F-18 fluorodeoxyglucose (FDG) SPECT in detecting myocardial viability, 23 patients with previous myocardial infarction and clinically suspected viability were studied. Each patient had at least 1 extensive fixed perfusion defect on rest/stress technetium-99m sestamibi SPECT. A total of 41 major vascular territories had fixed defects. The mean (+/- 1 SD) left ventricular ejection fraction determined from gated perfusion SPECT was 26% +/- 11%. Wall thickening was assessed in a semiquantitative fashion by the regional increase in myocardial intensity during systole and was considered normal when a > or = 20% increase was observed. Tl-201 SPECT was acquired 4 hours after resting tracer injection was administered. Viability was considered present when regional defect Tl-201 count density, determined by quantitative analysis, was > 20% greater than that on the resting sestamibi scan. FDG SPECT was performed independently with a 10 mCi F-18 FDG dose after oral glucose loading was performed. A camera equipped with ultrahigh energy collimation was used. Quantitative criteria for viability were the same as for Tl-201. In the 23 patients viability within the fixed sestamibi defects was manifest by preserved wall thickening in 8 patients, delayed Tl-201 uptake in 10 patients, and FDG uptake in 18 patients. Nine major vascular territories with fixed defects were judged viable by wall thickening, 11 by Tl-201 SPECT, and 24 by FDG SPECT (P = .0009). We conclude that FDG SPECT demonstrates more evidence of myocardial viability than either gated sestamibi wall thickening or delayed Tl-201 SPECT.

Influence of arrhythmias on gated SPECT myocardial perfusion and function quantification

Despite the importance of R-wave gating myocardial perfusion tomography for ventricular function assessment, neither prevalence of gating errors nor their influence on quantified cardiac parameters has been studied.

METHODS

Arrhythmia-induced anomalies in curves of counts versus projection angle for each R-wave segment were detected visually and algorithmically. Arrhythmia prevalence was tabulated for 379 patients (group 1) with prospective coronary artery disease (mean age 63+/-13 y, 47% male). Myocardial counts were analyzed from all reconstructed cinematic midventricular slices to assess arrhythmia effects on percentage of systolic count increase, generally assumed to equal percentage of wall thickening. In a separate retrospective analysis of 41 patients (group 2), with coronary artery disease (mean age 64+/-12 y, 68% male) having no significant arrhythmias, 36 of whom also underwent equilibrium radionuclide angiography, original projection data were altered to simulate arrhythmia-induced aberrant count patterns to evaluate effects on ventricular function and perfusion measurements.

RESULTS

Group 1 patients consisted of 26% without gating errors, 32% with count losses only in the last R-wave interval due to inconsistent transient increase of heart rate, 24% with count decreases in several late intervals due to consistently variable rates, 8% with early interval count increases paired with late interval count decreases due to ectopic beats and 9% with erratic count changes due to atrial fibrillation. Observed count patterns were strongly associated (P < 10(-3)) with arrhythmias detected by electrocardiogram monitoring. In group 2 simulations, ventricular volumes changed by only 2%+/-9% and ejection fraction (EF) by only 1%+/-4% from control values and correlated linearly (r> or = 0.96) with control values for all simulated arrhythmias. SPECT and equilibrium radionuclide angiography EFs correlated similarly (r = 0.85-0.89) for control and all simulations. Percentage changes from control in perfusion defect extent and severity were larger than processing reproducibility limits, the largest change being for atrial fibrillation. Control wall thickening was 38%+/-17%, significantly lower (P < 10(-6)) than for simulated arrhythmias, reflecting similar observations for group 1 patients.

CONCLUSION

Even though ventricular volumes and EFs were affected minimally by arrhythmias, both perfusion analysis and wall thickening were compromised. Consequently, quality assurance of gating may be critically important for obtaining accurate quantified parameters.

Comparison of Tc-99m sestamibi and Tl-201 gated perfusion SPECT

BACKGROUND

To determine the interpretability of gated thallium-201 perfusion SPECT compared with that performed by use of technetium-99m sestamibi (MIBI), 33 patients with prior myocardial infarction were studied. Patients received 22 to 30 mCi (814 to 1110 MBq) MIBI at peak stress, and a 15-minute gated SPECT acquisition was begun 30 to 40 minutes thereafter. On a subsequent day gated Tl-201 SPECT was acquired for 15 minutes, 4 hours after a resting 3.5 mCi (130 MBq) injection. SPECT was performed over a 180-degree arc by use of a 90-degree angled 2-detector camera.

RESULTS

Gated studies were interpreted independently by 4 experienced physicians. Study quality was graded (0 = uninterpretable to 4 = excellent). Wall motion (0 = normal to 2 = akinetic/dyskinetic) and wall thickening (0 = normal to 2 = absent) were graded for each of 10 segments viewed in orthogonal planes. Left ventricular ejection fraction (LVEF) was calculated by use of software thus far validated only for MIBI. The average count density of mid-ventricular end-diastolic short axis tomograms with sestamibi was 3.47 times greater than with thallium. Mean study quality was 3.4 for MIBI and 1.8 for thallium (P < 10(-6)). No gated MIBI SPECTs, but 2 gated thallium studies (6%) were judged uninterpretable. Among interpretable scans, interobserver agreement (Kendall statistic) in assessing wall motion was 0.73 for MIBI and 0.66 for thallium (P = .01). For assessing wall thickening, the Kendall statistic was 0.73 for MIBI and 0.69 for thallium (P = .05). Correlation (r) of LVEFs was 0.91, SEE = 6.4.

CONCLUSIONS

We conclude that gated thallium SPECT is inferior to MIBI because of much poorer image quality and somewhat poorer interobserver agreement among experienced physicians. However, LVEF can be determined reliably from gated thallium SPECT.

Do patient data ever exceed the partial volume limit in gated SPECT studies?

BACKGROUND

Some single photon emission computed tomography (SPECT) methods to detect percent myocardial wall thickening (%WT) assume a linear relationship to changes in maximum myocardial counts, predicated on myocardial walls never exceeding the SPECT camera's partial volume limit. Recent studies have challenged such assumptions, reporting that systolic count changes underestimate wall thickening as measured by echocardiography and magnetic resonance imaging.

METHODS AND RESULTS

To test whether clinical data ever are observed to exceed the partial volume limit, we examined gated tomograms of 75 patients selected at random and of an additional 25 patients known to have hypertension with electrocardiographic evidence of left ventricular hypertrophy. Image transformations were performed such that for every cinematic frame, radial counts at every angle were automatically normalized to the same maximum count. If no patient's myocardium ever exceeded the partial volume limit, thickness quantified from transformed images would always be the same throughout the cardiac cycle and would just correspond to the camera's line spread function. Thickness was measured by Gaussian fitting of transformed myocardial counts in the epicardial direction only to exclude cavitary count contamination. % WT was computed from thickness differences from diastole to systole. % WT values were assessed from clinical data at lateral, inferior, septal, anterior, and apical territories. Resulting %WT distributions were tested against the null hypothesis of %WT = 0 by the Z-test. Although some distributions were not actually Gaussian, the maximum mean %WT was only +3% +/-5% for the septal wall, in agreement with an observer's impressions of no detectable wall thickening. Thus mean %WT values were trivial compared with expected physiologic normal values of 30% to 50%.

CONCLUSION

No convincing evidence was found of thickness above the partial volume limit in this large sample of 75 normotensive and 25 hypertensive patients. Therefore it is likely that relations between myocardial count increases and wall thickening are similar throughout the cardiac cycle, even in patients with left ventricular hypertrophy.

Reliability of enhanced gated SPECT in assessing wall motion of severely hypoperfused myocardium: echocardiographic validation

BACKGROUND

A method has been described for improving myocardial visibility on 99mTc-labeled sestamibi gated tomograms, even in the presence of severe hypoperfusion. It is essential to verify that images transformed in this manner truly depict the myocardium and do not contain image artifacts. This is especially important if transformed images are to be used to aid in the discernment of regional wall-motion abnormalities.

METHODS AND RESULTS

All radially detected maximum counts were mapped automatically to the same brightness level for each cinematic frame. This produced tomographic cine images strongly suggestive of myocardium that appeared to translate but not to brighten from diastole to systole. Transformed scintigrams were compared with echocardiographic cine images of horizontal long axis and short axis views for 40 patients. Echocardiograms were of sufficient quality to allow comparison of radial distances from left ventricular center to midmyocardium for 15 short axis images and 25 horizontal long axis images. Readings were graded independently for 10 territories on a five-point scale (normal, mild-to-moderate hypokinesis, severe hypokinesis, akinesis, dyskinesis) of regional wall motion of original and enhanced scintigrams and echocardiograms. Comparison of echocardiographic and single photon emission computed tomographic (SPECT) locations of midmyocardial horizontal long axis points yielded a root-mean-square error value of 1.5+/-0.6 pixels (average absolute error, 11%+/-5%). SPECT versus echocardiographic wall-motion readings were compared by means of contingency table analysis. The log-likelihood ratio (G2) was 109.3 (n = 364; df = 16) with probability of no association <10(-6). Although readings of unenhanced SPECT cine images agreed well with those of echocardiograms (G2 = 94.3; n = 350; df = 16; P < 10(-6), Pearson-corrected contingency coefficients indicated stronger association with echocardiograms of transformed tomograms than with readings of original scintigrams (0.57 versus 0.51). The McNemar chi2 test indicated this improvement to be significant. The strongest associations were found between readings of unenhanced and enhanced scintigrams. Overall, similar results were obtained for horizontal long axis and short axis territories when analyzed separately. Linear regression analysis indicated strong correlations (r = .80 to r = .92) of ejection fractions from unenhanced gated SPECT images, enhanced gated SPECT images, echocardiograms, and first-pass radionuclide angiograms with no significant differences among correlations.

CONCLUSIONS

Regional image enhancement succeeded in revealing shapes that genuinely represented myocardium in this population with hypoperfusion. Wall-motion conclusions were similar whether drawn from original or enhanced scintigrams, although enhancement significantly improved agreement with echocardiographic readings. Enhanced SPECT cine images allowed sensitive discrimination of regional wall-motion abnormalities, even in areas of severely hypoperfused myocardium, in excellent agreement with visual echocardiographic assessment for which myocardial visualization is independent of perfusion.

Effective sunscreen ingredients and cutaneous irritation in patients with rosacea

Patients with rosacea are particularly susceptible to the irritation caused by sunscreen ingredients. The purpose of this bilateral comparison study was to examine the effects of different ingredients found in sunscreen on facial cutaneous irritancy in patients with rosacea. patients clinically diagnosed with rosacea were asked to test different preparations of common sunscreens on their faces. The results show that the presence or absence of appropriate protective ingredients, such as dimethicone and cyclomethicone in the vehicle, may prevent irritation from other sunscreen ingredients in patients with inflammatory conditions such as rosacea.