Anatomical and functional connectivity of the transected ulnar nerve after intercostal neurotization in cats

OBJECT

Acute transfer of three intercostal nerves to the ulnar nerve was performed in cats for histological and clinical evaluation of a distal muscle reinnervation.

METHODS

Infraclavicular intercostal-ulnar communications were created after dividing the motor branches of the upper intercostal nerves in 14 adult cats. Reinnervation of distal forelimb muscles in the ulnar territory was assessed by electromyographic (EMG) studies and motor function rating each month until 18 months postsurgery. In five of these treated animals, and in tour controls, horseradish peroxidase (HRP) was applied to the ulnar or intercostal nerves to study the amount and distribution of retrograde motor neuron labeling in the spinal cord. Also, samples of reinnervated muscles and neurotized ulnar nerves were processed to assess regeneration. Simple ulnar transection without reconstruction led to permanent atrophy of ulnar muscles, lack of recovery according to EMG or clinical studies, and disappearance of the ulnar motor neuron pool. In contrast, ulnar neurotization with the intercostal nerves led to a high rate of functional recovery, which began 5 months postsurgery, and progressed from muscle activity synchronized with ventilatory movements to spontaneous movements that were independent of respiration. This recovery was accompanied by substantial retrograde labeling of intercostal motor neurons after HRP application in the ulnar nerve. Cell counts showed that practically the whole motor neuron pool of the involved intercostal nerves contributed to reinnervation of the transected ulnar nerve.

CONCLUSIONS

These findings demonstrate that the use of intercostal nerves to neurotize long brachial plexus nerves can achieve long-lasting and successful reinnervation of distal forelimb muscles.

Maximal response plateau to methacholine as a reliable index for reducing inhaled budesonide in moderate asthma

Although some studies suggest that asthma deteriorates after reducing inhaled steroids, results of long-term studies indicate that this might not be true for all patients. The aim of this study was to determine the utility of the detection of a plateau on the concentration-response curves to inhaled methacholine as a marker for safely reducing the dose of inhaled budesonide in asthmatic patients who are well-controlled with a moderately high dose of this inhaled steroid. A total of 46 patients with moderate asthma, well-controlled for at least 6 months by treatment with 800 microg budesonide daily, were included in the study. Subjects were treated for a 2-week run-in period with their usual dose of budesonide. At the end of the run-in, all subjects were challenged with methacholine (0.095-200 mg x mL(-1)). Plateau responses, median effective concentration values, slopes and provocative concentration of methacholine causing a 20% fall in forced expiratory volume in one second (FEV1) values were measured. For the subsequent 12 weeks, patients were treated in an open design with budesonide at a reduced dose (200 microg once daily), and were asked to record their peak expiratory flow (PEF) in the morning and in the evening. In addition, asthma symptoms and use of rescue terbutaline were recorded in diaries. Plateaus were present in 24 patients, whereas 22 subjects showed concentration-response curves without evidence of a plateau. Ten patients in the nonplateau group deteriorated after reducing inhaled budesonide, compared to one patient in the plateau group (p = 0.002). In the nonplateau group, FEV1 decreased from a baseline value of 3.28+/-0.19 L to 2.94+/-0.20 L at week 12 (p<0.0001). Likewise, morning PEF decreased from 419+/-19 L x min(-1) at baseline to 394+/-19 L x min(-1) at week 12 (p = 0.02). By contrast, these variables remained unchanged in the plateau group. In conclusion, in asthmatic patients, well-controlled with a moderately high dose of budesonide, the detection of a plateau on the concentration-response curve to inhaled methacholine may be used as a marker for safely reducing the corticosteroid dose.

A quantitative study of changes in the human corpus luteum microvasculature during the menstrual cycle

Endothelial cells are the most abundant cell type in the corpus luteum (CL), and changes in blood vessels have been proposed to play a pivotal role in CL regression. We have studied quantitatively the changes in the human granulosa-luteal microvasculature in CL of various ages: young (Days 17-19 of the cycle), mature (Days 20-24), old (Days 25-27), early regressing (follicular phase of the following cycle), and late regressing (luteal phase of the following cycle). Blood vessels were identified by immunohistochemical staining for the endothelial cell marker CD34. Because of the anisotropy of blood vessels, both vertical and transverse sections of the granulosa-lutein layer (GLL) were used to estimate relative (volume, surface, and length densities) and absolute (mean cross-sectional area) vascular variables. Full luteinization from young to mature CL was accompanied by a 61% increase in the mean cross-sectional area of vascular profiles and a 52% increase in the mean volume of granulosa-lutein cells, as an estimator of changes in the volume of the GLL. In old and early regressing CL, there was a progressive increase in relative structural vascular variables, due to the shrinkage of the GLL, whereas the mean cross-sectional area of capillaries showed a 53% decrease from mature to old CL. Finally, in late regressing CL, there was a decrease in most relative structural variables, in spite of the increasingly shrunken GLL. The decrease in the capillary diameter found at the late luteal phase most likely leads to a decreased blood flow, and early changes in blood vessels could initiate and/or accelerate CL regression.

Existence of junction-like structures in large B-cell non-Hodgkin's lymphomas. An ultrastructural study

The purpose of this work is to study the presence of cell junction-like structures in large B-cell lymphomas. The ultrastructural study, based on 20 cases of this entity proved by immunohistochemistry and flow cytometry, demonstrated four types of junction-like devices easily found between tumor cells. Several explanations are offered about the possible nature of such structures, including the possibility of them being the result of adhesion phenomena. It should also be emphasized that they can potentially complicate the differential diagnosis of those neoplasms. We should, therefore, be careful in rejecting an ultrastructural diagnosis of large B-cell lymphoma based only on the presence of junction-like structures.

Datura metel: in vitro production of tropane alkaloids

Hairy root lines of Datura metel were established following infection of aseptic stem segments with Agrobacterium rhizogenes strain A4 and cultured in hormone-free B5 solid medium. The growth and production of hyoscyamine and scopolamine (mg/g dry wt.) of these root cultures was encouraged by using B5 liquid medium with half-strength salts. In these culture conditions, the capacity of the highest productive root line 25 to excrete scopolamine into the culture medium rose from 8.7% to 70% when the permeabilizing agent Tween 20 was added for 24 h to the medium, after 2 and 4 weeks of culture. Using an airlift bioreactor (41) with modifications in order to increase root anchorage, the Tween 20 treatment encouraged both growth and alkaloid productivity of cultured root line 25. After 4 weeks their biomass yield was 2.3 mg/l/day and 0.84 mg/l/day of scopolamine was produced (70% extracellular). The scopolamine released into the culture medium was separated with an Amberlite XAD-2 column located in the media exit.

Notochord involvement in experimental esophageal atresia

Esophageal atresia (EA) is often accompanied by vertebral defects and other anomalies. The adriamycin rat model of EA has disclosed the embryology of the malformation and shown that the vertebrae and notochord are also abnormal. This study describes the nature of notochord malformations in rat embryos exposed to adriamycin. Time-mated rats received either 1.75 mg/kg adriamycin or vehicle i.p. on gestational days (E) 6 to 9; E-12, E-12.5, and E-13 embryos were harvested, embedded in paraffin, and serially sectioned at 3 microm in transverse plane from the head to the stomach for subsequent PAS staining. The findings in both groups were compared at the three endpoints. Control embryos had neither tracheoesophageal nor notochord malformations. On day 12, only 11/36 adriamycin embryos were normal; 7/36 had abnormal notochords, 11/36 had EA, and 7/36 had both. The corresponding figures for 12.5 days were 12/27, 0/27, 7/27, and 8/27 and those for the day 13 7/23, 5/23, 3/23, and 8/23. The malformed notochords were thickened, bifurcated, or trifurcated in the sagittal plane. The simultaneous presence of notochord and esophageal malformations suggests a direct link between both defects, but our observation of isolated occurrence of both shows that they reflect two expressions of the profound disturbance of embryonic para-axial organization responsible for the cluster of malformations rather than a cause-effect association.

Iridoids from Lippia graveolens

An investigation of the leaves of Lippia graveolens from Guatemala provided 10 iridoid and secoiridoid glucosides as well as their ester derivatives. Minor constituents were loganin, secologanin, secoxyloganin, dimethylsecologanoside, loganic acid, 8-epi-loganic acid and caryoptoside. Major constituents were the novel iridoids caryoptosidic acid and lippioside I and II consisting of caryoptosidic acid esterified at the C-6 position of glucose with p-coumaroyl or caffeoyl residues, respectively. Their structures were mainly elucidated by NMR spectroscopy.

Dexamethasone rapidly regulates TRH mRNA levels in hypothalamic cell cultures: interaction with the cAMP pathway

The biosynthesis of thyrotropin-releasing hormone (TRH) in the hypothalamic paraventricular nucleus (PVN) is subject to neural and hormonal regulations. To identify some of the potential effectors of this modulation, we incubated hypothalamic dispersed cells with dexamethasone for short periods of time (1-3 h) and studied the interaction of this hormone with protein kinase C (PKC) and PKA signaling pathways. TRH mRNA relative changes were determined by the RT-PCR technique. One hour incubation with 10(-10)-10(-4) M dexamethasone produced a concentration-dependent biphasic effect: an inhibition was observed on TRH mRNA levels at 10(-10) M, an increase above control at 10(-8)-10(-6) M and a reduction at higher concentrations (10(-5)- 10(-4) M). The stimulatory effect of 10(-8) M dexamethasone on TRH mRNA was essentially independent of new protein synthesis, as evidenced by cycloheximide pretreatment. Changes in TRH mRNA levels were reflected by enhanced TRH cell content. Incubation with a cAMP analogue (8-bromo-cAMP, 8Br-cAMP) or with a PKC activator (12-O-tetradecanoylphorbol-13-acetate, TPA) increased TRH mRNA levels after 1 and 2 h, respectively. An increase in TRH mRNA expression was observed by in situ hybridization of dexamethasone or 8Br-cAMP-treated cells. The interaction of dexamethasone, PKA and PKC signaling pathways was studied by combined treatment. The stimulatory effect of 10(-7) M TPA on TRH mRNA levels was additive to that of dexamethasone; in contrast, coincubation with 10(-3) M 8-Br-cAMP and dexamethasone diminished the stimulatory effect of both drugs. An inhibition was observed when the cAMP analogue was coincubated with TPA or TPA and dexamethasone. These results demonstrate that dexamethasone can rapidly regulate TRH biosynthesis and suggest a cross talk between cAMP, glucocorticoid receptors and PKC transducing pathways.

Pharyngeal branchial cyst: magnetic resonance findings

An unusual case of pharyngeal cyst in a 25-year-old man studied by Magnetic Resonance (MR) is described. Anatomic location and pathological findings indicated the second branchial pouch origin.

Both prolactin and progesterone in proestrus are necessary for the induction of apoptosis in the regressing corpus luteum of the rat

This study was conducted to analyze the roles of prolactin (PRL) and progesterone in the induction of luteal cell apoptosis and accumulation of macrophages in the regressing corpus luteum. We studied the number of apoptotic cells and macrophages in regressing corpora lutea in estrus 1) in cycling rats or after blocking PRL secretion with the dopaminergic agonist CB154, and 2) after blocking progesterone actions with the progesterone receptor antagonists RU-486 or ZK98299. Cells showing the morphological features characteristic of apoptosis contained fragmented DNA as indicated by in situ 3' end labeling. In cycling rats, a 100-fold increase in the number of apoptotic cells and a 4-fold increase in the number of macrophages was found from the evening (1600 h) of proestrus to the morning (1100 h) of estrus. Both increases were blocked by PRL suppression with CB154. Furthermore, blocking progesterone actions with progesterone receptor antagonists RU-486 or ZK98299 without affecting PRL secretion inhibited apoptosis but did not affect the accumulation of macrophages, whether treatment was started on the morning of metestrus (blocking diestrous and proestrous progesterone) or on proestrus (blocking only proestrous progesterone). Otherwise, exogenous progesterone was not effective in inducing apoptosis in the absence of PRL. These results indicate that both PRL and progesterone in proestrus are necessary for the induction of apoptosis in the regressing corpora lutea, whereas the accumulation of macrophages seemed to be dependent exclusively on the PRL surge.

Comparison of the effects of ACE inhibition with those of angiotensin II receptor antagonism on systolic and diastolic myocardial stunning in isolated rabbit heart

The aim was to determine whether enalaprilat (0.08 mg/kg/min) or losartan (0.01 mg/kg/min) administration before ischemia can improve postischemic systolic and diastolic dysfunction ('stunned myocardium') and attenuate the 'hyperfunction' phase at the beginning of reperfusion. An isolated isovolumic rabbit heart preparation was subjected to 15 min of ischemia followed by 30 min of reperfusion without (group 1) or with pretreatment with enalaprilat (group 2) or losartan (group 3). Left ventricular developed pressure and end-diastolic pressure (diastolic stiffness) were measured and the time constant of isovolumic relaxation (T, Tau) and the ratio between +dP/dt and -dP/dt were calculated. In comparison to the stunned group (group 1) both enalaprilat (group 2) and losartan (group 3) exerted a significant protective effect on postischemic recovery of contractile state and diastolic stiffness. Only enalaprilat attenuated the 'hypercontractile' phase. However, both enalaprilat and losartan failed to improve myocardial relaxation. In summary, these data strongly suggest a direct deleterious action of the local renin-angiotensin system on ischemic myocardium and diminution of myocardial stunning with its successful blockade. Although, we can not exclude the possibility that bradykinin has some cardioprotective effect, these data suggest that angiotensin exacerbates myocardial injury.

Peak flow variability and sputum eosinophilia in allergic rhinitis

BACKGROUND

Although some non-asthmatic subjects with allergic rhinitis exhibit airway hyperresponsiveness and increased diurnal peak expiratory flow (PEF) variation, little is known about the critical features that determine these physiologic alterations.

OBJECTIVE

In subjects with allergic rhinitis and methacholine hyperresponsiveness but no asthma symptoms, we examined whether there were features of asthmatic airway inflammation.

METHODS

Forty non-asthmatic adults (11 with allergic rhinitis and methacholine hyperresponsiveness, 20 with allergic rhinitis and normal methacholine responsiveness, and 9 healthy control subjects) were studied. Sputum was induced with inhaled hypertonic saline for 5-minute periods for up to 20 minutes. Plugs from the lower respiratory tract were selected for differential counting in cytocentrifuged preparations. For the next 14 days, subjects measured their PEF two times daily. Peak expiratory flow variation was expressed as amplitude % mean.

RESULTS

Peak expiratory flow variation was significantly higher in subjects with allergic rhinitis and methacholine hyperresponsiveness than in allergic rhinitis patients with normal methacholine responsiveness and healthy controls. Eosinophil counts in the induced sputum were significantly higher in the subjects with allergic rhinitis and methacholine hyperresponsiveness [median (interquartile range), 7.3 (9.0)%] compared with allergic rhinitis patients with normal methacholine responsiveness [2.5 (3.8)%, P = .03] and healthy controls [1.0 (1.0)%, P = .02].

CONCLUSION

We conclude that eosinophilic inflammation may be present in subjects with allergic rhinitis and airway hyperresponsiveness even when there are no symptoms of asthma. This could indicate that bronchial eosinophilia is insufficient to cause asthmatic symptoms.

Macrophages, cell proliferation, and cell death in the human menstrual corpus luteum

We studied the presence and numbers of macrophages in the different compartments of the human menstrual corpus luteum (CL) in relation to the proliferative activity and apoptosis in luteal cells. Macrophages were recognized by immunohistochemical demonstration of the lysosome-associated glycoprotein CD68, and proliferating cells by immunohistochemical detection of the cell cycle-related protein Ki67 and by counting mitotic cells. In general, changes in the number of macrophages were parallel to the functional activity of the CL. Macrophage numbers increased up to the end of the early luteal phase, remained relatively unchanged during the midluteal phase, and decreased at the late luteal phase. Furthermore, macrophages showed prominent morphological changes during the cycle. They showed round or elongated cytoplasm during the early and late luteal phases, and dendritic features in the midluteal phase. Proliferating cells were very abundant on Days 15-16 and showed a significant decrease thereafter. Most proliferating cells corresponded to stromal (mainly vascular) cells. However, about 5% of granulosa-lutein cells and about 15% of theca-lutein cells were proliferating during the early and midluteal phases. Regression of the CL at the late luteal phase was associated with both a decrease in the number of proliferating cells and an increase in the number of apoptotic cells, which were highly increased on Days 25-27 of the cycle. The number of macrophages was not related to cell proliferation nor to cell death during the luteal phase. The observed changes in both macrophage number and morphology suggest the existence of a bidirectional communication between macrophages and steroidogenic cells in the human CL, or regulation of both cell populations by similar mechanisms.

[Effect of enalaprilat on postischemic systolic and diastolic dysfunction (stunned myocardium) on the isolated rabbit heart]

The aim was to determine: 1) whether Enalaprilat (0.08 mg/kg/min) administration: a) before ischemia or b) at the beginning of reperfusion improved the postischemic systolic and diastolic dysfunction ("stunned myocardium") and attenuated the "hyperfunction" phase at the beginning of reperfusion; and 2) whether creatine kinase (CPK), and lactate dehydrogenase (LDH) activities, and lactate release are involved in the protective effects of Enalaprilat. An isolated isovolumic rabbit heart preparation was used as experimental model and subjected to 15 minutes of ischemia followed by 30 minutes of reperfusion, without (group 1), and with Enalaprilat before the ischemia (group 2) and at the beginning of reperfusion (group 3). Left ventricular developed pressure, and end diastolic pressure (diastolic stiffness) were measured and the time constant of isovolumic relaxation (t, Tau) and the ratio between +dP/dtmax and -dP/dtmax were calculated. For the determinations of lactate release and CPK and LDH activities in the perfusate, samples were taken from the coronary effluent for spectrophotometrical measurements. In comparison to the stunned group (group 1) both Enalaprilat preischemia (group 2) and postischemia (group 3) exerted a significant protective effect on the postischemic recovery of contractile state and diastolic stiffness, and attenuated the "hypercontractile" phase in both groups. However Enalaprilat failed to improve myocardial relaxation. Lactate release was also attenuated, but the enzyme activities were not modified.

A comparative study of mast cells and eosinophil leukocytes in the mammalian testis

The existence of a physiological integration between the immune and endocrine systems has long been recognized. In spite of the abundant literature data on the presence of cells of the immune system in the testis, mast cells and eosinophil leukocytes have received little attention. We have studied the presence, distribution and numbers of mast cells and eosinophils in the testes of 12 mammalian species. Mast cells were frequently found in equine (stallion, ass and mule) and human testis, whereas eosinophils were nearly absent. On the contrary, eosinophils were abundant in the hare testis, while mast cells were lacking. Both cells types were present in high numbers in swine (wild and domestic boar) testis. Otherwise, mast cells and eosinophils were absent from the testicular parenchyma of several species (rat, dog, cat, bull and deer), although they were present, in most cases, around blood vessels in the tunica albuginea. The presence of high numbers of mast cells and/or eosinophil leukocytes in the testicular parenchyma of some species suggest a role for these cells in local regulatory pathways.

Repair of nonsevere rheumatic aortic valve disease during other valvular procedures: is it safe?

OBJECTIVE

To investigate the long-term performance of aortic valve repair, we analyzed the results obtained in a 22-year period in patients who underwent repair of nonsevere rheumatic aortic valve disease during other valvular procedures.

METHODS

Fifty-three patients (mean 40 +/- 11.6 years of age) with predominant rheumatic mitral valve disease had concomitant aortic valve disease in association with serious tricuspid valve disease in 25 of them. Preoperatively, aortic valve disease was considered moderate in 47.2% of the patients and mild in 52.8%. All patients underwent reparative techniques of the aortic valve (free edge unrolling, 44; subcommissural annuloplasty, 40; commissurotomy, 36) at the time of mitral or mitrotricuspid valve surgery. The completeness of follow-up during the closing interval was 100%, with a mean follow-up of 18.8 years (range 8 to 22.5 years).

RESULTS

Hospital mortality rate was 7.5%. Of 49 surviving patients, 26 (53.1%) died during late follow-up. The actuarial survival curve including hospital mortality was 35.4% +/- 8.7% at 22 years. For patients who underwent mitral and aortic valve surgery, the actuarial survival curve at 22 years was 32.3% +/- 13%, whereas for patients who had a triple-valve operation the survival was 37.0% +/- 10.1% (p = 0.07). Twenty-five patients underwent an aortic prosthetic valve replacement. Actuarial free from aortic structural deterioration and valve-related complications at 22 years was 25.3% +/- 9.3% and 12.7% +/- 4.8%, respectively.

CONCLUSIONS

Long-term functional results of reparative procedures of nonsevere aortic valve disease in patients with predominant rheumatic mitral valve disease have been inadequate at 22 years of follow-up. According to these data, conservative operations for rheumatic aortic valve disease do not seem appropriate.

Bcl-2 slows in vitro breast cancer growth despite its antiapoptotic effect

BACKGROUND

Although the Bcl-2 protein promotes tumor cell survival by blocking programmed cell death (apoptosis), Bcl-2 expression has been associated with favorable prognostic indicators in breast cancer. We hypothesize that despite its antiapoptotic effects, Bcl-2 slows tumor cell proliferation.

MATERIALS AND METHODS

Bcl-2-negative breast cancer cells (SKBr3) were transfected with the bcl-2 gene (Bcl2-1 clone, low expression; Bcl2-2 clone, high expression) or plasmid control (Neo). Cell cycle distribution and kinetics were analyzed using bivariate flow cytometry (PI staining and pulse BrdU uptake). Cells were treated for 72 h with doxorubicin (100 ng/ml) or vehicle (0.01% DMSO) and assayed for cytosolic DNA with diphenylamine to measure apoptosis.

RESULTS

Cell counting showed increased doubling time in the Bcl-2-expressing clones Bcl2-1 and Bcl2-2 (Bcl-2(+)) relative to the Bcl-2-nonexpressing lines SKBr3 and Neo (Bcl-2(-)). Cell cycle analysis showed a decreased S phase fraction in Bcl-2(+) cells. Pulse BrdU uptake showed an increased G1/G0 fraction in Bcl-2(+) cells. Doxorubicin-induced apoptosis occurred in Bcl-2(-) but not in Bcl-2(+) cell lines.

CONCLUSIONS

Despite antiapoptotic effects favoring tumor survival, Bcl-2 prolongs cell cycle. Decreased tumor proliferation may account for the association of Bcl-2 expression with a favorable outcome in breast cancer, even though Bcl-2 may mediate chemoresistance in some patients.

Embryology of esophageal atresia in the adriamycin rat model

PURPOSE

The aim of this study was to describe the dysmorphogenetic process leading to esophageal atresia and tracheoesophageal fistula (EA + TEF) in the recently developed Adriamycin model of the malformation.

METHODS

Time-mated pregnant rats were given either Adriamycin (1.75 mg/kg intraperitoneally) or saline on days 6 to 9 of gestation, and their embryos recovered on days 12, 12.5, and 13 were serially sectioned in the transversal plane and studied microscopically after H&E and PAS staining. The findings were compared with those of age-matched untreated embryos.

RESULTS

All untreated and saline embryos were normal, whereas 49% of Adriamycin embryos had foregut malformations. Tracheoesophageal separation was complete on day 12 in control embryos, whereas 9 of 10 Adriamycin-exposed embryos had a common esophagotrachea with low emergence of the bronchi at that stage. This pattern had evolved into that of a regular EA + TEF in all nine malformed embryos by day 13. On day 12.5, esophagotrachea was found in 6 of 13 and EA + TEF in 5 of 13 embryos. Two had less well-defined malformations.

CONCLUSIONS

Esophagotrachea equivalent to complete tracheoesophageal cleft is the first step leading to EA + TEF in this model. The full-blown malformation is finally acquired by partial loss of the posterior wall of the foregut, which tapers-off in the mediastinal mesenchyme and respiratory differentiation of the anterior wall down to the level of bronchial bifurcation, where it constitutes the fistula and the distal esophagus.

The RNA- and DNA-binding protein TB-RBP is spatially and developmentally regulated during spermatogenesis

Testis brain RNA-binding protein (TB-RBP) suppresses translation in vitro and attaches mRNAs to microtubules by binding to conserved elements in the 3' untranslated regions (UTRs) of specific testis and brain mRNAs. Purification of TB-RBP from testicular and brain cytoplasmic extracts has revealed that mouse TB-RBP is 99% identical to the human protein translin, a recombination "hot spot" binding protein associated with chromosomal translocations. Using a cDNA encoding TB-RBP, the gene copy number and the developmental expression of TB-RBP have been analyzed by Southern blotting, Northern blotting, and in situ hybridization. In the mouse, TB-RBP is encoded by a single copy gene. In mouse testes, three TB-RBP mRNAs of about 1.2, 1.7, and 3.0 kb are developmentally regulated with high levels of expression in meiotic and postmeiotic germ cells. A fourth TB-RBP transcript of about 3.2 kb is seen in the brain. In situ hybridization confirms high levels of testicular TB-RBP mRNAs in meiotic and postmeiotic cells, with the highest levels of TB-RBP mRNAs in pachytene spermatocytes and round spermatids of the mouse and in round spermatids of the rat. RNase H digestion assays reveal that the three TB-RBP mRNAs of mouse testes result from processing differences in their 3' untranslated regions. These data demonstrate that multiple TB-RBP mRNAs are primarily expressed in meiotic and postmeiotic germ cells in the mammalian testis, and although the specific RNA-binding ability of TB-RBP appears limited to brain and testis, TB-RBP mRNAs are widely expressed.

Variability of peak expiratory flow rate in allergic rhinitis and mild asthma: relationship to maximal airway narrowing

BACKGROUND

Previous studies have demonstrated a significant correlation between airway sensitivity to pharmacologic agents and daily peak expiratory flow rate (PEF) variation in asthmatic and nonasthmatic subjects.

OBJECTIVE

The aim of this study was to investigate, both in patients with asthma and in subjects with allergic rhinitis, differences in daily PEF variation between subjects with plateau on the concentration-response curves to methacholine and those without plateau.

METHODS

A total of 120 adults (50 with mild asthma, 52 with allergic rhinitis, and 18 healthy control subjects) were challenged with methacholine (up to 200 mg/mL) and, for the next 14 days, measured their PEF three times daily. The response to methacholine was measured by the percent decrease in FEV1. A maximal response plateau was considered if three or more of the highest concentrations fell within a 5% response range. Diurnal PEF variation was expressed as the amplitude percent mean.

RESULTS

A plateau response was detected in 11 (22%) asthmatic patients, in 33 (63%) subjects with allergic rhinitis, and in 17 (94%) healthy subjects. Diurnal PEF variation was significantly greater (P < .01) in the asthmatic group without a plateau (8.8 +/- 3.7%) compared with the three groups with a plateau (asthma = 5.5 +/- 2.9%; allergic rhinitis = 4.6 +/- 2.1%; healthy = 4.7 +/- 2.3%). Those three groups with a plateau were not significantly different from each other with respect to PEF variability. Diurnal PEF variation was significantly higher in allergic rhinitis patients without plateau (7.6 +/- 3.5%) than in allergic rhinitis patients with plateau (P < .01) and healthy subjects (P < .05). The rhinitic group without a plateau, however, was not significantly different from either the asthmatic group without plateau or the asthmatic group with plateau.

CONCLUSIONS

We conclude that in both asthmatic patients and subjects with allergic rhinitis, the shape of the concentration-response curve to methacholine provides new information on the relationship between airway responsiveness and PEF variability. Further, allergic rhinitis subjects without evidence of plateau have a degree of diurnal PEF variation similar to that found in patients with mild asthma. This could indicate that those subjects may have subclinical inflammatory changes in the airways.