Patterns of milking unit kick-off as a proxy for habituation to milking in primiparous cows

The onset of lactation and the subsequent habituation to the milking routine is a stressful period, particularly for primiparous (PRI) cows. The objective of this study was to describe the dynamics of milking unit kick-off (KO) behavior in PRI cows during the first 3 mo of lactation, considering multiparous (MUL) cows as a reference for comparison. In addition, the potential associations between KO and milk yield and mastitis presentation were investigated. A total of 869 cows (PRI = 199; MUL = 670) on a dairy farm in northern CO were included in the analysis. Cows calving between August and November 2020 were enrolled from 3 DIM until 90 DIM. Participants were milked 3×/day in a 60-unit rotary parlor and data from each milking session were downloaded from parlor management software. Milking unit kick-off was used as a proxy for habituation to the milking procedure. Kick-off events were reported by the milking system and defined as an abrupt interruption in the milk flow during the milking process. Cow KO events were recorded for each milking session. Subsequently, occurrence of KO was analyzed by grouping the 3 consecutive milking sessions in each day and categorized as yes or no, indicating whether or not an individual kicked at least once in a given day. Data were analyzed by repeated measures ANOVA and logistic regression, including parity category, calving season, occurrence of dystocia, and their potential interactions in the models. Least squares means for daily proportions of KO were calculated considering the number of cows with KO events per day in the PRI and MUL categories. Subsequently, odds ratios for the occurrence of KO in PRI versus MUL were calculated at multiple periods of time. When KO was analyzed by DIM, proportions of KO were greater in PRI than in MUL during the whole monitoring period. In PRI, proportions of KO increased from 0.10/d to 0.20/d between 3 DIM and 15 DIM, to start decreasing around 30 DIM and remaining above MUL up to 90 DIM. On the contrary, in MUL cows, proportions of KO remained close to 0.05/d during the 90-d period. Overall, the odds of KO were greater for PRI versus MUL cows (odds ratio [95% confidence interval] = 2.07 [1.58-2.73]). No differences in milk yield were established among KO categories, while the percentage of cows affected with mastitis was greater in cows grouped in the quartile with more frequent KO events. We concluded that the relationship between days in milk and the proportion of PRI cows displaying KO was not linear, but rather KO increased during the first 2 wk postpartum before decreasing after the first month of lactation. First-parity cows had greater levels of KO than MUL cows, which is most likely associated with the process of habituation to milking during their first lactation.

Childhood-Onset Lupus Nephritis in the Childhood Arthritis and Rheumatology Research Alliance Registry: Short-Term Kidney Status and Variation in Care

OBJECTIVE

The goal was to characterize short-term kidney status and describe variation in early care utilization in a multicenter cohort of patients with childhood-onset systemic lupus erythematosus (cSLE) and nephritis.

METHODS

We analyzed previously collected prospective data from North American patients with cSLE with kidney biopsy-proven nephritis enrolled in the Childhood Arthritis and Rheumatology Research Alliance (CARRA) Registry from March 2017 through December 2019. We determined the proportion of patients with abnormal kidney status at the most recent registry visit and applied generalized linear mixed models to identify associated factors. We also calculated frequency of medication use, both during induction and ever recorded.

RESULTS

We identified 222 patients with kidney biopsy-proven nephritis, with 64% class III/IV nephritis on initial biopsy. At the most recent registry visit at median (interquartile range) of 17 (8-29) months from initial kidney biopsy, 58 of 106 patients (55%) with available data had abnormal kidney status. This finding was associated with male sex (odds ratio [OR] 3.88, 95% confidence interval [95% CI] 1.21-12.46) and age at cSLE diagnosis (OR 1.23, 95% CI 1.01-1.49). Patients with class IV nephritis were more likely than class III to receive cyclophosphamide and rituximab during induction. There was substantial variation in mycophenolate, cyclophosphamide, and rituximab ever use patterns across rheumatology centers.

CONCLUSION

In this cohort with predominately class III/IV nephritis, male sex and older age at cSLE diagnosis were associated with abnormal short-term kidney status. We also observed substantial variation in contemporary medication use for pediatric lupus nephritis between pediatric rheumatology centers. Additional studies are needed to better understand the impact of this variation on long-term kidney outcomes.

Intraarticular steroids as DMARD-sparing agents for juvenile idiopathic arthritis flares: Analysis of the Childhood Arthritis and Rheumatology Research Alliance Registry

BACKGROUND

Children with juvenile idiopathic arthritis (JIA) who achieve a drug free remission often experience a flare of their disease requiring either intraarticular steroids (IAS) or systemic treatment with disease modifying anti-rheumatic drugs (DMARDs). IAS offer an opportunity to recapture disease control and avoid exposure to side effects from systemic immunosuppression. We examined a cohort of patients treated with IAS after drug free remission and report the probability of restarting systemic treatment within 12 months.

METHODS

We analyzed a cohort of patients from the Childhood Arthritis and Rheumatology Research Alliance (CARRA) Registry who received IAS for a flare after a period of drug free remission. Historical factors and clinical characteristics and of the patients including data obtained at the time of treatment were analyzed.

RESULTS

We identified 46 patients who met the inclusion criteria. Of those with follow up data available 49% had restarted systemic treatment 6 months after IAS injection and 70% had restarted systemic treatment at 12 months. The proportion of patients with prior use of a biologic DMARD was the only factor that differed between patients who restarted systemic treatment those who did not, both at 6 months (79% vs 35%, p < 0.01) and 12 months (81% vs 33%, p < 0.05).

CONCLUSION

While IAS are an option for all patients who flare after drug free remission, it may not prevent the need to restart systemic treatment. Prior use of a biologic DMARD may predict lack of success for IAS. Those who previously received methotrexate only, on the other hand, are excellent candidates for IAS.

Social determinants of health influence disease activity and functional disability in Polyarticular Juvenile Idiopathic Arthritis

BACKGROUND

Social determinants of health (SDH) greatly influence outcomes during the first year of treatment in rheumatoid arthritis, a disease similar to polyarticular juvenile idiopathic arthritis (pJIA). We investigated the correlation of community poverty level and other SDH with the persistence of moderate to severe disease activity and functional disability over the first year of treatment in pJIA patients enrolled in the Childhood Arthritis and Rheumatology Research Alliance Registry.

METHODS

In this cohort study, unadjusted and adjusted generalized linear mixed effects models analyzed the effect of community poverty and other SDH on disease activity, using the clinical Juvenile Arthritis Disease Activity Score-10, and disability, using the Child Health Assessment Questionnaire, measured at baseline, 6, and 12 months.

RESULTS

One thousand six hundred eighty-four patients were identified. High community poverty (≥20% living below the federal poverty level) was associated with increased odds of functional disability (OR 1.82, 95% CI 1.28-2.60) but was not statistically significant after adjustment (aOR 1.23, 95% CI 0.81-1.86) and was not associated with increased disease activity. Non-white race/ethnicity was associated with higher disease activity (aOR 2.48, 95% CI: 1.41-4.36). Lower self-reported household income was associated with higher disease activity and persistent functional disability. Public insurance (aOR 1.56, 95% CI 1.06-2.29) and low family education (aOR 1.89, 95% CI 1.14-3.12) was associated with persistent functional disability.

CONCLUSION

High community poverty level was associated with persistent functional disability in unadjusted analysis but not with persistent moderate to high disease activity. Race/ethnicity and other SDH were associated with persistent disease activity and functional disability.

Administration of acetylsalicylic acid after parturition in lactating dairy cows under certified organic management: Part I. Milk yield, milk components, activity patterns, fertility, and health

Parturition is a natural process that gradually progresses from one stage to the next. However, around 5% of dairy cows will experience dystocia, which is considered to be a painful and stressful event. Studies have reported positive effects on cow performance and welfare after treatment with nonsteroidal anti-inflammatory drugs during the first postpartum days. The objectives were to assess the effects of acetylsalicylic acid administration after calving on (1) milk yield and components, (2) daily activity patterns, (3) reproductive performance, and (4) health in lactating dairy cows under certified organic management. Cows from 3 organic herds were enrolled. Within 12 h after parturition, cows were blocked by parity and calving ease and randomly assigned to 2 treatments: (1) aspirin (ASP; n = 278), in which cows received 4 consecutive treatments every 12 h with acetylsalicylic acid (100 mg/kg; 2 boluses) or (2) placebo (PLC, n = 285), in which cows received 4 treatments every 12 h with gelatin capsules (2 capsules) filled with water. Daily milk yield for the first 30 d in milk (DIM) and monthly milk yield, fat, protein, and somatic cell count (SCC) data from the first 5 Dairy Herd Improvement Association tests were collected. Activity patterns were measured using activity data loggers in the first 7 DIM. Clinical disease events (60 DIM) and fertility data were collected from on-farm computer records. Statistical analysis was performed using the MIXED (milk yield, components, and activity), LIFETEST (fertility), and GLIMMIX (health) procedures of SAS (SAS Institute Inc., Cary, NC). Overall, ASP cows produced 1.82 kg/d more milk than PLC cows during the first 30 DIM. Interestingly, cows that experienced dystocia and received ASP produced 4.48 kg/d more milk compared with cows in the PLC group that experienced dystocia. Cows treated with ASP had lower somatic cell count during the first 5 Dairy Herd Improvement Association tests. There were no differences in daily lying time, lying bouts, and lying bout duration between the ASP and PLC groups. However, cows in the ASP group had 587,64 steps/d more compared with PLC cows. In addition, ASP cows tended to require fewer days (ASP = 113.76 ± 4.99 d; PLC = 125.36 ± 4.74 d) and needed fewer services (ASP = 1.86 ± 0.21 services; PLC = 2.19 ± 0.24 services) to become pregnant compared with PLC cows. There were no differences in clinical disease events between treatments. Results from this study suggest that treating cows with ASP after calving may help improve milk yields and udder health, increase activity, and enhance fertility in dairy cattle under certified organic management.

Administration of acetylsalicylic acid after parturition in lactating dairy cows under certified organic management: Part II. Biomarkers of nociception, inflammation, and stress

The objective was to assess the effect of oral administration of acetylsalicylic acid after calving on the concentrations of substance P (SP), haptoglobin (HP), and cortisol in lactating dairy cows. Holstein dairy cows (n = 152) from 3 organic herds were included. At parturition, cows were blocked by parity [multiparous (MULT) and primiparous (PRIM)] and calving ease [eutocia (EUT) and dystocia (DYS)] and were randomly assigned to 1 of 2 treatment groups: aspirin (ASP; n = 76), in which within 12 h after parturition cows received 4 treatments with acetylsalicylic acid (100 mg/kg; 2 boluses) at 12-h intervals, or placebo (PLC; n = 76), in which within 12 h after parturition cows received 4 consecutive treatments with gelatin capsules (2 capsules) containing water 12 h apart. Blood samples were collected immediately before treatment and at 12, 24, 36, 48, and 168 h (7 DIM) for assessment of circulating concentration of SP, HP, and cortisol. Based on farm records, cows were classified in the following clinical disease categories: no clinical disease event (NO-EVT), a single clinical disease event (SI-EVT), and more than 1 clinical disease event (MU-EVT). The study data were analyzed as a randomized complete block design using mixed multiple linear and logistic regression models. With regard to HP, there was a tendency for an interaction between treatment and parity, where MULT cows treated with ASP had lower concentration of HP compared with MULT cows treated with PLC (ASP = 124.33 ± 6.83 µg/mL; PLC = 143.9 ± 7.24 µg/mL). Analysis by calving ease showed that cows with DYS had higher concentrations of HP (DYS = 159.17 ± 5.97 µg/mL; EUT = 138.72 ± 6.22 µg/mL) and SP (only at 168 h; DYS = 64.99 pg/mL, 95% confidence interval, CI: 2.68-2.81; EUT = 60.33 pg/mL, 95% CI: 2.91-3.06) after calving compared with EUT cows. Regardless of treatment, PRIM cows had higher concentrations of SP (MULT = 55.11 pg/mL, 95% CI: 1.27-1.30; PRIM = 57.62 pg/mL, 95% CI: 1.99-2.06), HP (MULT = 134.14 ± 4.96 µg/mL; PRIM = 163.75 ± 7.76 µg/mL), and cortisol (MULT = 18.65 µg/mL, 95% CI: 1.02-1.05; PRIM = 21.92 µg/mL, 95% CI: 1.67-1.74) compared with MULT cows. In addition, cows that experienced SI-EVT or MU-EVT had higher concentrations of HP (NO-EVT = 134.13 ± 5.95 µg/mL; SI-EVT = 142.68 ± 7.32 µg/mL; MU-EVT = 170.03 ± 9.42 µg/mL) and cortisol (NO-EVT = 17.86 µg/mL, 95% CI: 1.20-1.24; SI-EVT = 21.01 µg/mL, 95% CI: 1.61-1.67; MU-EVT = 22.01 µg/mL, 95% CI: 2.08-2.18) compared with cows with NO-EVT recorded. Results from this study suggest that a short-duration anti-inflammatory therapy after calving reduced HP in MULT cows but may not have effects on SP and cortisol concentrations. Calving ease and parity affected the concentrations of markers of inflammation, nociception, and stress regardless of treatment. Further research is warranted to assess anti-inflammatory strategies aimed at decreasing inflammation and stress in DYS and PRIM cows and therefore improve welfare and performance of these high-priority groups.

Incidence and risk factors for reproductive disorders in organic certified dairies

The objective was to determine the lactational incidence risks of reproductive disorders (RD) including dystocia (DYS), retained fetal membranes (RFM), puerperal metritis (PM), clinical endometritis (CE), pyometra (PYO), late pregnancy loss (LPL), and culling due to reproductive reasons (CRR) in large organic certified dairies with predominant use of Holstein genetics. In addition, potential risk factors for RD, including parity category, milk yield in the previous lactation, season of dry-off, access to grazing at dry-off, length of the dry period (DPL), length of the close-up period (CUPL), calculated gestation length (CGL), season of calving, access to grazing at calving, concurrent health conditions, and total number of artificial inseminations were analyzed. A retrospective study was performed using information from 8 organic certified herds located in northern Colorado and west Texas, ranging from 900 to 6,000 milking cows. Cow information consisted of finalized lactations starting with calvings occurring between January 1, 2016, and December 31, 2018. Data were analyzed using time-to-event analyses and multivariable logistic regression. Clinical endometritis had the greatest lactational incidence risk (incidence risk = 10.1%; 95% CI = 9.8-10.3%), followed by DYS (8.8%; 8.5-9.1%), PM (4.9%; 4.7-5.1%), PYO (4.0%; 3.8-4.1%), LPL (3.6%; 3.4-3.7%), and RFM (2.0%; 1.8-2.1%). The incidence risk of CRR was 7.5% (7.3-8.7%), representing 29.1% (28.4-30.0%) of all culling reasons. Median time from calving to diagnosis of PM, CE, PYO, and LPL were 6, 23, 111, and 228 d, respectively. Median time for CRR was 391 d. The main risk factors for RD were DPL, CGL, and CUPL. Season of dry-off was a risk factor for RFM, PM, CE, LPL, and PYO. Short DPL (<30 d) was associated with increased odds (95% CI) of RFM [2.1 (1.6-2.7)], PM [1.4 (1.2-1.7)], and LPL [2.5 (1.5-4.2)]. Shortened CGL (<270 d) increased the odds of DYS [1.5 (1.3-1.8)], RFM [3.2 (2.4-4.1)], and PM [2.4 (1.7-3.3)], whereas extended CGL (>285 d) increased the odds of DYS [1.5 (1.4-1.7)], PM [1.5 (1.2-2.0)], CE [1.5 (1.1-2.0)], and CRR [1.2 (1.10-1.4)]. Shortened CUPL was associated with increased odds of all the RD. Cows spending less than 7 d in the close-up groups had greater odds of DYS [1.4 (1.1-1.8)], RFM [2.1 (1.8-2.4)], PM [1.9 (1.6-2.1)], PYO [1.5 (1.2-1.8)], LPL [2 (1.7-2.3)], and CRR [1.4 (1.04-1.8)] compared with cows spending more than 14 d in the close-up group. Season of calving was associated with the odds of PM [summer = 1.13 (1.01-1.2)], PYO [summer = 1.7 (1.1-2.5)], and LPL ([fall = 0.8 (0.6-0.96)] compared with winter calving. Other risk factors affecting RD were parity number, total number of artificial inseminations, and concurrent health conditions. Overall, lactational incidence risks of reproductive diseases were comparable with those reported in conventional herds. The identified risk factors for RD open opportunities for interventions, especially focused in precalving management, estimation of due dates, and closer monitoring of pregnancies from natural services in large organic certified dairy herds.

A randomized controlled clinical trial on the effect of acupuncture therapy in dairy cows affected by pyometra

Pyometra (PYO) is a reproductive disease characterized by the accumulation of purulent or mucopurulent material within the uterine lumen, in the presence of an active corpus luteum (CL). As the CL continues secreting progesterone, PYO would develop following endometritis. Due to prohibited use of artificial luteolytic hormones in US certified organic dairies, conventional therapies consisting of administration of prostaglandin F2α, are not applicable. The objective of this study was to evaluate the efficacy of two acupuncture procedures on the treatment of persistent CL in cows with PYO. We hypothesized that acupuncture would reduce CL diameter and serum progesterone (P4) concentrations, leading to regression of PYO. Holstein cows with PYO, at an USDA certified organic dairy farm in Northern Colorado, were enrolled in a randomized controlled clinical trial and assigned to 1 of 3 treatments: (1) control pyometra (CP; no treatment; n = 17); (2) electroacupuncture (EAP; n = 15); and (3) laser acupuncture (LAP; n = 15). Each cow received three 9-min (EAP) or 20-min (LAP) acupuncture sessions in alternate days. All study cows had blood samples collected for determination of serum progesterone concentration at d0, and at d2, d4, d11, d18, and d25 after first treatment. The ovaries were scanned by transrectal ultrasonography at -3d, d0, d2, d4, d11, and d18 to determine the diameter of the CL. The effect of treatment in the outcome variables was evaluated by ANOVA and by repeated measures analyses, accounting for baseline data (CL diameter and progesterone serum concentration). Average ± SE change in CL diameter from d0 to d18 were 0.94 ± 1.0 mm, 0 ± 1.0 mm, and - 0.33 ± 1.0 mm for CP, EAP, and LAP, respectively. The repeated measures analysis indicated no significant differences for CL diameter among groups. None of the study cows had serum progesterone values <1 ng/ml by the end of the monitoring period (d25) and average ± SE change from d0 to d25 were - 4.0 ± 1.97 ng/ml, -0.76 ± 2.1 ng/ml, and 3.24 ± 1.9 ng/ml for CP, EAP, and LAP, respectively. The repeated measures analysis indicated no significant differences for serum progesterone concentrations among groups. On farm cow records reviewed 150 d after treatment indicated that 2 cows in EAP and 1 cow in LAP conceived 38 d, 68 d, and 38 d, after treatment completion. In conclusion, acupuncture was not an effective treatment for persistent CL in cows with PYO, during the monitoring period.

International Nosocomial Infection Control Consortium (INICC) report, data summary of 45 countries for 2012-2017: Device-associated module

BACKGROUND

We report the results of International Nosocomial Infection Control Consortium (INICC) surveillance study from January 2012 to December 2017 in 523 intensive care units (ICUs) in 45 countries from Latin America, Europe, Eastern Mediterranean, Southeast Asia, and Western Pacific.

METHODS

During the 6-year study period, prospective data from 532,483 ICU patients hospitalized in 242 hospitals, for an aggregate of 2,197,304 patient days, were collected through the INICC Surveillance Online System (ISOS). The Centers for Disease Control and Prevention-National Healthcare Safety Network (CDC-NHSN) definitions for device-associated health care-associated infection (DA-HAI) were applied.

RESULTS

Although device use in INICC ICUs was similar to that reported from CDC-NHSN ICUs, DA-HAI rates were higher in the INICC ICUs: in the medical-surgical ICUs, the pooled central line-associated bloodstream infection rate was higher (5.05 vs 0.8 per 1,000 central line-days); the ventilator-associated pneumonia rate was also higher (14.1 vs 0.9 per 1,000 ventilator-days,), as well as the rate of catheter-associated urinary tract infection (5.1 vs 1.7 per 1,000 catheter-days). From blood cultures samples, frequencies of resistance, such as of Pseudomonas aeruginosa to piperacillin-tazobactam (33.0% vs 18.3%), were also higher.

CONCLUSIONS

Despite a significant trend toward the reduction in INICC ICUs, DA-HAI rates are still much higher compared with CDC-NHSN's ICUs representing the developed world. It is INICC's main goal to provide basic and cost-effective resources, through the INICC Surveillance Online System to tackle the burden of DA-HAIs effectively.

Efficacy of non-antibiotic treatment options for digital dermatitis on an organic dairy farm

The objective of this study was to evaluate the efficacy of two non-antibiotic treatment options for digital dermatitis (DD) on an organic certified dairy farm. A randomized clinical trial was conducted using 70 multiparous Holstein cows with an early DD lesion at a USDA certified organic dairy farm in Northern Colorado, USA. Cows were enrolled in the study based on the presence of early DD lesions (scores M1 and M2) and randomly assigned to one of three treatments: (1) topical application of copper sulfate and iodine (CUI); (2) topical application of honey and iodine (HOI); and (3) control subject to no treatment (CON). Cows were evaluated at enrolment and on days 3, 12, 28, and 120 post treatment for pain and lesion size and received a locomotion and a lesion score. Cure was defined as the transition from active to non-active stages (M1/M2 to M0 or M4). The formulations had variable effects on the treatment of DD. The cure rate was numerically higher for CUI on all follow up days. The proportion of cows experiencing pain on d3 after treatment was greater in CON, followed by HOI and CUI. However, this proportion increased in HOI during the follow up period. The CUI group had a greater reduction in lesion size and larger lesions persisted in HOI. Non-antibiotic treatment formulations were partially effective in the treatment of DD in organic dairy cows: The two non-antibiotic formulations resulted in an earlier transition to mature lesions compared with the control group. The CUI combination was the most effective treatment in reducing lesion size, pain, and lameness in affected cows. However, this combination had short-term efficacy, which did not persist throughout the duration of the study. The HOI combination produced only transient reduction in lesion size.

Modelling Observation Correlations for Active Exploration and Robust Object Detection

Today, mobile robots are expected to carry out increasingly complex tasks in multifarious, real-world environments. Often, the tasks require a certain semantic understanding of the workspace. Consider, for example, spoken instructions from a human collaborator referring to objects of interest; the robot must be able to accurately detect these objects to correctly understand the instructions. However, existing object detection, while competent, is not perfect. In particular, the performance of detection algorithms is commonly sensitive to the position of the sensor relative to the objects in the scene. This paper presents an online planning algorithm which learns an explicit model of the spatial dependence of object detection and generates plans which maximize the expected performance of the detection, and by extension the overall plan performance. Crucially, the learned sensor model incorporates spatial correlations between measurements, capturing the fact that successive measurements taken at the same or nearby locations are not independent. We show how this sensor model can be incorporated into an efficient forward search algorithm in the information space of detected objects, allowing the robot to generate motion plans efficiently. We investigate the performance of our approach by addressing the tasks of door and text detection in indoor environments and demonstrate significant improvement in detection performance during task execution over alternative methods in simulated and real robot experiments.

[Low back pain with 'red flags': a case of spondylodiscitis]

Spondylodiscitis is a serious clinical entity. Despite the decrease in mortality from about 25% in the pre-antibiotic era to near 5%, it remains significant and the associated morbidity is still relevant. The rate of residual neurological deficits among survivors is around 7%. In 30% of patients some related symptoms persist, the most important being pain. The authors report the case of a 74-year-old male patient with recent onset low back pain, which caused considerable disability. With this work the authors intend to alert to the fact that in a patient with a common symptom such as low back pain, the presence of "red flags" requires a quick investigation and diagnosis in order to prevent serious damage.

Mutational pattern of the nurse shark antigen receptor gene (NAR) is similar to that of mammalian Ig genes and to spontaneous mutations in evolution: the translesion synthesis model of somatic hypermutation

The pattern of somatic mutations of shark and frog Ig is distinct from somatic hypermutation of Ig in mammals in that there is a bias to mutate GC base pairs and a low frequency of mutations. Previous analysis of the new antigen receptor gene in nurse sharks (NAR), however, revealed no bias to mutate GC base pairs and the frequency of mutation was comparable to that of mammalian IgG. Here, we analyzed 1023 mutations in NAR and found no targeting of the mechanism to any particular nucleotide but did obtain strong evidence for a transition bias and for strand polarity. As seen for all species studied to date, the serine codon AGC/T in NAR was a mutational hotspot. The NAR mutational pattern is most similar to that of mammalian IgG and furthermore both are strikingly akin to mutations acquired during the neutral evolution of nuclear pseudogenes, suggesting that a similar mechanism is at work for both processes. In yeast, most spontaneous mutations are introduced by the translesion synthesis DNA polymerase zeta (REV3) and in various DNA repair-deficient backgrounds transitions were more often REV3-dependent than were transversions. Therefore, we propose a model of somatic hypermutation where DNA polymerase zeta is recruited to the Ig locus. An excess of DNA glycosylases in germinal center reactions may further enhance the mutation frequency by a REV3-dependent mutagenic process known as imbalanced base excision repair.

Effects of dietary gossypol on aspects of semen quality, sperm morphology and sperm production in young Brahman bulls

Eight young reproductively normal Brahman bulls (average age and bodyweight 20 months and 500 kg, respectively) received either cottonseed meal delivering 8.2 g free gossypol/bull/d (treatment group, n=4) or soybean meal (control group, n=4) for 12 wk. After adjustment (1 wk), weekly procedures (11 wk) included blood collection, scrotal circumference measurement and electroejaculation. Semen assessments included sperm motility, percentage of live spermatozoa, general sperm morphology (using brightfield microscopy), and midpiece morphology (using DIC microscopy). After sacrifice (Week 12), sperm production rates (daily and per gram testicular parenchyma) were determined. Treated bulls did not differ from controls in scrotal circumference or the percentage of live spermatozoa. Sperm motility differed at Weeks 9 (P<0.05), 10 and 11 (both P=0.06). Treated bulls had fewer normal spermatozoa at Weeks 5 (P<0.05), 6 (P<0.01) and 7 thru 11 (P<0.001). Beginning from Week 3, treated bulls showed an increased proportion of sperm midpiece abnormalities (P<0.05) which stabilized at 52 to 62.5% between Weeks 5 and 11 (P<0.01 or P<0.001). Treated bulls also had lower sperm production than untreated bulls, both on a daily (P<0.01) and per gram testicular parenchyma (P<0.001) basis. A cottonseed supplement providing 8.2 g of free gossypol per bull per day had adverse effects upon both sperm morphology and spermatogenesis in young Brahman bulls, with the former being first evident within 3 to 4 weeks of feeding of cottonseed meal.

The effect of gossypol in cottonseed meal on performance and on hematological and semen traits in postpubertal Brahman bulls

The effects of a cottonseed meal diet containing high levels of free gossypol on hematological traits, including erythrocyte osmotic fragility and semen characteristics, were examined during an 11-week period. Eight Brahman bulls were randomly assigned to 1 of 2 groups. The control group (n=4) was fed a mixture of soybean meal and corn. The treated group (n=4) was fed a mixture of cottonseed meal and corn. Both groups were allowed hay free choice. The treated group consumed 8.2 g of free gossypol per bull per day. The percentage of normal spermatozoa was lower (P<0.01) in the treated than in the control group from Week 5 (49+/-9.8 vs 83+/-3.2%), which was primarily influenced by changes in mid piece morphology in the treated bulls. Erythrocyte osmotic fragility was higher (P<0.001) in the treated than in the control group over the entire study period, although group values diverged more acutely from Week 7 of treatment. Sperm motility was lower (P=0.04) in treated bulls than in control bulls at Week 9 (52+/-9.8 vs 82+/-6.2%). These data suggest that concurrent discernable changes in bull erythrocyte osmotic fragility and in semen characteristics can occur following commencement of a diet containing 8.2g of free gossypol per day.

Histoplasmosis in the acquired immunodeficiency syndrome (AIDS): treatment with itraconazole and fluconazole

The manifestations of histoplasmosis in 20 patients with the acquired immunodeficiency syndrome are presented. In this series, patients were treated with either itraconazole or fluconazole. Twelve patients received treatment with itraconazole at 400 mg/day, including two patients who had not responded to treatment with fluconazole at 100 mg/day. Of the responses, seven were classified as remissions (mean treatment duration of 24 months), two as improvements, and three as failures. Ten patients received fluconazole. Of the responses, three were classified as remissions (mean treatment duration of 12 months), one as improvement, and six as failures. Of the 10 patients treated with fluconazole, five received doses of 100 mg/day, and five were given doses of 400 or 800 mg/day. The differences in outcome among the five patients receiving the lower dose of fluconazole (one remission, one improvement, and three failures) and the five patients given the higher doses of fluconazole (two remissions and three failures) were negligible. One other patient showed signs of histoplasmosis while receiving fluconazole at 50 mg/day for treatment of thrush. Three failures (two treated with itraconazole and one with fluconazole) followed lapses in azole therapy because of associated conditions. Azole therapy was well tolerated. The treatment responses in this pilot series appear promising in comparison with those reported in the literature with amphotericin B or ketoconazole.

Directional asymmetries of optokinetic nystagmus: developmental changes and relation to the accessory optic system and to the vestibular system

To investigate the relation of the directional organization of the accessory optic system (AOS) to that of its principal behavioral output, optokinetic nystagmus (OKN), we measured the eye velocity during OKN in response to 14 directions of stimulus motion, including horizontal, vertical, cyclorotational (rotations about the optic axis), and intermediate directions in both neonatal and older chickens. We found substantial and consistent OKN asymmetries between opposite directions of stimulus motion when the stimuli were viewed monocularly; the asymmetries were largest to combinations of cyclorotational and vertical stimulus motion and to horizontal stimulus motion. The highest gain of OKN in the older animals was in response to two directions of stimulus motion: horizontal temporal-to-nasal and a combination of excyclorotation and downward. In addition, OKN to upward moving stimuli was consistently better than to downward stimuli. The association of high OKN gain in the older animals with the pattern of visual motion produced by head movements exciting the contralateral anterior semicircular canal suggests a possible vestibular organization of the optokinetic system. The response pattern of the newly hatched chickens differed in three ways from that of the older animals: in the non-horizontal stimulus directions the best direction was to upward and excyclorotational stimulus motion; the horizontal asymmetry was somewhat less strong; and the OKN gain to high velocity horizontal stimulus motion was lower. The change in directional pattern of OKN over the first weeks of life appears related to a corresponding change in anatomy of the AOS.

Avian vestibuloocular reflex: adaptive plasticity and developmental changes

1. This study demonstrates plasticity of the vestibuloocular reflex (VOR) in chickens and compares it to that of other species and to that of newly hatched chicks. Adaptive changes in the VOR were induced by subjecting the animals to combinations of visual and vestibular stimuli that simulated the effect of the VOR being either too low in gain or reversed in phase. 2. The VOR of chickens resembles that of mammals, but the curve of phase lead versus frequency seems shifted toward higher frequencies. The VOR of newly hatched chicks has extremely low gain (less than 0.1). 3. In both the older and newly hatched animals, the VOR gain increased substantially after 2 h in an environment in which the imposed en bloc rotations produced increased retinal image slip in the normal directions. Similarly, 2 h of reversed retinal image slip produced decreased VOR gain and, in some cases, reversal fo the phase of the VOR. The gain changes were largest at the "training" frequency. The phase changes were in the direction of increased phase lead. Changes in the gains of the optokinetic responses and of the combination of VOR and optokinetic responses were also seen, especially in the newly hatched animals. 4. The newly hatched birds showed the largest VOR changes in the increased-gain situation, whereas the older birds showed the largest changes in the reversed-phase situation, as assessed by the changes in the average retinal slip velocity experienced. These results may well not be a consequence of differences in age, per se, but of differences in average retinal slip experienced in the two experimental situations at the start of the trial because of the lower VOR gain of the newly hatched animals. There seems to be no dramatic difference in VOR plasticity between newly hatched and older birds. 5. Our results with reversed visual motion are substantially different from those obtained in similar studies on rabbits, suggesting that these two species use different error signals to control the adaptive adjustment of the VOR.