Effect of heat treatment and enzymatic digestion on the B cell epitopes of cow's milk proteins.

BACKGROUND: Processing milk leads to changes in clinical allergenicity. However, the mechanism by which heat treatment affects the allergenicity of milk proteins is not fully understood. OBJECTIVE: We investigated the effect of heat treatment and enzymatic digestion on the allergenicity of B cell epitopes of milk proteins using a histamine release assay. METHODS: Human basophils were passively sensitized using sera from 10 patients with allergies to cow's milk. All the patients experienced symptoms immediately after ingesting milk. The human basophils were obtained from umbilical cord blood mononuclear cells after culturing the mononuclear cells for 3-4 weeks in the presence of IL-3. After sensitization with 10% patient sera for 48 h, the cells were stimulated with untreated, heat-treated, or heat-treated and pepsin-and-trypsin-digested beta-lactoglobulin or alpha-casein for 1 h. The histamine concentrations in the supernatants were then measured by radioimmunoassay. RESULTS: Heat treatment alone did not alter the molecular weight of beta-lactoglobulin or alpha-casein. Heat treatment of beta-lactoglobulin significantly increased its susceptibility to enzymatic digestion in a time- and temperature-dependent manner and reduced its ability to induce histamine release from sensitized basophils. Similar findings were not observed for alpha-casein. The combination of heat treatment and enzymatic digestion reduced the abilities of both beta-lactoglobulin and alpha-casein to induce histamine release from passively sensitized basophils. CONCLUSIONS: Heat treatment reduced the allergenicity of beta-lactoglobulin by inducing conformational changes and by increasing its susceptibility to enzymatic digestion, both of which disrupted B cell epitopes, whereas heat treatment alone did not alter the allergenicity of alpha-casein.

[The diagnostic significance of immediate and late-phase skin reactions in patients with atopic dermatitis in early infancy].

The diagnostic significance of immediate reaction (IR) and late-phase skin reaction (LPR) in early infancy was evaluated. Twenty six infants aged 3 months, with atopic dermatitis, received an intracutaneous test injection of egg white extract or control solution. Total serum IgE levels, peripheral eosinophile counts, CAP-RAST scores, and lymphocyte stimulation tests (LST) with egg white extract were measured. Infants were tested and followed every 3 months up to 12 months of age. There was a significant relationship between the diameter of IR elicited by intracutaneous injection of egg white extract and total serum IgE levels (p < 0.01). The diameters of IR and the diameters of LPR did not correlate. In some cases, flares over 10 mm appeared 15 minutes after injection of control solution. The average serum IgE level in the IR-positive group tended to be higher than that in the IR-negative group but this difference was not statistically significant. The stimulation index (SI) of LST in the LPR-positive group was significantly higher than that in the control group (p < 0.05). In the RAST-positive group more cases had the acute symptoms provoked by egg ingestion at 12 months of age as compared to the RAST-negative group (p < 0.05). And in the IR-positive group also more cases had the symptoms than in the IR-negative group (p < 0.01). For infants aged 3 and 6 months the number of cases with positive RAST scores following injection of egg white extract was significantly higher in the IR-positive group than in the IR-negative group (p < 0.005, p < 0.05). There was no significant difference of the RAST positive ratio between the LPR-positive and the LPR-negative group. At 6 months of age, there were more cases with positive RAST scores in the IR- and/or LPR-positive group than in the group negative for both (p < 0.05). In the LPR-positive group more cases had symptoms of allergic bronchitis or bronchial asthma before 12 months of age as compared to the LPR-negative group (p < 0.005).

Bupivacaine inhibits baroreflex control of heart rate in conscious rats.

BACKGROUND: Because exposure to intravenously administered bupivacaine may alter cardiovascular reflexes, the authors examined bupivacaine actions on baroreflex control of heart rate in conscious rats. METHODS: Baroreflex sensitivity (pulse interval vs. systolic blood pressure in ms/mmHg) was determined before, and 1.5 and 15.0 min after rapid intravenous administration of bupivacaine (0.5, 1.0, and 2.0 mg/kg) using heart rate changes evoked by intravenously administered phenylephrine or nitroprusside. The actions on the sympathetic and parasympathetic autonomic divisions of the baroreflex were tested in the presence of a muscarinic antagonist methyl atropine and a beta-adrenergic antagonist atenolol. RESULTS: Within seconds of injection of bupivacaine, mean arterial pressure increased and heart rate decreased in a dose-dependent manner. Baroreflex sensitivity was unaltered after administration of 0.5 mg/kg bupivacaine. In addition, 1 mg/kg bupivacaine at 1.5 min depressed phenylephrine-evoked reflex bradycardia (0.776 +/- 0.325 vs. 0.543 +/- 0.282 ms/mmHg, P < 0.05) but had no effect on nitroprusside-induced tachycardia. Bupivacaine (2 mg/kg), however, depressed reflex bradycardia and tachycardia (phenylephrine, 0.751 +/- 0.318 vs. 0.451 +/- 0.265; nitroprusside, 0.839 +/- 0.256 vs. 0.564 +/- 0.19 ms/mmHg, P < 0.05). Baroreflex sensitivity returned to prebupivacaine levels by 15 min. Bupivacaine (2 mg/kg), in the presence of atenolol, depressed baroreflex sensitivity (phenylephrine, 0.633 +/- 0.204 vs. 0.277 +/- 0.282; nitroprusside, 0.653 +/- 0.142 vs. 0.320 +/- 0.299 ms/mmHg, P < 0.05). In contrast, bupivacaine did not alter baroreflex sensitivity in the presence of methyl atropine. CONCLUSIONS: Bupivacaine, in clinically relevant concentrations, inhibits baroreflex control of heart rate in conscious rats. This inhibition appears to involve primarily vagal components of the baroreflex-heart rate pathways.

[Atopic dermatitis in early infancy in Matuyama city: prevalence and seasonal variations].

From Jun 1996 to May 1999, 1280 infants were examined by the author 6 times from birth to 12 month-old in each 0, 1, 3, 6, 9, 12 month-old time at NTT Nishinihon Matuyama Hospital. The 12-month cumulative prevalence of AD was 28.5%. Out of the cases 82.2% showed the symptoms before 3 month-old. There were 217 male infants in AD group (59.5%). This percentage was significantly higher than 45.2% in non-AD group (p < 0.001). Approximately 70% cases in AD group had family history of allergic diseases. This ratio was significantly higher compared to 49.6% in non-AD group (p < 0.001). According to the season of birth, there were significant differences in the 12-month cumulative prevalence of AD (p < 0.005). Infants born in the spring, summer, autumn and winter showed 21.1%, 27.2%, 31.3%, and 33.9% of cumulative prevalence of AD respectively. The prevalence of AD at 3 month-old and the ratio that the symptoms appeared before 3 month-old also had similarly significant tendency (p < 0.001) (Infants born in the spring showed 15.4% and 73%. Infants born in the winter showed 31.5% and 92.9%). There were no relationship between the cumulative prevalence of AD and the precipitation.

Adrenergic activation confers cardioprotection mediated by adenosine, but is not required for ischemic preconditioning.

BACKGROUND: The aim of this study was to determine whether (1) adrenergic activation is cardioprotective, (2) adrenergic cardioprotection occurs via adenosine receptor activation, and (3) ischemic preconditioning requires alpha-adrenergic activation. METHODS: Anesthetised open chest rabbits underwent 30 min coronary occlusion and 3 h reperfusion. Ischemic preconditioning was elicited with 5 min coronary occlusion and 10 min reperfusion. Activation of adrenergic receptors with endogenous norepinephrine was achieved with tyramine (0.28 mg/kg/min intravenously for 5 min). Adenosine receptors were blocked with 8-p-sulfophenyl theophylline (10 mg/kg intravenously), alpha 1-adrenergic receptors were selectively blocked with prazosin (0.1 mg/kg intravenously), and alpha-adrenergic receptors were blocked with phentolamine (4 mg/kg intravenously). RESULTS: Ischemic preconditioning reduced risk-adjusted infarct volume by 79% (P < 0.0005). This protection was attenuated by adenosine receptor blockade. Tyramine infusion resulted in a 1305% change from baseline plasma norepinephrine concentration (P < or = 0.01), and reduced infarct volume by 55% (P = 0.01). Adenosine receptor blockade abolished this protection. Blockade of alpha 1-adrenergic receptors with prazosin failed to abolish ischemic preconditioning (79 versus 89% reduction in infarct volume, without and with prazosin, respectively). Similarly, non-selective blockade of alpha-adrenergic receptors also failed to abolish ischemic preconditioning (79 versus 57% reduction without and with phentolamine, respectively). CONCLUSIONS: We conclude that the cardioprotection of ischemic preconditioning and alpha-adrenergic activation both involve adenosine, but ischemic preconditioning does not require alpha-adrenergic activation.

Anaesthetics alter the magnitude of infarct limitation by ischaemic preconditioning.

OBJECTIVE: The aim was to determine whether three commonly used animal anaesthetics alter the magnitude of infarct limitation achieved with ischaemic preconditioning. METHODS: Eighty four anaesthetised non-preconditioned and preconditioned open chest rabbits underwent a 30 min coronary occlusion followed by 3 h reperfusion. Ischaemic preconditioning was achieved with 5 min coronary occlusion beginning 15 min before the 30 min coronary occlusion. The anaesthetics studied were: pentobarbitone (30 mg.kg-1 intravenously +30-50 mg.kg-1.h-1 intravenously), isoflurane (1.5-2.5% end expiratory), and ketamine/xylazine (cocktail of 67 mg ketamine and 6.7 mg xylazine.ml-1, 1 ml.kg-1 intramuscularly +0.3-1.3 ml.kg-1.h-1 intramuscularly). Area at risk was delineated with ZnCdS particles and infarction assessed with tetrazolium. RESULTS: There were no significant differences in area at risk, heart rate, arterial pressure, and temperature between non-preconditioned and preconditioned hearts. Although infarct size was not significantly different among non-preconditioned hearts for each anaesthetic regimen (p = NS), the magnitude of infarct limitation with preconditioning varied with the anaesthetic employed (decrease in infarct size from control values of 81%, 44%, and 33% for pentobarbitone, isoflurane and ketamine/xylazine, respectively, p = 0.0145 for comparison of the three magnitudes, two factor ANOVA). CONCLUSION: Anaesthetic regimens affect the degree of infarct size limitation seen with ischaemic preconditioning.

[Ritodrine induced pulmonary edema after caesarean section for a triplet pregnancy].

Selective beta-sympathomimetic drugs are frequently used for tocolysis. But, since these drugs exhibit some beta-1 activity as well, they may bring about pulmonary edema, myocardial ischemia, cardiac arrhythmia and others as side effects. A 29 year-old female with a triplet pregnancy had premature contraction at 26 weeks of gestation. High doses of IV ritodrine were given for tocolysis for 8 weeks until caesarean section. One hour after caesarean section at 35 weeks of gestation, she complained of dyspnea. Urinary output decreased and chest X-ray showed pulmonary edema. She was intubated and artificial ventilation with PEEP was performed in ICU. Echocardiogram showed left ventricular dilatation. ECG showed inverted T waves on all leads. We diagnosed her as suffering from acute heart failure, pulmonary edema and acute renal failure. Hemodialysis was performed for 6 hrs but PCWP was still 18 mmHg. So CVVH was added to hemodialysis. Five hrs after the start of CVVH, her symptoms gradually started to subside. Total fluid removal was 5.8 l over 16 hrs. Three days after admission she was extubated and five days later returned to her ward. We concluded that pulmonary edema, heart failure and renal failure were induced by the long-term high dose medication of ritodrine, resulting in volume overload and myocardial dysfunction.

Anticipation in hereditary dentatorubral-pallidoluysian atrophy.

Anticipation refers to the progressively earlier onset and increase in disease severity in successive generations. We studied four families with hereditary dentatorubral-pallidoluysian atrophy (DRPLA), a neurodegenerative disease, and anticipation was present in the mode of inheritance. In subsequent generations DRPLA shows an earlier onset and more severe as well as additional symptoms. Older onset patients suffer from cerebellar ataxia with or without dementia, whereas younger onset patients present as progressive myoclonus epilepsy syndrome, which consists of mental retardation, dementia, and cerebellar ataxia as well as epilepsy and myoclonus. Anticipation with paternal transmission was significantly greater than with maternal transmission.

Cardioprotection provided by adenosine receptor activation is abolished by blockade of the KATP channel.

Adenosine agonists and openers of the ATP-sensitive potassium (KATP) channel have been reported to limit infarct size (IS). We tested the hypothesis that these phenomena are interdependent. Anesthetized swine underwent 60 min of coronary artery occlusion and 90 min of reperfusion. Preconditioning was elicited by two cycles comprising 10 min of occlusion and 10 min of reperfusion (n = 7 swine). An intracoronary infusion of adenosine (Ado; n = 10) or (-)-N6-(2-phenylisopropyl)-adenosine (R-PIA; n = 7) replaced preconditioning ischemia. KATP channels were blocked with sodium 5-hydroxydecanoate (5-HD) in the absence (n = 6) or presence (n = 8) of R-PIA. Control pigs (n = 7) received saline vehicle. IS was assessed with tetrazolium and normalized as percentage of area at risk. Preconditioning resulted in a reduced IS compared with Control (3.9 +/- 1.8 vs. 43.5 +/- 6.9%, respectively; P < 0.0005). Ado and R-PIA also reduced IS [21.1 +/- 6.8 (P < 0.01) and 11.2 +/- 7.4% (P < 0.005), respectively]. 5-HD alone did not alter IS, but it abolished R-PIA-induced cardioprotection (IS 5-HD + R-PIA = 48.6 +/- 13.2%). Thus Ado A1-receptor agonists mimicked the cardioprotection of ischemic preconditioning. The Ado-induced limitation of IS was abolished by blockade of the KATP channel. We conclude that both Ado A1 receptors and KATP channels may be involved in ischemic preconditioning.

An analysis of flow volume curves during artificial ventilation.

Expiratory flow-volume curves during artificial ventilation (FV-av) were analyzed in 48 patients undergoing general anesthesia. They were divided into 4 groups according to preoperative respiratory disorders; obstructive type (group 1), restrictive type (group 2), small airway disease (group 3) and normal control (group 4). Expiratory flow rates and volumes during artificial ventilation were plotted on an X-Y recorder to calculate V50/V25, mean time constant ratio (MTCR), obstructive index (OI) and slope ratio (SR). FV-av values were compared among groups. FV-av values in groups 2 were significantly higher than those in group 4. The values in group 1 and those in group 3 were not significantly different from those in group 4. FV-av values may reflect restrictive respiratory dysfunctions but they are not sensitive enough to detect obstructive lung disease.

A new model for total cerebral ischemia in dogs.

We have developed a new method producing total cerebral ischemia (TCI) in dogs; clamping ascending aorta with aorto-atrial bypass formation. Clamping ascending aorta provides TCI, the duration of which can be controlled up to the periods of 10 min. Beyond this interval, it is difficult to maintain TCI because of heart failure from high afterload. Blood outflow from left ventricle is completely obstructed except for coronary circulation which is small relative to the blood volume expelled from left ventricle, even if venous return to the heart is reduced. Aorto-atrial bypass formation during aortic clamping provides two distinctive advantages. First, adjusting aortic pressure in an appropriate level low enough not to overload myocardium but still high enough to maintain sufficient coronary blood flow is possible by regulating the blood flow through the bypass tubing, and secondly drug administration and blood volume control is possible through the tubing. These result in better preservation of myocardium, enabling longer TCI and longer survivals after TCI. We were successful in having up to 18 min of TCI with this method. Seventy-five percent of dogs of 12 min TCI and 40% of 15 min TCI survived 7 days, limit of experiment, after TCI, but no dogs of 18 min TCI survived for more than 3 days.

Transient hyperdense cerebral areas in childhood leukemia: CT demonstration.

A child with acute myeloblastic leukemia and severe central nervous system complications during remission showed diffuse cerebral high density areas in a CT examination. These areas disappeared completely over the following few months. The possible causes for this phenomenon are discussed.