Bombesin Receptor Gene Expression in Rat Embryos: Transient GRP-R Gene Expression in the Posterior Pituitary

Bombesin-like peptides can stimulate growth of cultured cells derived from ectoderm, endoderm, or mesenchyme and act as autocrine growth factors in some lung carcinoma cell lines. Recently, cDNA clones for two mammalian bombesin receptors (BN-R), gastrin-releasing peptide receptor (GRP-R) and neuromedin B receptor (NMB-R), were characterized and shown to be present in distinct regions of the central nervous system at birth. To determine whether the spatial and/or temporal expression of BN-R genes correlated with tissue-specific or organ-specific developmental events, the prenatal distribution of GRP-R and NMB-R mRNAs were compared by in situ hybridization histochemistry. The differential expression of these two BN-R genes was striking. From early embryonic stages, GRP-R mRNA was expressed in various organs, including nervous, urogenital, respiratory, and digestive systems. In contrast, NMB-R gene expression was detected at later embryonic stages and the distribution of expression was much more limited. In most tissues, after onset of expression, both receptor mRNAs showed a steady increase in expression throughout development. However, transient expression of GRP-R mRNA was seen in the posterior pituitary. Intense GRP-R labeling of posterior pituitary cells was seen from E12 to E20, but at birth, GRP-R mRNA levels were undetectable. These results suggest that (a) two BN-R subtypes mediate independent functions during development, (b) ontogenesis of multiple organs may involve GRP-R mediated events, and (c) GRP-R gene expression is involved in differentiation/development of the pituitary gland.

Inversion of spin photocurrent due to resonant transmission

We report on the inversion of spin-dependent photocurrent via interface localized states formed at the interface of an Fe/n-AlGaAs/GaAs quantum well heterostructure by means of an optical spin orientation technique. A careful adjustment of the excitation photon energy, which is determined by a separate analysis of electroluminescence spectra under a spin injection condition, enables us to explore the spin-dependent characteristics of photoelectron transmission from the quantum well into Fe. The bias dependence of the spin-dependent photocurrent shows clear spikelike features at the voltage which is compatible with the formation of the interface localized resonant states in the Schottky depletion layer.

Laminoplasty for patients aged 75 years or older with cervical myelopathy

PURPOSE

To assess the neurological and walking status of 56 elderly patients after cervical myelopathy to determine whether the surgery was justified.

METHODS

Records of 23 men and 33 women aged 75 to 86 (mean, 79) years who underwent laminoplasty for cervical myelopathy were retrospectively reviewed. They had been followed up for a mean of 3.5 (range, 0.2-8.6) years. Walking status was assessed according to long-term care insurance criteria. In 45 patients with more than 2 years of follow-up, neurological status was evaluated according to the Japanese Orthopaedic Association (JOA) score. Neurological recovery rate was classified as excellent, good, fair, poor, and worse.

RESULTS

Postoperatively, of the 47 patients still living, 22 could walk independently, 22 required assistance outdoors, 2 were using a wheelchair, and one was bedridden. The mean JOA score was 9.7 preoperatively, 12.2 one year postoperatively, and 11.8 at final assessment (p<0.001). The mean neurological recovery rate was 29% at one-year follow-up and 24% at final assessment (p=0.06).

CONCLUSION

Although excellent results were not expected in elderly patients, surgery to maintain independent walking status was justified in most of our patients.

Combined injuries of the brachial plexus and spinal cord

A total of 11 patients with combined traumatic injuries of the brachial plexus and spinal cord were reviewed retrospectively. Brachial plexus paralysis in such dual injuries tends to be diagnosed and treated late and the prognosis is usually poor. The associated injuries, which were all on the same side as the plexus lesion, were to the head (nine cases), shoulder girdle (five), thorax (nine) and upper limb (seven). These other injuries were responsible for the delayed diagnosis of brachial plexus paralysis and the poor prognosis was probably because of the delay in starting treatment and the severity of the associated injuries. When such injuries are detected in patients with spinal cord trauma, it is important to consider the possibility of involvement of the brachial plexus.

Disruption of neuromedin B receptor gene results in dysregulation of the pituitary-thyroid axis

The level of thyrotropin (TSH) secretion is determined by the balance of TSH-releasing hormone (TRH) and thyroid hormones. However, neuromedin B (NB), a bombesin-like peptide, highly concentrated in the pituitary, has been postulated to be a tonic inhibitor of TSH secretion. We studied the pituitary-thyroid axis in adult male mice lacking NB receptor (NBR-KO) and their wild-type (WT) littermates. At basal state, NBR-KO mice presented serum TSH slightly higher than WT (18%, P< 0.05), normal intra-pituitary TSH content, and no significant changes in alpha and beta TSH mRNA levels. Serum thyroxine was normal but serum triiodothyronine (T3) was reduced by 24% (P< 0.01) in NBR-KO mice. Pituitaries of NBR-KO mice exhibited no alteration in prolactin mRNA expression but type I and II deiodinase mRNA levels were reduced by 53 and 42% respectively (P< 0.05), while TRH receptor mRNA levels were importantly increased (78%, P< 0.05). The TSH-releasing effect of TRH was significantly higher in NBR-KO than in WT mice (7.1-and 4.0-fold respectively), but, while WT mice presented a 27% increase in serum T3 (P< 0.05) after TRH, NBR-KO mice showed no change in serum T3 after TRH. NBR-KO mice did not respond to exogenous NB, while WT showed a 30% reduction in serum TSH. No compensatory changes in mRNA expression of NB or other bombesin-related peptides and receptors (gastrin-releasing peptide (GRP), GRP-receptor and bombesin receptor subtype-3) were found in the pituitary of NBR-KO mice. Therefore, the data suggest that NB receptor pathways are importantly involved in thyrotroph gene regulation and function, leading to a state where TSH release is facilitated especially in response to TRH, but probably with a less-bioactive TSH. Therefore, the study highlights the important role of NB as a physiological regulator of pituitary-thyroid axis function and gene expression.

Amla (Emblica officinalis Gaertn.) Extracts Reduce Oxidative Stress in Streptozotocin-Induced Diabetic Rats

The antioxidant properties of amla extracts and their effects on the oxidative stress in streptozotocin-induced diabetes were examined in rats. Amla in the form of either the commercial enzymatic extract SunAmla (Taiyo Kagaku Co. Ltd., Yokkaichi, Japan) (20 or 40 mg/kg of body weight/day) or a polyphenol-rich fraction of ethyl acetate extract (10 or 20 mg/kg of body weight/day) was given orally for 20 days to the streptozotocin-induced diabetic rats. Amla extracts showed strong free radical scavenging activity. Amla also showed strong inhibition of the production of advanced glycosylated end products. The oral administration of amla extracts to the diabetic rats slightly improved body weight gain and also significantly alleviated various oxidative stress indices of the serum of the diabetic rats. The elevated serum levels of 5-hydroxymethylfurfural, which is a glycosylated protein that is an indicator of oxidative stress, were significantly reduced dose-dependently in the diabetic rats fed amla. Similarly, the serum level of creatinine, yet another oxidative stress parameter, was also reduced. Furthermore, thiobarbituric acid-reactive substances levels were significantly reduced with amla, indicating a reduction in lipid peroxidation. In addition, the decreased albumin levels in the diabetic rats were significantly improved with amla. Amla also significantly improved the serum adiponectin levels. These results form the scientific basis supporting the efficacy of amla for relieving the oxidative stress and improving glucose metabolism in diabetes.

Role of bombesin (BN)-like peptides/receptors in emotional behavior by comparison of three strains of BN-like peptide receptor knockout mice

Bombesin (BN)-like peptides are involved in the regulation of a wide variety of behaviors, such as spontaneous activity and feeding. We assessed the role of BN-like peptides/receptors in emotional and/or anxiety-related behavior using three strains of knockout mice, each deficient in a single BN-like peptide receptor (gastrin-releasing peptide receptor, bombesin receptor subtype-3, or neuromedin B receptor). Two representative behavioral paradigms, the light-dark (L-D) box test and the elevated plus maze test, were chosen for this purpose. In these two tests, the level of anxiety can be measured as the preference for exploring the light box, or the length of time spent in the open arms, respectively. By conventional parameters, the only significant finding was that BRS-3-deficient mice exhibited a longer duration of remaining in the open arms compared to the wild-type cohort (P < 0.01). However, analyses of risk assessment behavior revealed that BRS-3-deficient mice exhibited increased 'stretched attend posture' behavior (P < 0.01, compared to wild-type mice in both the L-D box and elevated plus maze tests) while NMB-R-deficient mice exhibited decreased behavior (P < 0.05, compared to wild-type mice in both tests). These results suggest that BN-like peptides/receptors may play a role in modulating emotion including some forms of anxiety (e.g., risk assessment behavior). Further, we found that the type of emotional behavior to which each of the peptide/receptor pathways contributes can be clearly specified.

Intramedullary teratoma of the spine: report of two adult cases

STUDY DESIGN

Two case reports of intramedullary teratoma in the spinal cord of adults, and a review of the literature.

OBJECTIVE

To investigate and describe unusual cases of spinal teratoma using MRI to define features that may be used to avoid misdiagnosis.

SETTING

A department of orthopedic surgery in Japan.

METHODS

One patient, a 37-year-old woman, was referred because of gait disturbance. She was evaluated by myelography, CT scan with myelography, and MRI. T12 through L1 laminoplasty was performed and the tumor was subtotally removed. The other patient, a 56-year-old man, was referred because of muscle weakness and sensory disturbance. MRI revealed multiple spinal tumors. C4 through C6 laminoplasty and T12 through L2 laminoplasty were performed, and the tumors in these regions were subtotally removed.

RESULTS

In Case 1, the postoperative course was excellent, and histological examination of the resected specimen revealed a spinal teratoma consisting of ectodermal and mesodermal elements. In Case 2, the symptoms were resolved after surgery, and ectodermal, mesodermal and endodermal elements were revealed.

CONCLUSIONS

Although intramedullary teratomas are very rare in adults, they need to be considered in differential diagnosis.

Ossification of the ligamentum flavum associated with osteoblastoma: a report of three cases

We report three cases of spinal osteoblastoma with ossification of the ligamentum flavum (OLF) adjacent to the tumor. The patients in this report, all young adults, had no symptoms except for back pain. Computed tomography (CT) demonstrated a typical radiolucent nidus in the spinal pedicle/lamina with a dense sclerotic rim. In addition, ectopic bone formation at the insertion point of the ligamentum flavum adjacent to the tumor was clearly illustrated. Magnetic resonance imaging (MRI) revealed the tumor and surrounding inflammatory responses, but OLF was not detected clearly. Histological examination revealed endochondral ossification of the ligamentum flavum that is quite unusual for normal young adults. Immunohistochemical assays in one case demonstrated that bone morphogenetic protein (BMP)-2/4 was expressed in the osteoblastic tumor cells. This case raises the possibility that BMPs secreted from the tumor cells triggered ectopic ossification in the spinal ligament.

Subtotal corpectomy versus laminoplasty for multilevel cervical spondylotic myelopathy: a long-term follow-up study over 10 years

STUDY DESIGN

A retrospective study was conducted.

OBJECTIVE

To compare the long-term outcomes of subtotal corpectomy and laminoplasty for multilevel cervical spondylotic myelopathy.

SUMMARY OF BACKGROUND DATA

No study has compared the long-term outcomes between subtotal corpectomy and laminoplasty for multilevel cervical spondylotic myelopathy.

METHODS

In this study, 23 patients treated with subtotal corpectomy and 24 patients treated with laminoplasty were followed up for 10 to 14 years after surgery. Neurologic recovery, late deterioration, axial pain, radiographic results (degenerative changes at adjacent levels, alignment, and range of motion of the cervical spine), and surgical complications were compared between the two groups.

RESULTS

No significant difference in neurologic recovery was found between the two groups 1 and 5 years after surgery, or at the latest follow-up assessment. Neurologic status deteriorated in one patient of the subtotal corpectomy group because of adjacent degeneration, and in one patient of the laminoplasty group because of hyperextension injury. Axial pain was observed in 15% of the corpectomy group and in 40% of the laminoplasty group (P < 0.05). In the corpectomy group, listhesis exceeding 2 mm developed at 38% of the upper adjacent levels, and osteophyte formation at 54% of the lower adjacent levels. In the laminoplasty group, kyphotic deformity developed in one patient (6%) after surgery. In the corpectomy group, the mean vertebral range of motion had decreased from 39.4 degrees to 19.2 degrees (49%) by the final follow-up assessment. In the laminoplasty group, the mean vertebral range of motion had decreased from 40.2 degrees to 11.6 degrees (29%) by the final follow-up assessment. Neurologic complications related to the surgery occurred in two patients (one myelopathy from bone graft dislodgement and one C5 root palsy from bone graft fracture) of the corpectomy group and four patients (C5 root palsy) of the laminoplasty group. All of these patients recovered over time. The corpectomy group needed longer operative time (P < 0.001) and tended to have more blood loss (P = 0.24). Six patients in the corpectomy group needed posterior interspinous wiring because of pseudarthrosis.

CONCLUSIONS

Subtotal corpectomy and laminoplasty showed an identical effect from a surgical treatment for multilevel cervical spondylotic myelopathy. These neurologic recoveries usually last more than 10 years. In the subtotal corpectomy group, the disadvantages were longer surgical time, more blood loss, and pseudarthrosis. In the laminoplasty group, axial pain occurred frequently, and the range of motion was reduced severely.

Predictability of internal carotid artery (ICA) dissectability in cases showing ICA involvement in parasellar meningioma

The present study identified predictors for surgical internal carotid artery (ICA) dissection in cases showing ICA involvement in parasellar meningiomas. Twelve cases encountered over the past 4 years were reviewed. Based on MRI findings, patients were divided into two groups; six patients demonstrated complete ICA involvement (encasement) and the other six showed partial ICA involvement (engulfment). The ICA was dissected in all cases in the engulfment group and in four of six cases in the encasement group. The ICA can be dissected even if it is involved at the centre of the tumour if the tumour is soft and can be aspirated. Preservation of the perforating arteries is more important and more difficult. Angiographic finding showing encasement of a long segment of the ICA is unfavourable because of the high possibility that the perforating arteries are involved. Local stenosis of ICA is another unfavourable finding for surgical dissection because tumour invasion of the arterial wall would be suspected. Thus, ICA encasement by the tumour is the less favourable finding for surgery but it is not a decisive predictor. More important findings for ICA dissection in cases showing ICA encasement are involvement of a long segment of the ICA and local ICA stenosis on angiogram.

[Ecophysiological features of mat-forming bacteria Thioploca in bottom sediments of Frolikha Bay, northern Baikal]

A colorless sulfur bacterium of the genus Thioploca, which forms bacterial mats, was studied in the region of underwater thermal vents (Frolikha Bay, northern Baikal). The organism occurs under microaerobic conditions in top sediment layers, and its biomass can amount to 65 mg of wet weight per 1 kg of silt. Individual filaments of the bacterium penetrate the anaerobic zone to the depth of 19 cm. Thioploca is distributed in a mosaic pattern over the bottom of the bay. Thioploca mats are typically found near vents that discharge low-temperature underground water. In the form of separate filaments, this bacterium is more widely distributed in the top sediment layer, particularly in sediments with a more active sulfate reduction. The bacteria from the deep-water and coastal areas of the bay have different morphology. Cells of Thioploca are able to accumulate nitrate, and the coefficient of nitrate accumulation in wet bacterial mass in relation to the near-bottom water is 1.3 x 10(4), suggesting a similarity of metabolism with seawater species. A more lightweight isotopic composition of nitrogen in cell mass as compared to that of representatives of zoobenthos also indicates an active metabolism of nitrogen, apparently, in the process of nitrogen respiration. Comparison of the composition of stable isotopes of carbon in the biomass of representatives of different trophic levels, including Thioploca, found at a depth of 105 m indicates its planktonic origin, whereas, in the deeper bay region, the biomass of Thioploca incorporates more of the light carbon originating from biogenic methane.

Proadrenomedullin N-terminal 20 peptide (PAMP) inhibits food intake and gastric emptying in mice

We found that proadrenomedullin N-terminal 20 peptide (PAMP) decreased dose-dependently (3-30 nmol/mouse) food intake after intra-third cerebroventricular administration in fasted ddY mice. Gastric emptying also was delayed after central injection of PAMP. In our previous study, PAMP was demonstrated to elicit hyperglycemia via bombesin (BN) receptor. Then, we examined whether the effects of PAMP on feeding and gastric emptying were induced through BN receptor. Surprisingly, PAMP-induced reductions in feeding and gastric emptying rate were not blocked by a BN antagonist, [D-Phe(6), Leu-NHEt(13), des-Met(14)]-BN (6-14). PAMP suppressed feeding in mice lacking gastrin-releasing peptide receptor or BN receptor subtype-3. These results indicate that centrally administered PAMP inhibits food intake, involving the delayed gastric emptying, not through BN receptors but through selective PAMP receptor.

Female gastrin-releasing peptide receptor (GRP-R)-deficient mice exhibit altered social preference for male conspecifics: implications for GRP/GRP-R modulation of GABAergic function

We studied female GRP-R-deficient mice with respect to olfactory function and social behavior toward male conspecifics. Results of a food exploration test (hidden cookie method) revealed that the olfactory ability of these mutant mice is identical to that of wild-type mice. However, when preference toward either a socially dominant or subordinate male mouse was assessed in a social preference test, wild-type mice showed a greater preference for socially dominant males than did GRP-R-deficient mice. In contrast, in a social investigation test to an anesthetized male mouse, GRP-R-deficient mice exhibited greater investigatory behavior toward the target male than did wild-type mice. When female C57BL/6J mice were given diazepam (0, 1, 2 or 4 mg/kg, i.p.), their investigatory behavior to the anesthetized male target was increased in a dose-dependent manner. Conversely, i.p. administration of bicuculline (1 mg/kg) significantly decreased the social investigatory behavior of female GRP-R-deficient mice, but not of wild-type mice. These results indicate that female GRP-R-deficient mice exhibit altered responsiveness to male conspecifics relative to their wild-type counterparts, and suggest that this outcome may be attributable, at least in part, to altered GABAergic function in these mutant mice.

The global methane cycle: isotopes and mixing ratios, sources and sinks

A review of the global cycle of methane is presented with emphasis on its isotopic composition. The history of methane mixing ratios, reconstructed from measurements of air trapped in ice-cores is described. The methane record now extends back to 420 kyr ago in the case of the Vostok ice cores from Antarctica. The trends in mixing ratios and in delta13C values are reported for the two Hemispheres. The increase of the atmospheric methane concentration over the past 200 years, and by 1% per year since 1978, reaching 1.7 ppmv in 1990 is underlined. The various methane sources are presented. Indeed the authors describe the methane emissions by bacterial activity under anaerobic conditions in wet environments (wetlands, bogs, tundra, rice paddies), in ruminant stomachs and termite guts, and that originating from fossil carbon sources, such as biomass burning, coal mining, industrial losses, automobile exhaust, sea floor vent, and volcanic emissions. Furthermore, the main sinks of methane in the troposphere, soils or waters via oxidation are also reported, and the corresponding kinetic isotope effects.

Bombesin-like peptides: studies on food intake and social behaviour with receptor knock-out mice

Bombesin (BN)-like peptides and receptors for these peptides are widely distributed in mammalian peripheral tissues and the central nervous system. The physiological and behavioural functions of these peptides have been clarified by both in vivo and in vitro studies. In spite of intensive investigations, the functions of endogenous BN-like peptides remain unclear. In order to specify these functions, our group and another laboratory generated by gene targeting mutant mice that lack one of the three BN-like peptide receptors found in mammals, ie neuromedin B receptor (NMB-R; BB1), gastrin-releasing peptide receptor (GRP-R; BB2), or bombesin receptor subtype-3 (BRS-3; BB3). Using these mutant mouse, we have found unexpected phenotypes, such as hyperphagia and obesity in the BRS-3-deficient mouse, and abnormal social behaviour in the GRP-R-deficient mouse. In the present study, we present our most recent findings in addition to previous studies and discuss the functions of BN-like peptides related to feeding and social behaviour from the point of view of knock-out mice studies.

Reduced GLP-1 and insulin responses and glucose intolerance after gastric glucose in GRP receptor-deleted mice

By applying a newly developed ELISA technique for determining biologically active intact glucagon-like peptide [GLP-1, GLP-1-(7-36)amide] in mouse, plasma baseline GLP-1 in normal NMRI mice was found to be normally distributed (4.5 +/- 0.3 pmol/l; n = 72). In anesthetized mice, gastric glucose (50 or 150 mg) increased plasma GLP-1 levels two- to threefold (P < 0.01). The simultaneous increase in plasma insulin correlated to the 10-min GLP-1 levels (r = 0.36, P < 0.001; n = 12). C57BL/6J mice deleted of the gastrin-releasing peptide (GRP) receptor by genetic targeting had impaired glucose tolerance (P = 0.030) and reduced early (10 min) insulin response (P = 0.044) to gastric glucose compared with wild-type controls. Also, the GLP-1 response to gastric glucose was significantly lower in the GRP receptor-deleted mice than in the controls (P = 0.045). In conclusion, this study has shown that 1) plasma levels of intact GLP-1 increase dose dependently on gastric glucose challenge in correlation with increased insulin levels in mice, and 2) intact GRP receptors are required for normal GLP-1 and insulin responses and glucose tolerance after gastric glucose in mice.

Idiopathic spinal cord herniation: report of three cases and review of the literature

STUDY DESIGN

Three case reports and a literature review are presented.

OBJECTIVE

To describe characteristic clinical and radiographic findings of idiopathic spinal cord herniation.

SUMMARY OF BACKGROUND DATA

Idiopathic spinal cord herniation is a rare disease, with only 26 cases reported before the current study.

METHODS

Three cases of idiopathic spinal cord herniation are reported, and previous reports on this subject are reviewed.

RESULTS

The responsible regions were in the thoracic spine from T2 to T7. Symptoms were mainly unilateral muscle atrophy in the lower extremity and sensory disturbance below the thoracic level. These symptoms had been progressing gradually. Magnetic resonance imaging demonstrated a unique feature: The spinal cord shifted anteriorly in a few segments. Computed tomographic myelogram showed another distinctive picture: There was no subarachnoid space anterior to the spinal cord.

CONCLUSIONS

Because idiopathic spinal cord herniation is out of the concept of "compression myelopathy," this condition may be a pitfall in the diagnosis. Idiopathic spinal cord herniation should be recognized as one of the treatable causes for thoracic myelopathy.

Male mice lacking the gastrin-releasing peptide receptor (GRP-R) display elevated preference for conspecific odors and increased social investigatory behaviors

Previously, we generated gastrin-releasing peptide receptor null mutant mice (GRP-R-deficient mice), and found that these animals displayed increased non-aggressive social responses in an ordinary social interaction test using a resident-intruder method. In the present study, we examined in more detail the social behaviors of GRP-R-deficient male mice. In social interaction tests, GRP-R-deficient mice showed more social responses, such as sniffing and nosing, relative to wild-type mice, and similar results were obtained whether GRP-R-deficient mice served as intruders or residents. In the same way, they showed more contact behaviors toward an anesthetized conspecific, and less locomotor activity than wild-type mice in a social investigation test toward an anesthetized male mouse. Since olfactory systems play important roles in the social behavior of rodents, olfactory preference tests were conducted in order to evaluate the olfactory properties of GRP-R-deficient mice. The results suggest that no differences exist between wild-type mice and GRP-R-deficient mice in the preference between a novel sawdust odor and their own odor, or that of other male mice. However, GRP-R-deficient mice preferred the odor of other male mice to their own, in contrast to wild-type mice. Furthermore, the preferences of GRP-R-deficient and wild-type mice were not disrupted by intraperitoneal infusion of diazepam (1.5 mg/kg). These results indicate that neither the motion, nor the behavior of conspecifics, nor reduced anxiety lead to the increased non-aggressive social responses and/or social investigatory behaviors in GRP-R-deficient mice. Rather, these latter behaviors may be a consequence of altered cognition of conspecific odors in the mutant mice.

IgE-binding activity to enzyme-digested ovomucoid distinguishes between patients with contact urticaria to egg with and without overt symptoms on ingestion

BACKGROUND

We occasionally see egg-allergic children who develop contact urticaria to hen's egg despite the absence of the overt symptoms on ingestion. The mechanisms remain to be elucidated.

METHODS

Twenty-one subjects with positive reactions to 20-min patch tests for egg-white antigens were divided into subgroups with positive (n = 10) and negative (n = 11) results to oral challenge tests by the same antigens. We measured IgE antibody for egg white and its components, and IgE-binding activities to digestive enzyme-treated ovomucoid by RAST inhibition.

RESULTS

There were no significant differences in IgE antibody titers to egg white (positive vs negative: 30.3% vs 15.3%, P=0.130), ovomucoid (21.5% vs 10.2%, P= 0.078), ovotransferrin (9.9% vs 3.7%, P = 0.105), and lysozyme (3.4% vs 2.9%, P=0.944), except ovalbumin (16.8% vs 5.6%, P=0.024), between the positive and negative subjects in the provocation tests. In contrast, the concentration (1.93 microg/ml) of pepsin-treated ovomucoid needed for 50% RAST inhibition in the challenge-positive subjects was significantly (P=0.0003) lower than that (114.9 microg/ml) of negative subjects. Similar but less significant differences were obtained when ovomucoid fragments treated with chymotrypsin (0.91 microg/ml vs 6.86 microg/ml, P=0.014) and trypsin (0.75 microg/ml vs 4.67 microg/ml, P= 0.041) were used as inhibitors.

CONCLUSIONS

We suggest that IgE antibodies from subjects showing contact urticaria despite the absence of reactions to the ingestion of egg white recognize the epitope(s) unstable to digestive enzymes.

Perfusion-limited recovery of evoked potential function after spinal cord injury

STUDY DESIGN

The current study was designed to determine whether progressive spinal cord damage during residual compression is caused by low blood flow and ischemia.

OBJECTIVES

The purpose of this experiment was to determine the effects of sustained spinal cord compression on regional blood flow and evoked potential recovery after time-dependent decompression.

SUMMARY OF BACKGROUND DATA

Spinal cord injury after trauma is commonly associated with residual cord compression. Although decreased blood flow has been reported after spinal cord contusion, the effect of residual spinal cord displacement on reperfusion of blood flow or recovery of neurologic function remains unclear.

METHODS

Eighteen beagles were anesthetized, and the spinal cord at T13 was loaded dorsally under precision loading conditions until evoked potential amplitudes were reduced by 50%. At this function endpoint, spinal cord displacement was maintained for 90 minutes. Somatosensory-evoked potentials were measured at regular intervals until 3 hours after decompression. Regional spinal cord blood flow was measured with a fluorescent microsphere technique at regular time points during and after spinal cord decompression.

RESULTS

Within 5 minutes after dynamic cord compression was discontinued, evoked potential signals were absent in all dogs. Evoked potential recovery was observed after decompression in 7 of 18 dogs. Regional spinal cord blood flow at baseline, 21.8 +/- 1.9 mL/100 g. min (mean +/- SE), decreased to 3.9 +/- 0.9 mL/100 g. min after dynamic compression was discontinued. Although spinal cord-piston interface pressure dissipated by 87% of maximum interface pressure during sustained compression, mean blood flow recovered to only 34% of baseline flow. In the 7 dogs that recovered evoked potential function, blood flow increased to 11.3 +/- 2.7 mL/100g. min immediately before decompression (P < or = 0.05). In the 11 dogs that did not recover evoked potential function after decompression, regional blood flow did not improve during sustained compression.

CONCLUSIONS

Recovery of evoked potential function after decompression corresponded with a greater return of blood flow during sustained displacement and greater reperfusion of blood flow associated with decompression.

Proadrenomedullin N-terminal 20 peptide (PAMP) elevates blood glucose levels via bombesin receptor in mice

We found a potent hyperglycemic effect of proadrenomedullin N-terminal 20 peptide (PAMP) after intra-third cerebroventricular administration at a dose of 10 nmol in fasted mice. PAMP has four homologous residues with bombesin (BN), a hyperglycemic peptide. PAMP showed affinity for gastrin-releasing peptide preferring receptor (GRP-R) and neuromedin B preferring receptor. The PAMP-induced hyperglycemic effect was inhibited by [D-Phe(6), Leu-NHEt(13), des-Met(14)]-BN (6-14), GRP-R specific antagonist, indicating that the hyperglycemic effect is mediated at least in part via GRP-R. Furthermore, pretreatment of alpha-adrenergic blocker inhibited the PAMP-induced hyperglycemia and hyperglucagonemia, suggesting that the increase of glucagon secretion through alpha-adrenergic activation is involved in this hyperglycemic effect of PAMP.

Intramolecular stable isotope ratios of N2O in the tropical swamp forest in Thailand

The dry-wet cycle is a common climatic phenomenon in the tropical regions of monsoon-affected Asia. An intermittent increase in N2O was clearly observed in the Bang Nara River, with a tropical swamp catchment at the beginning of rainy season of November 1997. The intramolecular distribution of isotopes clearly demonstrated that nitrification is the major process for the production of N2O. Using stable isotope data, the production mechanism of N2O in the study areas was found to vary in time and space with changes in the redox boundary along the water flow.

Influence of anteroposterior and mediolateral instability on range of motion after total knee arthroplasty: an ultrasonographic study

Ultrasonographically, the femoral component and the tibial plate of total knee prostheses are strongly echogenic, while the high-density polyethylene insert is hypoechoic. This study evaluated the influence of mediolateral and anteroposterior stability after total knee arthroplasty (TKA) on range of motion using real-time monitoring with ultrasound. Mediolateral stress translation, which is increased by horizontal resection of more bone at the ends of the femur or tibia for easy prosthesis implantation, was examined on coronal scans at the level of the collateral ligaments. Anteroposterior drawer was examined on sagittal scans at the level of the patellar tendon. Mediolateral translation (0-10 mm; mean 2.24 mm) did not correlate with range of motion, while anteroposterior drawer (2-10 mm, mean 5.05 mm) correlated well with range of motion. These ultrasonographic findings suggest that horizontal over-resection of the ends of the femur and tibia contributed to joint laxity, which would not result in better ROM. Rollback and sliding of the femoral component on the tibia, which is believed to be correlated with anteroposterior drawer, may be important in achieving better range of motion and obtaining excellent results in TKA.

Clinical significance of IgE-binding activity to enzymatic digests of ovomucoid in the diagnosis and the prediction of the outgrowing of egg white hypersensitivity

BACKGROUND

We frequently encounter subjects without overt symptoms despite high IgE antibodies to egg white and its components. The measurements of these antibodies are not necessarily efficient for the diagnosis or the prediction of the outcome of egg allergy in children.

METHODS

Specific IgE antibodies to egg white and its components, including ovomucoid, ovalbumin, ovotransferrin and lysozyme, were measured by direct RAST assays. IgE-binding activity to ovomucoid degraded by pepsin, trypsin and chymotrypsin was examined by RAST inhibition. Thirty subjects were divided into two groups with positive (n=18; mean age +/- SD = 42 +/-25 months) and negative (n=12; mean age +/- SD = 48 +/-31 months) oral challenge tests with egg white antigens. The individuals with positive results to the first challenge tests were given the second provocation tests at mean intervals of 32 months. IgE-binding activity of the sera collected on the first challenge to these ovomucoid fragments was compared between subjects with positive and negative reactions to the follow-up challenge tests.

RESULTS

There were no significant differences in IgE antibody titers to egg white and its components between the positive and negative groups at the first and the second challenge tests. IgE-binding activity to ovomucoid digests after treatments with pepsin (p = 0.000008) and trypsin (p=0.037), except chymotrypsin (p=0.062), were significantly higher in subjects with positive challenge tests than in those with negative results. The difference was most remarkable in the IgE-binding to pepsin digests; the average concentrations (mean - SD and mean + SD) needed for 50% RAST inhibition in the positive group and in the negative group were 2.6 microg/ml (0.3 and 25) and 94.2 microg/ml (24.7 and 358.7), respectively. A significant difference was still observed in the inhibition tests using filtrates of pepsin digests with a membrane with MW 10,000 (p=0.014) and 3,000 (p=0.042) of cutoff. The concentration (mean= 0.8, mean - SD=0.2, mean + SD=3.4; microg/ml) of pepsin-treated ovomucoid required for 50% RAST inhibition in the subjects with positive second challenge results was significantly (p=0.033) lower than that (mean=6.8, mean-SD=0.6, mean + SD=73.9) of the negative group.

CONCLUSION

IgE-binding activity to pepsin-digested ovomucoid was of diagnostic value to distinguish the challenge-positive subjects from the negative subjects. Subjects with high IgE-binding activity to pepsin-treated ovomucoid are unlikely to outgrow egg white allergy.

Hyperresponsiveness to palatable and aversive taste stimuli in genetically obese (bombesin receptor subtype-3-deficient) mice

Taste preference in obese mice was examined using genetically obese (bombesin receptor subtype-3: BRS-3 deficient) animals. Preference for either sodium saccharin (0.2%). sodium chloride (0.9%), citric acid (0.1%), or quinine sulfate (0.002%) solution was examined using a two-bottle test situation, and BRS-3 deficient mice not only showed a stronger preference for saccharin solution, but also a stronger aversive response to quinine solution, relative to wild-type littermates. Furthermore, a conditioned taste-aversion test measured the consumption of sodium saccharin (0.2%) and sodium chloride (0.9%) solutions after intraperitoneal injection of LiCl (0.3 M, 1 mg/kg), and BRS-3-deficient mice exhibited stronger aversion to both solutions than did control animals. In situ hybridization demonstrated that the BRS-3 gene is expressed in the parabrachial nucleus, the medial and central nuclei of the amygdala, and the hypothalamic nuclei such as paraventricular nucleus, all of which are known to be involved in taste perception. These results suggest that expression of the BRS-3 gene in these nuclei is important for the modulation of taste preference, as well as the development of obesity.

Can intramedullary signal change on magnetic resonance imaging predict surgical outcome in cervical spondylotic myelopathy?

STUDY DESIGN

A retrospective study evaluating magnetic resonance imaging, computed tomographic myelography, and clinical parameters in patients with cervical spondylotic myelopathy.

OBJECTIVES

To investigate whether magnetic resonance imaging can predict the surgical outcome in patients with cervical spondylotic myelopathy.

SUMMARY OF BACKGROUND DATA

No previous studies have established whether areas of high signal intensity in T2-weighted magnetic resonance images can be a predictor of surgical outcomes.

METHODS

Fifty patients with cervical spondylotic myelopathy were examined by magnetic resonance imaging and computed tomographic myelography before surgery and by delayed computed tomographic myelography after surgery. The correlation between the recovery rate and the clinical and imaging parameters was analyzed.

RESULTS

The best prognostic factor was the transverse area of the spinal cord at maximum compression (correlation coefficient, R = 0.58). The presence of high signal intensity areas on T2-weighted magnetic resonance images correlated poorly with the recovery rate (R = -0.29). However, patients with multisegmental areas of high signal intensity on T2-weighted magnetic resonance images tended to have poor surgical results associated with muscle atrophy in the upper extremities. Postoperative delayed computed tomographic myelography showed that multisegmental areas of high signal intensity on T2-weighted magnetic resonance images probably represent cavitation in the central spinal cord.

CONCLUSIONS

Patients with multisegmental areas of high signal intensity on T2-weighted magnetic resonance images tended to have poorer surgical results. However, the transverse area of the spinal cord at the level of maximum compression was a better prognostic indicator.

Effects of abdominal belts on intra-abdominal pressure, intra-muscular pressure in the erector spinae muscles and myoelectrical activities of trunk muscles

OBJECTIVE

To evaluate the effects of abdominal belts on lifting performance, muscle activation, intra-abdominal pressure and intra-muscular pressure of the erector spinae muscles.

DESIGN

Simultaneous measurement of intra-abdominal pressure, intra-muscular pressure of the erector spinae muscles was performed during the Valsalva maneuver and some isometric lift exertions.

BACKGROUND

While several hypotheses have been suggested regarding the biomechanics of belts and performance has been found to increase when lifting with belts, very little is known about the modulating effects on trunk stiffness. At present, there is no reason to believe that spine tolerance to loads increases with belts.

METHODS

An abdominal belt designed for weightlifting was used. Intra-abdominal pressure, intra-muscular pressure of the erector spinae muscles and myoelectric activities of trunk muscles (erector spinae, rectus abdominis and external oblique) were measured simultaneously during the Valsalva maneuver as well as three types of isometric lifting exertions (arm, leg and torso lift). A paired t-test was used to analyze for statistical differences between the two conditions (without-belt and with-belt) in intra-abdominal pressure, intra-muscular pressure of the erector spinae muscles and in the integrated EMG of the trunk muscles.

RESULTS

Intra-muscular pressure of the erector spinae muscles increased significantly by wearing the abdominal belt during Valsalva maneuvers and during maximum isometric lifting exertions, while maximum isometric lifting capacity and peak intra-abdominal pressure were not affected. Integrated EMG of rectus abdominis increased significantly by wearing the abdominal belt during Valsalva maneuvers (after full inspiration) and during isometric leg lifting.

CONCLUSIONS

Wearing abdominal belts raises intra-muscular pressure of the erector spinae muscles and appears to stiffen the trunk. Assuming that increased intra-muscular pressure of the erector spinae muscles stabilizes the lumbar spine, wearing abdominal belts may contribute to the stabilization during lifting exertions.

Genetic diagnostic test of hepatocellular carcinoma by telomerase catalytic subunit mRNA

This study investigated the relationship between telomerase activity and telomere length and between telomerase reverse transcriptase (hTERT) mRNA and telomere length. Both cancerous and non-cancerous tissues were studied in individuals with hepatic carcinoma. In this study, the telomere length in HCC livers had a wide range, no clear significant correlation was found between hTERT mRNA and telomere length. Telomerase activity was more strongly correlated with hTERT mRNA than with telomere length. The correlation between hTERT mRNA and telomerase activity shown here indicates that hTERT mRNA has potential for cancer diagnosis.

[Respiratory symptoms by oral challenge tests with egg white antigens in egg-allergic children]

One hundred and ninety one subjects showing histories of immediate hypersensitive response to egg white ingestion and/or positive IgE antibody titers specific for egg white were enrolled in double-blind placebo-controlled oral challenge with freeze and dried, heated or heated and ovomucoid-depleted egg white antigens. Seventy seven were male and 114 female, and their ages ranged from 11 month to 10 years 5 month; 118 of them had atopic dermatitis, seven had asthma and 33 had both atopic dermatitis and bronchial asthma and 33 had urticaria. One hundred four children developed 147 positive symptoms including 131 immediate reactions and 16 non-immediate reactions by oral challenge tests. Respiratory symptoms were observed in 25 cases (17%) including cough alone in 12 cases (8.2%), and both wheezing and cough in 13 cases (8.8%). These were all observed as immediate reactions and accompanied with dermal symptoms. Frequency of respiratory symptoms correlated with specific IgE antibody titers for egg white. Heated and ovomucoid-depleted egg white was more hypoallergenic that heated or freeze and dried egg white with respect to respiratory symptoms as well as other symptoms. We concluded that respiratory symptoms were provoked through oral challenges with egg white in a part of egg-allergic children.

Metabotropic glutamate receptor subtypes in axon terminals of projection fibers from the main and accessory olfactory bulbs: a light and electron microscopic immunohistochemical study in the rat

Localization of metabotropic glutamate receptor subtypes, mGluR1, mGluR1alpha, mGluR2/3, mGluR4a, mGluR5, mGluR7a, mGluR7b, and mGluR8, was examined in some of the target areas of projection fibers from the main and accessory olfactory bulbs (MOB and AOB) by using subtype-specific antibodies. The superficial layer of the olfactory tubercle and layer Ia of the piriform cortex, the target areas of MOB, showed marked mGluR1-, mGluR5-, mGluR7a-, and mGluR8-like immunoreactivities (-LI), and rather weak mGluR2/3-LI. The periamygdaloid cortical region including the target areas of both MOB and AOB showed intense mGluR2/3-LI as well as marked mGluR1-, mGluR5-, mGluR7a-, and mGluR8-LI. No significant mGluR1alpha-, mGluR4a-, or mGluR7b-LI was seen in these regions. After transection of the lateral olfactory tract, mGluR2/3-, mGluR7a-, and mGluR8-LI were reduced markedly in the target regions on the side ipsilateral to the transection; no significant changes were detected in mGluR1- or mGluR5-LI. Double labeling experiments indicated light and electron microscopically colocalization of mGluR7a- and mGluR8-LI in axon terminals on dendritic shafts of presumed interneurons in the superficial layer of the olfactory tubercle and layer Ia of the piriform cortex. Electron microscopically mGluR2/3-LI was seen in preterminal and terminal portions of axons, whereas mGluR7a- and mGluR8-LI were associated with presynaptic membrane specialization. Immunolabeled axon terminals were filled with round synaptic vesicles and constituted asymmetric synapses with dendritic profiles. The results suggest that glutamate release from axon terminals of projection fibers from MOB and AOB is regulated presynaptically and differentially through mGluR2/3, mGluR7a, and/or mGluR8.

Development of porous apatite ceramic for local delivery of chemotherapeutic agents

An experimental study was conducted on a drug delivery system (DDS), using porous apatite ceramics (PAC): hydroxyapatite block (HAb) [Ca10(PO4)6(OH)2] having a porosity of 35-48% and pore size range of 50-300 microm, and beta-tricalcium phosphate block (TCP) [Ca3(PO4)2] having a porosity of 75-80% and pore size range of 100-400 microm, for sustained release of a chemotherapeutic agent. Methotrexate (MTX) was loaded in the pores of PAC blocks by centrifuging the blocks in MTX solution. Impregnation of MTX in PAC blocks (1 cm3) was confirmed by a magnetic resonance imaging (MRI) study using Gadolinium-DTPA enhancement. The MRI showed high signal intensity in the PAC, which was confirmed by dye loading into the pores. To estimate the MTX-releasing capability of the PAC, the blocks were stored in 3 mL of phosphate-buffered saline (PBS) at 37 degrees C and the PBS was replaced every 48 h. The amount of MTX released was assayed by high-performance liquid chromatography. This study showed that MTX-impregnated PAC (0.63-2.25 mg/block) released the drug in a steady manner and maintained its concentration (0.1-1.0 microg/mL) up to 12 days. This concentration is high enough to be effective against tumor cells. Chemotherapeutic agent-impregnated PAC, prepared by simple centrifugation, could be a valuable form of local chemotherapy when used as a strut graft to repair bone defects. This new DDS material could also be used as an adjuvant to extended curettage and provide a means to reduce the recurrence of tumors without risk of systemic toxicity.

Mice lacking bombesin receptor subtype-3 develop metabolic defects and obesity

Mammalian bombesin-like peptides are widely distributed in the central nervous system as well as in the gastrointestinal tract, where they modulate smooth-muscle contraction, exocrine and endocrine processes, metabolism and behaviour. They bind to G-protein-coupled receptors on the cell surface to elicit their effects. Bombesin-like peptide receptors cloned so far include, gastrin-releasing peptide receptor (GRP-R), neuromedin B receptor (NMB-R), and bombesin receptor subtype-3 (BRS-3). However, despite the molecular characterization of BRS-3, determination of its function has been difficult as a result of its low affinity for bombesin and its lack of an identified natural ligand. We have generated BRS-3-deficient mice in an attempt to determine the in vivo function of the receptor. Mice lacking functional BRS-3 developed a mild obesity, associated with hypertension and impairment of glucose metabolism. They also exhibited reduced metabolic rate, increased feeding efficiency and subsequent hyperphagia. Our data suggest that BRS-3 is required for the regulation of endocrine processes and metabolism responsible for energy balance and adiposity. BRS-3-deficient mice provide a useful new model for the investigation of human obesity and associated diseases.

Generation and characterization of mice lacking gastrin-releasing peptide receptor

Gastrin-releasing peptide (GRP) is a mammalian bombesin-like peptide which is widely distributed in the central nervous system as well as in the gastrointestinal tract. GRP binds to its high affinity receptor (GRPR) to elicit a wide spectrum of biological effects on behavior, digestion, and metabolism. To define the in vivo function of GRPR, we generated GRPR null mutant mice by gene targeting. The intracerebroventricular administration of GRP caused hypothermia in wild-type mice, but not in mutant mice. The GRPR deficient mice showed significantly increased locomotor activity during the dark period, and social responses scored by sniffing, mounting, and approaching behaviors against an intruder. Aggressive scores such as fighting and biting were not altered in the mutant mice. These phenotypes were observed in mice generated from two independent ES cell clones and backcrossed to a C57BL/6J background. The GRPR deficient mice should be useful for studying the bombesin system in vivo.

[Assessment of allergenic activity of heated and ovomucoid-depleted egg white]

We investigated allergenic activity of heated and ovomucoid (OM)-depleted egg white by RAST inhibition tests, skin tests and and oral challenge tests. Freeze-dried egg white, OM and ovalbumin (OA) were coupled with CNBr-activated paper discs. Freeze-dried, heated, and heated and OM-depleted egg white antigens were used as inhibitors in RAST inhibition tests. Freeze-dried egg white significantly inhibited the IgE-binding to freeze-dried egg-white-, OM- and OA-discs. Heated egg white showed a significant inhibition against only OM-disc, but heated and OM-depleted egg white didn't effectively suppress IgE-binding to all discs. Fifty-six patients were subjected for skin tests and 27 patients for oral challenge tests with freeze-dried egg white, heated egg white and heated and OM-depleted egg white. Eighteen of 25 subjects with positive prick tests results to freeze-dried egg white showed negative results to heated egg white. Four of 7 cases with positive prick test results to heated egg white gave negative results to heated and OM-depleted egg white. 20-minutes patch tests showed almost similar results to prick tests. Four of 8 subjects showing positive oral challenge tests with freeze-dried egg white were negative to heated egg white. All of 4 with positive oral challenge tests by heated egg white were negative results to heated and OM-depleted egg white. These evidence indicated that heated and OM-depleted egg white was more hypoallergenic than heated egg white.

Differential presynaptic localization of metabotropic glutamate receptor subtypes in the rat hippocampus

Neurotransmission in the hippocampus is modulated variously through presynaptic metabotropic glutamate receptors (mGluRs). To establish the precise localization of presynaptic mGluRs in the rat hippocampus, we used subtype-specific antibodies for eight mGluRs (mGluR1-mGluR8) for immunohistochemistry combined with lesioning of the three major hippocampal pathways: the perforant path, mossy fiber, and Schaffer collateral. Immunoreactivity for group II (mGluR2) and group III (mGluR4a, mGluR7a, mGluR7b, and mGluR8) mGluRs was predominantly localized to presynaptic elements, whereas that for group I mGluRs (mGluR1 and mGluR5) was localized to postsynaptic elements. The medial perforant path was strongly immunoreactive for mGluR2 and mGluR7a throughout the hippocampus, and the lateral perforant path was prominently immunoreactive for mGluR8 in the dentate gyrus and CA3 area. The mossy fiber was labeled for mGluR2, mGluR7a, and mGluR7b, whereas the Schaffer collateral was labeled only for mGluR7a. Electron microscopy further revealed the spatial segregation of group II and group III mGluRs within presynaptic elements. Immunolabeling for the group III receptors was predominantly observed in presynaptic active zones of asymmetrical and symmetrical synapses, whereas that for the group II receptor (mGluR2) was found in preterminal rather than terminal portions of axons. Target cell-specific segregation of receptors, first reported for mGluR7a (Shigemoto et al,., 1996), was also apparent for the other group III mGluRs, suggesting that transmitter release is differentially regulated by 2-amino-4-phosphonobutyrate-sensitive mGluRs in individual synapses on single axons according to the identity of postsynaptic neurons.

Antibiotic-loaded hydroxyapatite blocks in the treatment of experimental osteomyelitis in rats

A novel drug delivery system for osteomyelitis was developed in which a porous hydroxyapatite block (HAB) is loaded with antibiotic by a centrifugation method. In this study, implantation of HABs loaded with the aminoglycoside antibiotic, arbekacin, were tested in established Staphylococcus aureus osteomyelitis in the proximal tibia of rats after debridement of the marrow cavity. The animals were observed for radiographic signs of infection and tissue was examined histologically. The infections were also evaluated by bone cultures. Bacterial counts were statistically lower in rats implanted with an antibiotic-loaded HAB than in those given a drug-free HAB. Radiographical and histological observations also showed beneficial effects of the antibiotic-loaded implant. The results suggest that the centrifugation method for loading HABs provides a simple drug delivery system. These antibiotic-loaded HABs may be useful for filling grafts in osteomyelitis.

Allergenic activity of heated and ovomucoid-depleted egg white

BACKGROUND

No egg white products have been clearly proven to be hypoallergenic. The role of egg white proteins in allergic reactions to eggs is still debatable.

OBJECTIVE

This study was designed to determine the importance of ovomucoid, an egg white protein, in the development of allergies to egg white.

METHODS

We performed a double-blind, placebo-controlled food challenge in subjects with high levels of IgE antibodies for egg white to compare the allergenicities of heated and ovomucoid-depleted egg white, freeze-dried egg white, and heated egg white. Levels of IgE antibodies for egg white, ovomucoid, ovalbumin, ovotransferrin, and lysozyme were measured in serum by RAST.

RESULTS

Twenty-one of 38 subjects with positive challenge responses to freeze-dried egg white had negative challenge responses to heated egg white, whereas 16 of 17 subjects (94.1%) with positive responses to heated egg white did not respond to the heated and ovomucoid-depleted egg white challenge. The subjects with positive challenge responses to freeze-dried egg white tended to have higher IgE antibody values to ovomucoid than those with negative responses. IgE antibody levels to ovomucoid were significantly higher in subjects with positive responses to a challenge with heated egg white than in those with no response. There were no significant differences in the levels of IgE antibodies to the other proteins, except ovomucoid, in the negative-response and positive-response groups in challenge tests with freeze-dried and heated egg white.

CONCLUSION

The heated and ovomucoid-depleted egg white preparation was less allergenic than heated or freeze-dried preparations. Ovomucoid has a more important role in the pathogenesis of allergic reactions to egg white than other proteins in egg white.

Cloning and expression of the neuromedin B receptor and the third subtype of bombesin receptor genes in the mouse

We cloned the genes for the mouse homologue of the neuromedin B receptor (NMB-R) and the bombesin receptor subtype 3 (BRS-3). Both receptor genes consist of three exons with well-conserved intron-exon borders. Although the NMB-R gene spans more than 10 kb, the BRS-3 gene spans only about 4 kb. Comparison of the mouse and human receptor sequences indicates 90% (NMB-R) and 85% (BRS-3) sequence homology at the amino-acid level. In the adult mouse, the NMB-R mRNA is expressed in the brain, testis, esophagus, intestine and uterus, whereas the BRS-3 mRNA is expressed predominantly in the brain. In the brain, the NMB-R gene expression is prominent in the thalamic and olfactory regions, and the BRS-3 gene is expressed particularly in the hypothalamic region. In mouse testis, the NMB-R gene expression is prominent, and the expression of BRS-3 mRNA is barely detected. In contrast, BRS-3 has been shown to be expressed in rat testis and guinea-pig uterus, therefore it is possible that a different subtype of the bombesin receptor mediates the same response in different species. Together with the mouse GRP-R gene cloned previously, cloning of the mouse NMB-R and BRS-3 genes permits comparison of function and structure of the three bombesin receptor subtypes in the mouse.