Hemodynamic alterations in dogs with shock induced by intravenous injection of heartworm extract.

To elucidate one way of the shock mechanisms, the hemodynamic alterations were examined in 7 dogs with heartworm (HW) extract-induced shock. The first alteration observed after injection of HW extract was a decrease in right ventricular end-diastolic pressure (RVEDP). After that, left ventricular (LV) end-diastolic pressure, LV systolic pressure, and LV dp/dt fell significantly, followed by a decrease in the cardiac output of all dogs to below the detectable level (1.00 l/min). Since RVEDP depends on blood flow into the right ventricle, the decrease in RVEDP means a reduction in venous return. Therefore, this study showed that the first trigger of a decrease in blood pressure in HW extract-induced shock is the reduction in venous return.

Effect of nicardipine and magnesiumon cerebral infarction - brain surface perfusion technique.

The protective effect of pre- and postischemia treatment of the brain by surface perfusion with nicardipine (Nic) and/or magnesium (Mg) was evaluated in a rat focal cerebral ischemia model. Artificial cerebrospinal fluid was perfused into the subarachnoid space of rats, containing Nic or Nic/Mg prior to vessel occlusion and Nic/Mg after occlusion. Reductions in the total amount of glutamate in the microdialysis perfusate and the volume of infarction tissue stained with 2,3,5-triphenyltetrazolium chloride were significant in all treated groups, even in rats treated after ischemia. An additive effect of Mg was also observed. These results suggest that this method may have clinical applications in patients suffering from ischemic insult.

Enantiomer separations by capillary electrochromatography using chiral stationary phases.

The applicability of capillary electrochromatography (CEC) using packed capillary column to enantiomer separations was investigated. As chiral stationary phases, OD type packing materials of 5 and 3 microm particle diameters, originally designed for conventional high-performance liquid chromatography (HPLC) were employed. The chiral packing materials were packed by a pressurized method into a 100 microm I.D. fused-silica capillary. Several racemic enantiomers, such as acidic, neutral and basic drug components, were successfully resolved, typically by using acidic or basic solutions containing acetonitrile as mobile phases. The separation efficiencies for some enantiomers in the chiral CEC system using the 5 microm OD type packing were superior to those obtained in HPLC using chiral packings. The plate heights obtained for several enantiomers were 8-13 microm or the reduced plate height of 1.6-2.6, which indicates the high efficiency of this chiral CEC system.

Eosinophil activation and in situ interleukin-5 production by mononuclear cells in skin lesions of patients with drug hypersensitivity.

In order to determine the inflammatory mechanisms of skin lesions in patients with drug hypersentivity, we examined eosinophil activation and interleukin-5 (IL-5) production in infiltrating lymphocytes. First, we showed that the number of peripheral eosinophils and the level of serum IL-5 at the eruption-active stage were both significantly higher than those in healed skin eruptions. Histological and immunohistological examination revealed that CD4+ T cells and eosinophils significantly more densely infiltrated drug eruptions than control skin lesions. The infiltrating eosinophils were also shown to be activated by immunostaining using anti-secreted formed eosinophilic cationic protein monoclonal antibody. The expression of mRNA for IL-5 in the infiltrating mononuclear cells at drug eruptions was shown by in situ hybridization. These results suggest that infiltrating CD4+ T cells might regulate both peripheral and tissue eosinophils and facilitate allergic inflammation at drug eruptions by means of IL-5 production.

In vitro interleukin-5 (IL-5) production by peripheral blood mononuclear cells from patients with drug hypersensitivity.

It has been shown that CD4+ lymphocytes and eosinophils pathologically infiltrate the dermis in skin eruptions due to hypersensitivity to the administration of certain drugs associated with peripheral eosinophilia. However, the mechanisms involved in drug related skin eruptions with eosinophilia are largely unknown. There are several methods of diagnosing drug hypersensitivity, but no single in vitro method is available for the detection of the sensitizing drug. In order to elicit the mechanism of drug related skin eruption with eosinophilia and to establish effective methods for diagnosing drug hypersensitivity, we studied in vitro IL-5 production by peripheral mononuclear cells (PBMC) from patients with drug related skin eruptions (n = 8). Significant increase in IL-5 from exposure to drug alone (n = 3) and drug with PHA (n = 3) were noted, whereas PBMC from normal subjects (n = 7) exhibited no such stimulation. Six of the eight cases showed a significant decrease in the number of peripheral blood eosinophils when the skin eruptions healed compared with those at the onset. Histopathological features revealed mild to moderate infiltration of eosinophils. Immunohistopathologically, infiltration of CD4+ and CD8+ lymphocytes and CD4+ cells were predominant within the dermis of drug related skin eruption sites in all cases. This study suggested that the IL-5 production of sensitized mononuclear cells might be a critical mediator in drug hypersensitivity with eosinophilia and an important diagnostic marker.

Subclavian artery aneurysm associated with absence of the ipsilateral internal carotid artery.

A 48-year-old male presented with a rare subclavian artery aneurysm associated with absence of the ipsilateral internal carotid artery. The aneurysm was resected and replaced with a Gore Tex artificial graft. Computed tomography, angiography and cerebral blood flow findings suggest that defect of the right internal carotid artery occurred in the developmental stage. There was no past history of trauma, nor histological evidence of inflammatory or sclerotic changes in the aneurysmal wall. The two vascular lesions may have been influenced by a synchronous causative factor in his developmental stage.

Phase effects on the middle and late auditory evoked potentials.

A masking level difference (MLD) paradigm was used to investigate the presence of an electrophysiologic correlate of the psychoacoustic MLD in the middle and late auditory evoked potentials. In experiment 1, middle latency potentials were recorded in six normal-hearing young adults using vertex and temporal electrode montages. Tone bursts of 500 Hz presented in SoNo and Spi No conditions produced no threshold differences that were consistent with an MLD. In experiment 2, late latency potential (P2) thresholds to 500-Hz tone bursts under various phase conditions in noise were measured and compared to behavioral thresholds from the same stimuli. Ten subjects provided behavioral and P2 thresholds to SoNo, S pi No, So N pi S pi N pi, SmNo, and SmNm conditions. The rank order of behavioral and P2 thresholds and MLDs was consistent with previous literature on the behavioral MLD. Cortical contributions were confirmed as necessary for the production of the electrophysiologic MLD and, by analogy, the psychoacoustic MLD.

Binaural phase effects in the auditory brainstem response.

This study investigated the possibility of a correlate of the masking level difference (MLD) in the auditory brainstem response (ABR), given that behavioral data indicate the brainstem origination of the MLD. Previous studies have reported MLD characteristics in the late auditory evoked potentials. In the present study, stimuli were presented in S(o)N(o) and S pi N(o) to female adults with normal hearing. In experiment 1, a binaural phasic difference potential (BPD) was derived by subtracting the suprathreshold ABRs to S(o)N(o) from S pi N(o) for tone pips of 500 to 4000 Hz. The magnitude of the BPD was inversely related to frequency. In experiment 2, thresholds to 500-Hz tone pips in S(o)N(o) and S pi N(o) were equal. In a case study of a subject with no behavioral MLD, the 500-Hz BPD was abnormal on one side, suggesting unilateral interruption of phase synchrony in the brain stem. Thus, the results of this study, in conjunction with previous studies on late potential correlates of the MLD, suggest that the ability to maintain phase information through the brain stem is necessary but not sufficient to generate the MLD.

Clinical and laboratory changes after administration of milbemycin oxime in heartworm-free and heartworm-infected dogs.

Adverse reactions to oral administration of milbemycin oxime were investigated in heartworm (HW)-free and HW-infected dogs given either the minimal HW prophylactic dose (0.25 mg/kg of body weight) or the hookworm anthelmintic dose (0.5 mg/kg). In 12 HW-free control dogs treated with lactose excipient (100 mg/kg), abnormal signs were not observed. There were no differences between the 2 doses in prevalence of clinical signs of disease and laboratory test results. In 60 HW-free dogs (50 dogs administered the low dose, and 10 dogs given the high dose) and 46 nonmicrofilaremic HW-infected dogs (35 dogs administered the low dose, and 11 dogs given the high dose), only a transient and slight paleness of the visible mucous membranes, intestinal hyperperistalsis, or both were observed in some dogs. In 77 microfilaremic (MF) dogs (41 dogs administered the low dose, and 36 dogs given the high dose), weakness or loss of appetite was observed in 13 dogs (16.9%). Paleness of the visible mucous membranes was observed in 16 dogs (20.8%), intestinal hyperperistalsis was observed in 27 dogs (35.1%), and respiratory signs, such as mild labored respiration, were observed in 13 dogs (16.9%). Dullness of heart sounds was noticed in 4 dogs (5.2%). In 12 (9 dogs administered the low dose, and 3 dogs given the high dose) of 89 MF dogs (13.5%), adult heartworms migrated from the pulmonary arteries to the right atrium, causing signs of caval syndrome, including heart murmurs, jugular pulsations, and weakness. In HW-free dogs, rectal temperature tended to decrease gradually, and heart and respiratory rates were transiently decreased.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of cochlear hearing loss on the ABR latencies to clicks and 1000 Hz tone pips.

High-frequency hearing losses can substantially confound the interpretation of click-evoked auditory brainstem responses (ABRs). One method proposed to circumvent the problem is to use frequency-specific tone pips to stimulate equivalent areas on the basilar membrane in normal and pathologic groups, or in both ears of asymmetrically impaired patients. This retrospective study investigated the ABRs to clicks and 1000-Hz tone pips from 90 asymmetrically impaired subjects with cochlear pathology. The 4000 Hz threshold significantly affected the wave V latencies from both clicks and tone pips for the most severely impaired subjects. The wave V latencies were highly correlated between ears for both stimuli, but the correlation was higher with the 1000-Hz tone pips. It was concluded that the use of 1000-Hz tone pips can supplement the interpretation of click-evoked ABRs, particularly in patients whose 2000- and/or 4000-Hz thresholds are worse than 75 dB HL.

Effects of noise bandwidth on the late-potential masking level difference.

The masking level difference (MLD) is a psychoacoustic phenomenon derived from the subtraction of S pi No thresholds (signals pi radians out of phase and noise in phase at the two ears) from SoNo thresholds (signals and noise in phase at the two ears). The purpose of this study was to determine if the MLD derived from the late components (P1, N1, P2, N2) of the auditory evoked potentials was a physiological correlate of the behavioral MLD. Subjects were 15 young adults with normal hearing. Comparisons were made between behavioral and late potential thresholds to 500 Hz stimuli in So and S pi conditions in quiet, and to 500 Hz stimuli in SoNo and S pi No conditions in narrow band (50 Hz) and wide band (600 Hz) noise. No significant differences were seen for behavioral or late-potential thresholds to So and S pi conditions. The S pi No thresholds was significantly lower than the SoNo threshold, yielding an MLD for both the behavioral and physiological responses. The magnitudes of both the behavioral and late-potential MLD were larger with the narrow band noise than with the wide band noise. Evidence, therefore, is provided that the late-potential MLD reflects similar processes as are responsible for the behavioral MLD.

The late auditory evoked potential masking-level difference as a function of noise level.

The purpose of this study was to determine whether the masking-level difference (MLD) obtained with the late (P2) auditory evoked potentials has characteristics similar to those reported for the behavioral MLD with respect to the effects of noise level. Psychoacoustic studies have shown that the magnitude of the MLD increases as a function of the noise level. In the present study, P2 thresholds were measured in SoNo (signals and noise in phase at the ears) and S pi No (signals out of phase and noise in phase at the ears) conditions for noise levels of 0-60 dB pressure spectrum level (Lps). Subjects were 5 normal-hearing young adults. The difference in SoNo and S pi No thresholds, or the MLD, increased linearly as the noise levels increased through 60 dB Lps, whereas the behavioral MLD magnitude is reported to saturate at high noise levels. These results suggest that the late-potential MLD reflects characteristics similar to, but not identical with, those of the behavioral MLD.

Colangite aguda: infecçäo biliar obstrutiva / Acute cholangitis: obstructive biliary infection

Os autores procuram demonstrar atraves de exames histopatologicos da via biliar principal, na vigencia da assim chamada "colangite aguda obstrutiva", a ausencia de lesoes da parede do coledoco com caracteristicas de processo inflamatorio agudo. Fazem estudo comparativo de obito recente, com fragmentos tomados durante operacoes realizadas em seis doentes com sepsis biliar obstrutiva aguda, o que comprova o fato