Chlamydial infection and on-farm risk factors in dairy cattle herds in South East Queensland.

Chlamydial infections in dairy cattle are common and have been sporadically associated with reduced performance and severe disease manifestations. While chlamydial infections are well described in sheep, very little is known about the epidemiology of these infections in dairy cattle in Australia. In this study, we screened for chlamydial infections and assessed on-farm risks in dairy cattle herds from Southeast Queensland (SE Qld) region of Australia. In total, 228 paired vaginal and rectal swabs were collected from 114 visually healthy dairy cows from four farms in SE Qld. Risk factors were rated by observational study and included: hygiene and cleanliness of cows, walkway and parlour, incidence of perinatal mortality, external replacements, mode of breeding, calving pen management, heat reduction strategies, and feed ration usage. Testing for chlamydial pathogens (Chlamydia pecorum, Chlamydia psittaci and Chlamydia abortus) was done using species-specific quantitative polymerase chain reaction (qPCR) assays. Detected rates of chlamydial infection were evaluated against the on-farm risk factors. C. pecorum infection was widespread in all four farms, with 56.1% (64/114) of individual animals shedding this organism from vaginal and rectal, or both sites. C. abortus and C. psittaci were not detected in any animals. No association was found to exist with risk factors and C. pecorum infection rates in our study, however the number of Chlamydia positive animals was statistically different between the herds. This study suggests that subclinical chlamydial infections may impact on dairy herd health at the production level rather than affecting individual animal.

Antibody response against koala retrovirus (KoRV) in koalas harboring KoRV-A in the presence or absence of KoRV-B.

Koala retrovirus (KoRV) is in the process of endogenization into the koala (Phascolarctos cinereus) genome and is currently spreading through the Australian koala population. Understanding how the koala's immune system responds to KoRV infection is critical for developing an efficacious vaccine to protect koalas. To this end, we analyzed the antibody response of 235 wild koalas, sampled longitudinally over a four-year period, that harbored KoRV-A, and with or without KoRV-B. We found that the majority of the sampled koalas were able to make anti-KoRV antibodies, and that there was a linear increase in anti-KoRV IgG levels in koalas up to approximately seven years of age and then a gradual decrease thereafter. Koalas infected with both KoRV-A and KoRV-B were found to have slightly higher anti-KoRV IgG titers than koalas with KoRV-A alone and there was an inverse relationship between anti-KoRV IgG levels and circulating KoRV viral load. Finally, we identified distinct epitopes on the KoRV envelope protein that were recognized by antibodies. Together, these findings provide insight into the koala's immune response to KoRV and may be useful in the development of a therapeutic KoRV vaccine.

The ties that bind: perceived social support, stress, and IBS in severely affected patients.

BACKGROUND: This study assessed the association between social support and the severity of irritable bowel syndrome (IBS) symptoms in a sample of severely affected IBS patients recruited to an NIH-funded clinical trial. In addition, we examined if the effects of social support on IBS pain are mediated through the effects on stress. METHODS: Subjects were 105 Rome II diagnosed IBS patients (F = 85%) who completed seven questionnaires which were collected as part of a pretreatment baseline assessment. KEY RESULTS: Partial correlations were conducted to clarify the relationships between social support and clinically relevant variables with baseline levels of psychopathology, holding constant number of comorbid medical diseases, age, gender, marital status, ethnicity, and education. Analyses indicated that social support was inversely related to IBS symptom severity. Social support was positively related with less severe pain. A similar pattern of data was found for perceived stress but not quality of life impairment. Regression analyses examined if the effects of social support on pain are mediated by stress. The effects of social support on bodily pain were mediated by stress such that the greater the social support the less stress and the less pain. This effect did not hold for symptom severity, quality of life, or psychological distress. CONCLUSIONS & INFERENCES: This study links the perceived adequacy of social support to the global severity of symptoms of IBS and its cardinal symptom (pain). It also suggests that the mechanism by which social support alleviates pain is through a reduction in stress levels.

Quadriceps concentric and eccentric exercise 2: differences in muscle strength, fatigue and EMG activity in eccentrically-exercised sore and non-sore muscles.

The purpose of this study was to determine whether the previously reported muscle weakness and increases in EMG and EMG/force ratio after eccentric exercise were related to ensuing soreness or simply to the exercise mode. Delayed-onset muscle soreness, maximal voluntary force and the surface electromyogram (EMG) of the quadriceps were studied in 10 healthy male subjects following 20 min of bench-stepping with a constant leading leg. Prior to stepping and at 0, 0.25, 0.50, 0.75, 1, 3, 24 and 48 h afterwards the subjects performed a 30 s isometric maximal voluntary contraction (MVC) of the extensors of each leg during which the isometric force and the root mean square voltage of the surface EMG (rms EMG) were recorded. Muscle soreness was recorded prior to and at 0, 0.75, 3, 24 and 48 h after the stepping task by means of a force probe. No soreness was experienced in the concentrically exercised muscles, but in the eccentrically exercised muscles 5 subjects were not sore and 5 experienced soreness after 24 h, increasing to 48 h. There were no significant differences between sore and non-sore muscles in muscle weakness, fatigue during 30 s, the EMG amplitudes or the EMG/force ratios during peak force and the 30 s MVC (p >0.05). Muscle weakness following eccentric exercise was related to the exercise mode and was independent of subsequent soreness. Both weakness and soreness may be related to muscle damage, but involve different mechanisms.

Quadriceps concentric and eccentric exercise 1: changes in contractile and electrical activity following eccentric and concentric exercise.

The purpose of this study was to determine whether or not losses of strength or endurance following eccentric and concentric exercise are associated with reduced excitation. The effects of eccentric and concentric work on maximal voluntary isometric contraction (MVC) and surface electromyogram (EMG) of the quadriceps were studied in 10 healthy male subjects following bench-stepping for 20 min with a constant leading leg. Prior to stepping and at 0, 0.25, 0.50, 0.75, 1, 3, 24 and 48 h afterwards the subjects performed a 30 s leg extension MVC with each leg during which the isometric force and the root mean square voltage of the EMG were recorded. In the eccentrically exercised muscles (ECC), MVC0-3 (force during the first 3 s of contraction) fell immediately after the bench-stepping exercise to 88+/-2% (mean+/-SE) of the pre-exercise value and remained significantly lower than the concentrically exercised muscles (p<0.05). The muscle weakness in the ECC could not be attributed to central fatigue as surface EMG amplitude at MVC0-3 increased during the recovery period. Muscle weakness after eccentric exercise appears to be due to contractile failure, which is not associated with a reduction in excitation as assessed by surface EMG. Muscular fatigue over 30 s did not change in the two muscle groups after exercise (p = 0.79), indicating that the ECC were weaker but not more fatiguable after exercise.

Dimensions and categories: the "big five" factors and the DSM personality disorders.

The five-factor model of personality, which has been widely studied in personality psychology, has been hypothesized to have specific relevance for DSM-defined personality disorders. To evaluate hypothesized relationships of the five-factor model of personality to personality disorders, 144 patients with personality disorders (diagnosed via a structured interview) completed an inventory to assess the five-factor model. Results indicated that the majority of the personality disorders can be differentiated in theoretically predictable ways using the five-factor model of personality. However, while the personality disorders as a whole appear to be differentiable from normal personality functioning on the five factors, the patterns are quite similar across the disorders, a finding that may provide some insight into the general nature of personality pathology but may also suggest problems with discriminant validity. Third, it does not appear that considering disorders as special combinations of features (as might be expected in some categorical models) is more informative than considering them as the sum of certain features (as might be expected in a dimensional model).

Alcohol and the continuation of early marital aggression.

BACKGROUND: Husband alcohol use has frequently been found to be related to husband-to-wife marital violence. Research has demonstrated a prospective link between husband alcohol use before marriage and husband-to-wife aggression in the first year of marriage. The present study examined the relationships of husband violence, marital conflict, and couple's alcohol use in the first year of marriage to husband-to-wife marital violence in the second and third years of marriage. METHODS: Newlywed couples were recruited at the time of marriage and were interviewed regarding alcohol use and experience with violence before marriage, 1 year after marriage, and 3 years after marriage. RESULTS: Year 1 violence was predictive of subsequent marital violence. Husband and wife drinking patterns in the first year of marriage interacted to predict violence in later years. The most violence in subsequent years occurred in couples where the husband was a heavy drinker and the wife was not. Husbands who were violent in year 1 were more likely to be violent in later years. When no violence occurred in the first year, frequent use of verbal aggression in year 1 was predictive of violence in subsequent years. CONCLUSIONS: The predictive value of husband drinking patterns for subsequent violence extends beyond the transition to marriage. The fact that husband and wife alcohol use interacted to predict future aggression suggests that the relationship between husband alcohol use and marital violence is not spurious nor the result of conflict and violence promoting alcohol use. The findings may reflect multiple instances of acute intoxication and/or alcohol-related stress and conflict within the relationship, both of which may increase the likelihood of aggression.

Drinking and marital aggression in newlyweds: an event-based analysis of drinking and the occurrence of husband marital aggression.

OBJECTIVE: Research suggests that domestically violent men are more likely to be heavy drinkers than nonviolent men. However, very little data has addressed the relationship between the occurrence of a domestic violence episode and the co-occurrence of husband or wife alcohol consumption. The purpose of this study was to examine the relationship between husband and wife drinking and whether the most serious conflict involved verbal aggression, moderate physical aggression or severe physical aggression. METHOD: Newlywed couples (n = 366) who were assessed with respect to risk factors for marital violence at the time of marriage were interviewed at the end of their first year of marriage. These in-person interviews focused on characteristics (location, presence of other people, husband drinking, wife drinking) of the most severe verbal conflict, and the first and the most severe episode of physical aggression. RESULTS: After controlling for individual difference risk factors including husband and wife drinking patterns, husband drinking was more likely in episodes of physical vs episodes of verbal aggression. This finding was consistent in both husband and wife, and consistent in both between-groups and within-groups analyses. Wife drinking was largely unrelated to occurrence or severity of violence. CONCLUSIONS: These results support the contention that alcohol use may contribute to the occurrence and/or severity of domestic violence, particularly in the early stages of marriage.

The modeling of alcohol consumption: a meta-analytic review.

OBJECTIVE: Modeling, or the imitation of another's behavior, has been proposed to influence alcohol consumption. The literature dealing with effects of modeling on alcohol consumption was reviewed using meta-analytic procedures in order to determine the strength of the modeling effect and the variables that moderate the effect. METHOD: Thirteen studies were examined in which participant's alcohol consumption in the presence of a high consumption model was compared to a low consumption model condition or a no-model condition. Analyses were conducted for the four dependent measures utilized in the literature: amount consumed, blood alcohol concentration, number of sips taken and volume per sip. Mean effect sizes (d) were calculated for each dependent measure and moderator variables were examined. RESULTS: Modeling had a significant effect on all four dependent measures, with the strongest effects being on amount consumed and blood alcohol concentration. In addition, analyses identified numerous variables that moderate the effect of modeling on alcohol consumption, including the drinking history of the participant, the drinking task used and the nature of the interaction between model and participant. CONCLUSIONS: Results indicated that modeling has a strong effect on alcohol consumption; however, several variables do mediate this effect.

The relationship between fatigue, psychological and immunological variables in acute infectious illness.

OBJECTIVE: The aim of this paper is to explore the longitudinal relationships between physical and psychological symptoms and immunological factors following acute infective illnesses. METHOD: Preliminary data from a prospective investigation of patients with serologically proven acute infectious illnesses due to Epstein-Barr virus (EBV), Ross River virus (RRV) or Q fever are reported. Patients were assessed within 4 weeks of onset of symptoms and then reviewed 2 and 4 weeks later. Physical illness data were collected at interview. Psychological and somatic symptom profiles were assessed by standardised self-report questionnaires. Cell-mediated immune (CMI) function was assessed by measurement of delayed-type hypersensitivity (DTH) skin responses. RESULTS: Thirty patients who had been assessed and followed over the 4-week period (including 17 patients with EBV, five with RRV and eight with Q fever) were included in this analysis. During the acute phase, profound fatigue and malaise were the most common symptoms. Classical depressive and anxiety symptoms were not prominent. Initially, 46% of cases had no DTH skin response (i.e. cutaneous anergy) indicative of impaired cellular immunity. Over the 4-week period, there was a marked improvement in both somatic and psychological symptoms, although fatigue remained a prominent feature in 63% of subjects. The reduction in reported fatigue was correlated with improvement in the DTH skin response (p = 0.001) and with improvement in General Health Questionnaire (GHQ) scores (p < 0.01). CONCLUSIONS: Acute infectious illnesses are accompanied by a range of nonspecific somatic and psychological symptoms, particularly fatigue and malaise rather than anxiety and depression. Although improvement in several symptoms occurs rapidly, fatigue commonly remains a prominent complaint at 4 weeks. Resolution of fatigue is associated with improvement in cell-mediated immunity.

Feigned mental disorder in prisoners referred to forensic mental health services.

This paper describes a study that aimed to identify the extent to which feigning of mental illness represents a significant problem in prisoners referred to a medium secure unit. A clinical method was used to assess the prisoners, employing the Structured Interview of Reported Symptoms (SIRS) and selected Minnesota Multiphasic Personality Inventory-2 (MMPI-2) validity indices. Stringent criteria were used to classify 60 consecutive referrals to a secure unit as feigning mental disorder or not. In addition, the study examined characteristic differences, on a number of selected variables, between those prisoners who feign and those who respond honestly. The personality profiles of prisoners who feign were also investigated. Analysis of data showed that 32% of the sample (P < 0.01) could be classified as fabricating or exaggerating symptoms of mental illness. It is suggested that such presentations may be more prevalent than previously considered. Few differences were observed between the groups on selected variables, although prisoners who feigned mental illness demonstrated significantly higher dependent and anxious (avoidant) personality types. The implications of the findings are discussed in relation to available models of feigned presentations.

Differences in muscle contractile characteristics among bodybuilders, endurance trainers and control subjects.

The purpose of this investigation was to compare the myosin heavy chain (MHC) isoform expression of the triceps brachii muscle and isoinertial, isometric and isokinetic strength indices in competitive bodybuilders (CB, n = 5), recreational resistance trainers (RT, n = 5), endurance-trained rowers (ER, n = 5) and control (C, n = 5) subjects. Muscle tissue samples were analysed for MHC isoform content using 6% sodium dodecyl sulphate-polyacrylamide gel electrophoresis. The CB possessed significantly smaller (P < 0.05) percentage of MHC type IIb proteins [12.92 (SD 7.08)%] than RT [30.08 (SD 6.58)%] ER [31.20 (SD 2.74)%] and C [38.22 (SD 2.95)%] groups (i.e. CB < RT approximately ER < C). While the content of MHC type IIa isoforms did not differ significantly between the two resistance-trained groups [CB = 55.76 (SD 5.38)%; RT = 45.72 (SD 7.8)%], CB presented significantly more type IIa MHC isoforms than ER [42.84 (SD 2.98)%] and C [34.72 (SD 1.57)%] subjects (i.e. CB approximately RT > ER approximately C). The MHC type I protein content did not differ significantly among RT [24.20 (SD 4.89)%] ER [25.38 (SD 1.67)%] and C [27.06 (SD 1.81)%] groups. The CB [31.32 (SD 2.67)%] presented significantly more type I MHC isoforms only in comparison with RT. However, when changes in the percentage of MHC type I isoforms were converted to effect sizes (ES), it appeared that low statistical power rather than the absence of an effect accounted for the nonsignificant differences between CB and other groups (i.e. CB > RT approximately ER approximately C). Significant differences existed in isoinertial strength among the trained athletes (i.e. CB > RT > ER approximately C), while isometric and isokinetic strength were not significantly different among any of the trained groups. However, the ES transformation of data demonstrated that large differences existed between resistance-trained groups and ER for isometric and isokinetic strength (i.e. CB approximately RT > ER approximately C). A statistically significant negative correlation (P < 0.001) was found between MHC type IIb isoforms and isoinertial strength index (r = -0.68). The MHC type IIa proteins were positively related to all the strength measures considered (r = 0.51 0.61; P < 0.001). These data demonstrated different patterns of MHC isoform expression among the different groups of athletes and it is suggested that these differences on occasion may affect the expression of strength.

Effect of cryotherapy on muscle soreness and strength following eccentric exercise.

The purpose of this study was to determine whether a post-exercise cryotherapy protocol could facilitate recovery of elbow flexor strength and reduce the severity of delayed onset muscle soreness following eccentric exercise. Eight resistance-trained males (23 +/- 3 yr) performed 64 eccentric elbow flexions with each arm. One arm was subjected to five, 20 minute immersions in a 5 +/- 1 degree C ice-water bath interspersed by 60 minute rest periods. The non-immersed arm served as the control. A main effect for time was observed for all dependent variables (p < 0.05). Isometric torque (mean SE) decreased from a pre-exercise value of 87.9 +/- 4.5 Nm to 65.2 +/- 4.5 Nm immediately post-exercise. Isokinetic torque at 60 and 300 degrees x s(-1) decreased from 71.0 +/- 3.5 NM and 48.4 +/- 2.8 Nm to 55.8 +/- 3.3 Nm and 39.8 +/- 3.1 Nm, respectively. All torque measures returned to pre-test levels by 72 h. Muscle soreness peaked 48 h post-exercise and was evident until 120 h. Limb volume increased by 200 +/- 18 ml immediately post-exercise (p < 0.05) but was not significantly elevated thereafter. No significant difference between the immersed and control arms were observed for any variable. The result suggest that the use of cryotherapy immediately following damaging eccentric exercise may not provide the same therapeutic benefits commonly attributed to cryotherapy following traumatic muscle injury.

Desistance of husband aggression in the early years of marriage.

Desistance of husband marital aggression was investigated over a 3-year time span. One hundred and eighty-eight couples who had experienced husband aggression in the first year of marriage were followed to the third year of marriage. Overall 23.9% of these husbands had no violence in years 2 and 3. However, desistance rates differed as a function of the type of violence that occurred in year 1. Husbands who had only one incident of minor physical aggression and no severe violence in year 1 were most likely to desist in years 2 and 3 while those who used severe violence in year 1 were least likely to desist. Subsequent analyses showed that wife's depression and dissatisfaction with the partner increased from years 1 to 3 when desistance did not occur.

Psychological intervention for older hip fracture patients.

1. Although there are sophisticated surgical procedures for hip fracture repair, a substantial proportion of patients never return to pre-fracture levels of physical function. Factors that influence the recovery of older hip fracture patients represent important areas to study in order to more precisely predict outcome. 2. Research findings suggest that elevated depressive symptoms and cognitive impairment may negatively affect recovery, while mental alertness, emotional stability, and social involvement positively affect recovery. Thus, hip fracture and its subsequent disability must be studied as a biopsychosocial phenomenon, rather than merely as a physiological event. 3. Older hip fracture patients may be at higher risk for psychological problems related to the traumatic nature of the injury. A comprehensive psychological assessment at admission can assist the nursing staff to determine which patients are at higher risk for emotional distress.

Substance P and substance P receptor histochemistry in human neurodegenerative diseases.

Substance P immunoreactivity is localized in discrete subsets of neurons in the human cerebral cortex and basal ganglia. In the normal human cerebral cortex, a subset of aspiny local circuit neurons in deep cortical layers and the cortical subplate contain preprotachykinin mRNA and substance P immunoreactive. These neurons, which contain NADPH diaphorase (NO synthase) activity, are strikingly depleted in Alzheimer's disease--in contrast to other local circuit neurons--suggesting that they may be an early target of the degenerative process. In the human basal ganglia, substance P immunoreactivity and mRNA are localized in a subset of spiny striatal neurons that project to the internal segment of the globus pallidus. These neurons are enriched in D1 dopamine receptors and dynorphin, and are calbindin and DARP 32 immunoreactive. A separate subset of aspiny striatal local circuit neurons also contain substance P immunoreactivity. Fiber and terminal staining is prominent in the matrix compartment of the ventromedial striatum and persists dorsally as a rim outlining patches that contain lesser amounts of immunoreactivity. Intense fiber and terminal staining is found in the pars reticulata of the substantia nigra. In Huntington's disease, substance P is depleted in the striatum in parallel with the dorsoventral gradient of neuronal loss. Terminal staining is progressively depleted in the pallidum and substantia nigra in tandem with striatal atrophy. Substance P receptor immunoreactivity, defined with two polyclonal antisera raised against synthetic peptides derived from the substance P receptor sequence, intensely labels a subset of large neurons in the nucleus basalis and striatum identical to neurons labeled with choline acetyltransferase and nerve growth factor receptor antibodies (although striatal cholinergic neurons do not contain nerve growth factor receptor immunoreactivity in the human). These cholinergic neurons resist degeneration in Huntington's disease but are sensitive to degeneration in Alzheimer's disease. Less intensely labeled neurons include pyramidal neurons in the hippocampal CA2 field, nonpyramidal neurons in CA1-4, pyramidal and nonpyramidal neurons in deep neocortical layers and in the cortical subplate. Substance P receptor immunoreactivity is not well defined in the human globus pallidus or substantia nigra.

The influence of high-intensity exercise training on the Wlim-Tlim relationship.

When exercise to exhaustion is performed using at least two different intensities, work to fatigue (Wlim) can be expressed as a linear function of time to fatigue (Tlim). Whereas the slope of this function is related to endurance ability, the y-intercept is associated with the potential to perform high intensity interval exercise. The purpose of the present investigation was to determine the influence of 8-wk intermittent high-intensity exercise training on the y-intercept derived from the Wlim-Tlim relationship. Eight healthy, untrained male students (19.1 +/- 0.6 yr) completed five 60-s bouts of maximal exercise on the cycle ergometer, three times a week, for 8 wk. Seven controls avoided regular activity for the same period. Prior to and immediately following the training period, the Wlim-Tlim relationship, VO2max, and total work completed in five 60-s exercise bouts on the cycle ergometer were determined. Correlational analysis established relationships between the y-intercept and total work accomplished in the interval test pre- (r = 0.90; P < 0.01; N = 15) and post-training (r = 0.92; P < 0.01; N = 15), confirming that the y-intercept is related to the ability to perform exercise of this nature. Moreover, the "anaerobic" energy yield, calculated from total work and oxygen consumed during the interval exercise, was also related to the y-intercept (r = 0.78; P < 0.01). Interval training significantly increased both the y-intercept (P = 0.0015) and total work accomplished in the interval test (P = 0.001), while the slope of the Wlim-Tlim relationship (critical power) remained unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

Endurance training enhances critical power.

The present investigation was conducted to determine whether critical power (CP) assesses the ability to perform continuous aerobic exercise and to determine whether training-induced changes in aerobic endurance are reflected by changes in the slope, but not the y-intercept of the CP function. Twelve healthy, active, but untrained male students (mean age +/- SD = 19.1 +/- 0.8 yr) undertook 8 wk of cycle ergometer endurance training (30-40 min a day, three times a week) at an intensity corresponding to their CP. Six control subjects of similar age and initial training status refrained from regular exercise for the same period. Before and immediately following the training period, each of the 18 participants completed three cycle ergometer tests to determine their CP function, an incremental exercise task to establish their maximal oxygen uptake (VO2max), and 40 min of continuous cycle ergometry at or near their calculated CP. CP was significantly correlated with endurance time at 270 W (r = 0.65, P < 0.05) and with the mean power that could be maintained for 40 min (r = 0.87-0.95, P < 0.01), but overestimated the latter by less than 6%. In response to endurance training, CP increased from a mean of 196 +/- 40.9 W to 255 +/- 28.4 W (31%) (ANCOVA, P < 0.01), while the mean power output maintained for 40 min of exercise increased from 190 +/- 34.5 W to 242 +/- 34.9 W (28%). VO2max increased from 49.2 +/- 7.8 ml.kg-1.min-1 to 53.4 +/- 6.4 ml.kg-1.min-1 (8.5%) (P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Histopathologic observations in weanling B6C3F1 mice and F344/N rats and their adult parental strains.

Weanling Fischer 344/N (F344) rats and the first filial hybrid of C57BL/6 x C3H (B6C3F1) mice and retired breeders from the parental stocks of these strains were monitored over a 5-yr-period by examining the histopathology of selected organs and comparing those results to viral and mycoplasmal serology and the intestinal tract bacterial flora of each animal on an individual basis. Serology gave no evidence of viral infection, but Mycoplasma arthriditis antibodies were detected. Reactivity of serum of adult C57BL/6 female mice with control cells or media (tissue culture, TC) was seen in a significant number of mice. TC reactivity correlated positively with lymphoid perivascular infiltrates, predominantly of the lungs, suggesting an allergic response in development of the lesions. Other lesions of note consisted of Harderian gland inflammation of rats, focal necrotizing lesions of the liver of both species, and thickening of the pleura and adjacent pulmonary interstitium of weanling rats. Embolization of bacteria from the gastrointestinal tract to the liver was considered a possible cause of the liver necrosis in both species. Although lesions of the lung and Harderian gland of the rats are similar to those caused by known viral agents, the cause of the latter could not be determined as these animals were negative for viral antibodies and the former was considered to be related to incomplete pulmonary development in the young rat. Features differentiating the lesions observed in animals of this survey from those caused by viral infection are discussed.

Cardiopulmonary baroreflex control of forearm vascular resistance after acute blood volume expansion.

We report the stimulus-response characteristics of cardiopulmonary (CP) baroreflex control of forearm vascular resistance (FVR) in young adult male volunteers before and after: 1) blood volume expansion (8 ml/kg infusion of 5% human serum albumin solution, n = 5) and 2) a redistribution of blood volume toward the heart (6 degrees head-down tilt (HDT), n = 6). We assessed the relationship between reflex stimulus (i.e., changes in central venous pressure (CVP] and response (i.e., FVR) during unloading of CP mechanoreceptors with lower body negative pressure (0 to -20 mm Hg). Changes in CVP were estimated from changes in venous pressure of a large peripheral vein of the dependent arm with the subject in the right lateral decubitus position. In all conditions, reflex forearm vasoconstriction occurred in response to a reduction in estimated CVP. The absolute change in FVR per unit of CVP was reduced from -4.24 +/- 1.68 to -2.15 +/- 1.16 units/mm Hg (p less than 0.05) following blood volume expansion but was similar before (-3.34 +/- 0.89 units/mm Hg) and during 6 degrees HDT (-3.30 +/- 0.92 units/mm Hg). The reduced sensitivity of the CP baroreflex following volume expansion was manifested primarily as a smaller FVR response to LBNP (p less than 0.05). Blood volume expansion and 6 degrees HDT increased resting estimated CVP by 1.5 and 0.9 mm Hg, respectively (p less than 0.05) and resting levels of FVR decreased slightly.(ABSTRACT TRUNCATED AT 250 WORDS)