Column-switching high-performance liquid chromatography of ofloxacin in human saliva and correlation of ofloxacin level in saliva and serum

A column-switching high-performance liquid chromatography (HPLC) assay was developed for the determination of ofloxacin in saliva. The saliva samples were directly introduced into a C8 HPLC column using a C18 precolumn. Ofloxacin and lomefloxacin as internal standards were detected spectrophotometrically at 300 nm. Determination of ofloxacin was possible in the concentration range 50-3,000 ng/ml, and the limit of detection was 20 ng/ ml. The recovery of ofloxacin added to saliva was 96.9-101.2% with a coefficient of variation of < 2.9%. These pharmacokinetic studies were made of healthy volunteers after treatment with ofloxacin. The maximum concentration of saliva and serum ofloxacin was 513.3-2,053.0 ng/ml and 768.2-3,089.0 ng/ml for dose of 100 mg or 200 mg, respectively. The AUC0-6 was 1,736.8-6,519.9 ng/h/ml in saliva and 2,875.5-10,086.0 ng/h/ml in serum, respectively. The saliva versus serum concentration ratio was 0.4-0.7 for doses of 100 and 200 mg. A good correlation between saliva and serum level of ofloxacin was obtained by this HPLC method (r = 0.949).

Transmembrane regions V and VI of the human luteinizing hormone receptor are required for constitutive activation by a mutation in the third intracellular loop

Gonadotropin receptors are members of the seven-transmembrane (TM) receptor family. Several point mutations in TM V and VI and the intracellular loop 3 (i3) have been identified in the luteinizing hormone (LH) receptor gene, leading to constitutive activation of the receptor. Because gonadotropin receptors are highly conserved, we mutated the follicle-stimulating hormone (FSH) receptor at the corresponding amino acids. However, the FSH receptor mutants showed minimal increases in basal cAMP production. Taking advantage of this difference between the two receptors, we designed chimeric receptors with or without a point mutation in the i3 to identify the region in the LH receptor important for its constitutive activation. Introduction of the point mutation into chimeric receptors containing only TM V to VI from the LH receptor led to major increases in ligand-independent cAMP production. Furthermore, a chimeric receptor with only TM V and VI derived from the LH receptor can be rendered constitutively active by the mutation in the i3 from the FSH receptor. These results suggest that interactions between TM V and VI of the FSH receptor are essential for maintaining the receptor in the more constrained state, whereas interactions between these domains of the LH receptor are permissive for constitutively activating mutations in the i3.

Role of superoxide anions in airway hyperresponsiveness induced by cigarette smoke in conscious guinea pigs

To investigate the involvement of superoxide in airway hyperresponsiveness and bronchoconstriction induced by cigarette smoke (CS), we evaluated the effects of superoxide dismutase (SOD), a scavenger of superoxide anion, and apocynin, an inhibitor of superoxide anion-generating NADPH oxidase in phagocytes, on the airway responses induced by CS in conscious guinea pigs. Airway responsiveness was assessed by PC200Mch, the concentration required to produce a doubling in the baseline specific airway resistance (sRaw) to an inhaled methacholine aerosol, in nonanesthetized spontaneously breathing animals. Before being exposed to ten puffs of CS, animals inhaled either SOD (5,000 units/ml or 25,000 units/ml) or vehicle. Although SOD did not affect PC200Mch in the air control group, this agent significantly reduced the CS-induced airway hyperresponsiveness. Repeated administration of apocynin (12 mg/kg for 4 days) did not affect PC200Mch after exposure to CS. These data suggest that the superoxide from CS was involved in the airway hyperresponsiveness induced by CS, whereas phagocytic reactive oxygen species were not. The data also suggest a potential therapeutic role for antioxidants in airway hyperresponsiveness.

The C-terminal third of the human luteinizing hormone (LH) receptor is important for inositol phosphate release: analysis using chimeric human LH/follicle-stimulating hormone receptors

Gonadotropin and TSH receptors represent a subgroup of seven transmembrane-spanning, G protein-coupled receptors with a large extracellular ligand-binding region. After ligand binding to their receptors, the majority of actions of gonadotropins and TSH are believed to be mediated by the cAMP-protein kinase A pathway. Although formation of inositol phosphates (IP) has been reported after stimulation of rodent gonadotropin receptors, activation of phospholipase C after ligand binding of human LH or FSH receptors has not been investigated. Human gonadotropin receptors were transiently expressed in 293 cells, and the agonist-induced stimulation of IP formation was measured. The LH receptor responded to a saturating dose of human CG (hCG) with a 5.2-fold increase of IPs whereas the FSH receptor responded to a saturating dose of FSH with only a 50% increase. On the basis of these differences and in view of the homologous nature of the two gonadotropin receptors, chimeric receptors were constructed using domain transfer to identify the regions in the human LH receptor important for phosphatidylinositol hydrolysis. Chimeric receptors containing the entire extracellular region of the FSH receptor and the seven transmembrane region plus the cytoplasmic tail of the LH receptor responded to FSH treatment with a 4.7-fold increase in IP accumulation. In contrast, the chimeric receptor with the extracellular region of the LH receptor and the TM region plus the cytoplasmic tail of the FSH receptor responded minimally (50%) to hCG treatment. When the C-terminal third (from TM V to the cytoplasmic tail) of the FSH receptor was replaced with the LH receptor sequence, the chimeric receptor still responded to FSH treatment with a large (6.2-fold) increase in IP release, similar to that of the wild type LH receptor (to hCG), suggesting that C-terminal third of the human LH receptor confers IP signaling ability. This functional domain was further divided into two areas, namely TM V to TM VI and TM VII to the cytoplasmic tail. The chimeric receptors F(I-IV)L(V-VI)F(VII-C)R and F(I-VI)L-VII-C)R, in which these two regions of the FSH receptor were replaced by the corresponding sequences of the LH receptor, responded to FSH treatment with partial increases in phosphatidylinositol hydrolysis (2.0- and 3.7-fold, respectively). Furthermore, when TM VII and the cytoplasmic tail of the LH receptor were replaced with the corresponding sequence of the FSH receptor, this chimeric receptor showed a diminished (2.0-fold) response to hCG in IP release. For all the chimeric receptor constructs analyzed, overall expression, equilibrium binding constants, and adenyl cyclase activation were not altered. Thus, unlike studies using chimeric muscarinic and dopaminergic receptors in which the second and third intracellular loops were found to be important for IP signaling, the entire C-terminal third of the human LH receptor is important for IP release. Future analysis using the chimeric receptor approach should provide new information on the structure-function relationship of gonadotropin, TSH, and other seven transmembrane-spanning receptors.

Crossed projection neurons are generated prior to uncrossed projection neurons in the lateral superior olive of the rat

The present study examined in the lateral superior olive (LSO) of the rat whether LSO neurons projecting to the ipsilateral inferior colliculus (IC) might be generated later than those projecting to the contralateral IC. Rat fetuses were exposed in utero to 5-bromodeoxyuridine (BrdU), a thymidine analogue, to label neurons proliferating at different embryonic stages from day E11 through to E20. Upon reaching adulthood, the rats were given unilateral injections of fluoro-gold (FG), a retrograde fluorescent tracer, into the IC. Subsequently, the tissue sections of the brains obtained from the rats were immunostained for BrdU to simultaneously detect neurons that were BrdU-positive and/or FG-positive. BrdU-positive LSO neurons were found in the rats which had been exposed to BrdU during E12-E16. In E12 and E13 BrdU-exposure cases, the vast majority of doubled-labeled (BrdU-positive and FG-positive) neurons were seen on the contralateral side to the FG injection. In E14, E15 and E16 BrdU-exposure cases, in contrast, all double-labeled neurons were found on the ipsilateral side to the FG injection. The distribution of these double-labeled neurons within the nucleus was diffuse in all the BrdU-exposure cases. Thus, the results indicate that LSO neurons are generated during E12-E16, that the crossed projection neurons are generated 1-4 days earlier than the uncrossed projection neurons, and that no topographical relationships exist between the early- and the late-generated populations of the LSO neurons.

Involvement of superoxide anions in ozone-induced airway hyperresponsiveness in unanesthetized guinea pigs

To evaluate the involvement of superoxide in ozone (O(3))-induced airway hyperresponsiveness, we studied the effects of superoxide dismutase (SOD), a scavenger of superoxide anion, and apocynin, an inhibitor of superoxide anion-generating NADPH oxidase in phagocytes, on the airway responses induced by O(3) in unanesthetized guinea pigs. Airway responsiveness was measured by PC(200)Mch, the concentration required to produce a doubling in the baseline specific airway resistance to an inhaled methacholine aerosol, in spontaneously breathing animals. Before exposure to 3 ppm O(3) for 30 min, animals inhaled either SOD (5000 U/ml) or vehicle for 5 min. Although SOD did not affect PC(200)Mch in the air control group, this agent reduced the O(3)-induced airway hyperresponsiveness. Repeated administration of apocynin (12 mg/kg for 4 days) also attenuated the O(3)-induced airway hyperresponsiveness. These data suggest that superoxide may be involved in the pathogenesis of O(3)-induced airway hyperresponsiveness, possibly through the stimulation of superoxide anions release from bronchoalveolar phagocytes. The data also suggest a potential therapeutic role for antioxidants in oxidant injury by air pollutants.

Compound heterozygous mutations of the luteinizing hormone receptor gene in Leydig cell hypoplasia

The human LH receptor (hLHR) is a member of the G protein-coupled receptors characterized by the presence of seven-transmembrane (TM) helices. Inactivating mutations of the hLHR lead to Leydig cell hypoplasia (LCH), a form of male pseudohermaphroditism resulting from the failure of fetal testicular Leydig cell differentiation. We have identified three mutations of the hLHR in a patient with LCH: deletion of exon 8 (delta Exon 8), A872G transition resulting in Asn291Ser substitution in the extracellular domain, and C1847A transversion resulting in Ser616Tyr substitution in the seventh TM helix. Nucleotide sequencing, gene dosage, and allele-specific amplification analyses revealed that exon 8 deletion and the two missense mutations are present in different alleles of the hLHR. Constructs of mutated hLHR (hLHR-delta Exon8, hLHR-872/1847, hLHR-1847, and hLHR-872) were used to transfect 293 cells, and the properties of the hLHR expressed were examined. Ligand-binding assays failed to detect the expression of hLHR-delta Exon8. Transfectants expressing hLHR-872/1847 demonstrated greatly reduced ligand binding and ligand-induced cAMP accumulation in comparison to those expressing wild type hLHR. Similar reduction in cAMP accumulation was observed in transfectants expressing hLHR-1847, but not hLHR-872 alone. These findings suggest that, in addition to the 7-TM helices, the polypeptide encoded by exon 8 plays an important role in LHR expression and signal transduction. On the other hand, glycosylation of Asn291 may not be critical for these activities. These results also establish that LCH can result from impaired signal transduction due to compound heterozygous mutations. Implications of these mutations on structure-function relationship of the hLHR and the genotype-phenotype correlation in LCH are discussed.

Heterogeneity of activating mutations of the human luteinizing hormone receptor in male-limited precocious puberty

Male-limited precocious puberty (MPP) is a gonadotropin-independent disorder that occurs sporadically or is inherited in an autosomal dominant, male-limited pattern. Recent studies have identified constitutively activating missense mutations in the human luteinizing hormone receptor (hLHR) gene leading to Leydig cell activation and precocious puberty. Patients with sporadic MPP (SMPP) or with different ethnic backgrounds appear to have a greater likelihood of having novel mutations. In the current study we examined genomic DNA from two unrelated cases of SMPP of African-American descent for novel mutations of the hLHR gene. A heterozygous A to C transversion at nucleotide 1723 resulting in substitution of Leu for lle575 in transmembrane helix 6 was identified. Human embryonic kidney cells transfected with cDNA for the mutant hLHR-I575L, created by polymerase chain reaction-based mutagenesis of the wild-type (hLHR-wt) cDNA, exhibited increased basal levels of cAMP production in the absence of agonist, indicating constitutive activation. Surface expression of hLHR-I575L, as reflected by human chorionic gonadotropin binding, was diminished compared to hLHR-wt, while agonist affinity was unaffected. With the exception of two polymorphic bases, no mutation was identified within the coding sequence of the hLHR in the second case of SMPP. We conclude that I575L is a unique constitutively activating mutation that impairs cell surface expression of the receptor but does not alter agonist affinity. Furthermore, mutations of the hLHR gene causing SMPP are highly heterogeneous and may be found in regions other than exon 11 of the hLHR. Last, patients with MPP from different ethnic backgrounds are likely to have novel mutations.

Neurogenesis of subpopulations of rat lumbar dorsal root ganglion neurons including neurons projecting to the dorsal column nuclei

The time of birth of subpopulations of dorsal root ganglion (DRG) neurons was studied with immunohistochemistry for 5-bromodeoxyuridine (BrdU). Pregnant rats were injected with BrdU i.p. to label the neurons on one of the embryonic days (E) E11-E16. When they were adults, the rats were given injections of Fluoro-Gold (FG) into the gracile nucleus to identify DRG neurons projecting to this structure. Following a 5 day survival period, the animals were perfused with aldehyde fixative. Sections from the L3-L5 DRGs were processed for BrdU immunohistochemistry followed by either immunostaining for the antineurofilament antibody RT97, as marker of the light neuronal subpopulation, or histochemical staining for the B4 isolectin from Griffonia simplicifolia I, as marker of the small dark subpopulation. The results indicated that the DRG neurons were generated between E12 and E16. The RT97+ neurons were generated on E12-E15, with a peak at E13. FG+ neurons, the majority of which were RT97+, were also generated on E12-E15. The B4+ neurons were generated on E13-E16, with a peak around E14. The overall pattern of neurogenesis of the DRG neurons showed that the RT97+ neurons were produced prior to the B4+ neurons. These findings are in agreement with earlier observations that the large DRG neurons are generated earlier than the small dark neurons. Our findings also suggest the existence of a third neuronal subpopulation that might be produced at the latest period of DRG neurogenesis at E15-E16.

Expression of biologically active fusion genes encoding the common alpha subunit and the follicle-stimulating hormone beta subunit. Role of a linker sequence

The gonadotropin/thyrotropin hormone family is characterized by a heterodimeric structure composed of a common alpha subunit noncovalently linked to a hormone-specific beta subunit. The conformation of the heterodimer is essential for controlling secretion, hormone-specific post-translational modifications, and signal transduction. Structure-function studies of follicle-stimulating hormone (FSH) and the other glycoprotein hormones are often hampered by mutagenesis-induced defects in subunit combination. Thus, the ability to overcome the limitation of subunit assembly would expand the range of structure-activity relationships that can be performed on these hormones. Here we converted the FSH heterodimer to a single chain by genetically fusing the carboxyl end of the FSH beta subunit to the amino end of the alpha subunit in the presence or absence of a linker sequence. In the absence of the CTP linker, the secretion rate was decreased over 3-fold. Unexpectedly, however, receptor binding/signal transduction was unaffected by the absence of the linker. These data show that the single-chain FSH was secreted efficiently and is biologically active and that the conformation determinants required for secretion and biologic activity are not the same.

A possible role of transient AChE expression in the medial geniculate of developing rats

Acetylcholinesterase (AChE) and calbindin D-28K (CaBP) are transiently expressed in the rat auditory nuclei during the early postnatal period. In the ventral division of the medial geniculate body (MGV), the transient AChE expression in the neuropil is replaced by CaBP expression in the neurones. The time correlation between the up- and down-regulations in these neuro-chemicals suggests some switching over mechanism. A lesion of the inferior colliculus (IC) decreases the AChE reactivity in terminal field of the IC-MGV projections. We here demonstrate that the IC lesion results in CaBP expressions in neurones of the MGV before its normal onset. It is thus possible that the transiently expressed AChE plays an important role in the intercellular signal transduction for neurochemical phenotype expressions.

Atrophic changes of gastric mucosa are caused by Helicobacter pylori infection rather than aging: studies in asymptomatic Japanese adults

BACKGROUND

The current study was designed to evaluate the effect of aging and Helicobacter pylori infection on the gastric mucosa in asymptomatic Japanese adults.

MATERIALS AND METHODS

Eighty-five asymptomatic healthy adults were recruited from a health-screening center in Sapporo. All subjects underwent endoscopy and gastric biopsy, and serum was obtained for IgG antibodies to H. pylori, serum gastrin, and pepsinogen levels.

RESULTS

The prevalence of atrophic change of the gastric mucosa assessed by pathological findings increased with age (49% in the 30- to 39-year-old group compared to 89% in those 60 years and older, p < .001). The frequency of intestinal metaplasia also increased with age (38% in the 30- to 39-year-old group compared to 82% in those 60 years and older, p < .001). In contrast, the frequency of atrophic gastritis and intestinal metaplasia was extremely low in the H. pylori seronegative group regardless of age. Mean serum gastrin level in H. pylori-positive adults was significantly greater than in those who were H. pylori-negative (114.3 +/- 11.2 compared to 65.8 +/- 6.5 pg/ml, p < .03). The serum pepsinogen I-II ratio was significantly lower in those with H. pylori infection than in those without (3.1 compared to 6.6, p < .0001).

CONCLUSIONS

These results suggest that the chronological changes in the gastric mucosa in Japanese individuals are either entirely related to H. pylori infection or the process is greatly accelerated by H. pylori infection.

Peri-implant tissue reaction in bone irradiated the fifth day after implantation in rabbits: histologic and histomorphometric measurements

To evaluate tissue reaction to cobalt 60 irradiation around implant materials used in maxillofacial surgery, 2.0-mm titanium alloy bone screws and 2.0-mm cylindrical solid hydroxyapatite implants were placed in mandibular bone of rabbits and irradiated with a single 15-Gy dose on the fifth postoperative day. Tissue reaction around the implants was examined histologically and histomorphometrically at 7, 14, 28 and 56 days after irradiation. Mature bone was relatively radioresistant, but newly formed bone around both implants was damaged by irradiation in several places. After irradiation, the beginning of bone formation was delayed and the amount of new bone formed was less. Bone-implant contact measured histomorphometrically was less in the irradiated group than in the nonirradiated group. All titanium alloy screws showed bone contact, but two of eight hydroxyapatite implants failed after irradiation, probably the result of loss of primary stability of the cylindrical implants caused by radiation damage to newly formed bone.

[Reversal of portal-systemic encephalopathy by shunt-preserving disconnection of portal and systemic circulation]

Obliteration of portal-systemic shunts surgically or by interventional radiological techniques is fairly effective in reversing intractable portal-systemic encephalopathy (PSE), but is often associated with ascites accumulation and/or formation of esophageal varices. This study reports four patients with incapacitating PSE who were treated by interventional radiological techniques via percutaneous transhepatic route. One case had the shunt embolized directly. In the other three the blockage was placed on the proximal part of the splenic vein, whereby disconnecting the mesenteric-portal blood flow from the systemic circulation while preserving the shunt. The patient of shunt closure showed transient correction of encephalopathy, but developed massive ascites and esophageal varices, encephalopathy recurred, resulting in death from hepatic failure two months after the procedure. In the cases of shunt-preserving disconnection of portal and systemic circulation (SPDPS) immediate and permanent clearing of encephalopathy was achieved without manifestation of ascites or esophageal varices during the follow-up period of 10 to 31 months. The difference of portal pressure between before and after the procedure was 18 mmHg in the shunt-closed patient and 3 mmHg in SPDPS group. We conclude from this limited experience that SPDPS can be an effective and safe method in treating PSE in adequately selected patients.

Protective effect of human ulinastatin against gentamicin-induced acute renal failure in rats

We investigated the protective effect of human ulinastatin against gentamicin-induced acute renal failure in rats. Gentamicin sulfate was subcutaneously injected at a dose of 200 mg/kg for 5 consecutive days. After 3 days administration of gentamicin, a slight decrease in renal function was observed, as well as granulovascular degeneration in the proximal tubular cells as a change in the renal histology. After 5 days administration of gentamicin, a remarkable increase in plasma concentration of creatinine (from 0.27 +/- 0.02 to 1.17 +/- 0.18 mg/dL) and urea nitrogen (from 17.8 +/- 0.6 to 48.8 +/- 5.1 mg/dL) and a significant decrease in creatinine clearance (from 0.64 +/- 0.08 to 0.20 +/- 0.03 mL.100 g-1.min-1) were observed. In addition, an apparent increase in urinary excretion of N-acetyl-beta-D-glucosaminidase and albumin was detected. In the renal histology, proximal tubular necrosis and desquamation of the epithelial cells in the cortex were observed. Furthermore, hyaline cast formation was frequently observed in the outer stripe of the outer medulla. Ulinastatin at doses of 100,000 or 300,000 U/kg was coadministered intraperitoneally just after each gentamicin injection. Ulinastatin treatment showed a dose-dependent suppression of gentamicin-induced biochemical alterations and histological changes. After 5 days treatment with 300,000 U.kg-1.day-1 of ulinastatin, the magnitude of gentamicin-induced changes in renal function was significantly lessened, by 45-80%. The score for proximal tubular injuries and the rate of hyaline cast formation were also significantly lower in the same group of animals than those in the group treated with gentamicin alone. In the in vitro study, ulinastatin at 10-300 U/mL showed a concentration-dependent suppression on the fragility of the lysosomal membrane isolated from rat kidney cortex during hypotonic treatment. These results indicate that human ulinastatin has a prominent protective effect on gentamicin-induced acute renal failure in rats, and the lysosomal membrane stabilizing effect is possibly involved as a mechanism of this action.

Acute and subacute inhalation toxicity of dichlorosilane in male ICR mice

Using male ICR mice, the LC50 and acute and subacute inhalation toxicity of dichlorosilane (SiH2Cl2, DCS) and the fate of DCS released into the air were investigated. DCS resolved and minute particles including silicon and chloride were observed, when DCS was released into the air. Most particles were under 1 micron in diameter. The LC50 of DCS at 4-h exposure was 144 ppm (nominal concentration). In the acute inhalation study, ten mice in each group were exposed to 64 ppm (nominal concentration) DCS for 1, 2, 4 or 8 h. Body weight loss, wheezing and piloerection were observed in mice exposed for 2 h or more. Histopathologically, injury to the nasal mucosa and trachea were observed in all exposed mice. Mice exposed to 32 ppm (nominal concentration) DCS for 2 or 4 weeks also exhibited depression of body weight gain, wheezing and piloerection. Squamous metaplasia of the nasal mucosa and tracheal epithelium was observed in both 2- and 4-week exposure groups. Exposure to DCS was irritant or corrosive to the respiratory tract with both acute and subacute inhalation. Apart from silane (SiH4), toxic effects of DCS seem to be characterized by chloride compounds derived from DCS.

[Pulmonary tuberculosis with systemic lymph node swelling]

A 31-year-old woman was admitted to our hospital because of cervical and axillar lymph node swelling. A chest X-ray film showed many nodular shadows and a cavity in the left upper lung field. The tuberculin test was positive. Transbronchial lung biopsy and cervical lymph node biopsy were done. Examination of the biopsy specimens revealed epithelial granulomas with caseous necrosis. Thus, pulmonary tuberculosis with systemic lymph node swelling was diagnosed. Examinations during the patient's hospital stay showed that she was not an immunocompromised host. Pulmonary tuberculosis with systemic lymph node swelling occurs only rarely in a non-immunocompromised host.

Electron microscopic study of synaptogenesis and myelination of the olfactory centers in developing rats

Development of the central olfactory system was studied in the rat with an electron microscope at three main structures: the olfactory bulb, the lateral olfactory tract, and the primary olfactory cortex (the piriform cortex). As a parameter of development, the synaptic density was examined quantitatively in the bulbar glomerulus and layer Ia (termination of bulbofugal fibers) of the piriform cortex. which are the key stations of the olfactory pathway. The synaptic densities in the glomerulus and those in layer Ia were 5.7% and 4.6% on embryonic day 19, 15.8% and 12.5% on postnatal day (P) 0, and 57.3% and 37.2% on P10, as compared with the adult (100%). As another parameter of development, the density of myelinated axons in the lateral olfactory tract was examined quantitatively. The densities of myelinated axons in the tract were 0% on P5, 15.1% on P10, and 73.5% on P21 of the adult density. Maturation in the tract was still progressing, even at P21, in terms of bundle formation and the thickness of myelin sheaths. The results show that synaptogenesis in the bulbar glomerulus is followed by synaptogenesis in layer Ia of the piriform cortex, and that myelination in the lateral olfactory tract occurs over a prolonged period, even in the stages after P21.

[Arterial plasma keton body levels during isoflurane anesthesia and surgery]

The authors measured arterial plasma levels of acetoacetate, 3-hydroxybutyrate, free fatty acid and the blood levels of lactate and glucose to evaluate fat metabolism during isoflurane anesthesia and surgery in twenty patients who ranged in age from 17 to 67 years. They underwent non-abdominal surgery (orthopedic surgery) or abdominal surgery (gastrointestinal or gynecological surgery). The operation started at 9 AM following starvation after 9 PM of the day before surgery. Anesthesia was induced with intravenous thiopental followed by intravenous succinylcholine to facilitate tracheal intubation, and maintained with isoflurane in 50 % nitrous oxide and 50 % oxygen. Vecuronium was given intravenously during surgery. Lactated Ringer's solution at a speed of 5-15 ml.kg-1.h-1 was also administered intravenously throughout the procedures. Patients who had received glucose solution or blood transfusion were excluded. Plasma acetoacetate and 3-hydroxybutyrate levels increased significantly with surgical stimulation in both groups and they were slightly higher in the abdominal group than those in the non-abdominal group. However there was no statistical difference in plasma keton body levels between the groups. Mild increases in plasma free fatty acid and blood lactate levels were detected during surgery in both groups to the same extent. Blood glucose increased significantly during surgery in both groups and the increase was statistically higher in the abdominal group than that in the non-abdominal group. The findings suggest that there is no difference in fat metabolism between non-abdominal and abdominal groups during surgical intervention lasting as long as 3 hours when patients are starved and do not receive any glucose during surgery.

A nonsense mutation of the human luteinizing hormone receptor gene in Leydig cell hypoplasia

Leydig cell hypoplasia (LCH) is a form of male pseudohermaphroditism in which Leydig cell differentiation and testosterone production are impaired. This report describes the first case of a nonsense mutation (A1635C) in exon 11 of the human luteinizing hormone receptor (hLHR) gene in two sisters with LCH. This mutation causes loss of function of the receptor by introducing a stop codon at residue 545 in transmembrane helix 5 of the hLHR. Surface expression of the truncated hLHR (hLHR-t545) in human embryonic kidney cells stably transfected with cDNA encoding hLHR-t545 was diminished compared to the wild-type hLHR and hCG-induced cAMP accumulation was impaired. These results establish that single base mutations in exon 11 of the hLHR gene can produce inactivation as well as activation of the hLHR. Furthermore, they demonstrate that functional domains between transmembrane helix 5 and the C-terminal cytoplasmic tail of the hLHR are required for normal cell surface expression of the receptor and signal transduction.

Relationship between Helicobacter pylori infection, atrophic gastritis and gastric carcinoma in a Japanese population

AIM

To evaluate the possible relationship between Helicobacter pylori infection and gastric carcinoma, and its precursor lesion, intestinal metaplasia, in a Japanese population.

SUBJECTS AND METHODS

H. pylori infection was identified by the presence of anti-H. pylori immunoglobulin (Ig)G. The frequency of H. pylori infection was compared in 109 patients with gastric carcinoma, the same number of patients with atrophic gastritis and asymptomatic controls matched for age, sex and place of birth. To study the relation between H. pylori and intestinal metaplasia, sera and gastric antral and corpus mucosal biopsies were obtained from 58 asymptomatic controls, 92 patients with chronic gastritis and 80 patients with peptic ulcer.

RESULTS

The presence of IgG antibody to H. pylori was significantly more frequent in those with gastric carcinoma than in asymptomatic controls (87.2 versus 74.3%; odds ratio 2.4; 95% confidence interval 1.2-4.8). The positive rates of H. pylori IgG antibody were 80.7% in patients with atrophic gastritis. Mean serum gastrin and pepsinogen II levels in H. pylori-positive patients were higher than those in H. pylori-negative patients. Serum gastrin and pepsinogen I levels were significantly higher in controls than gastric carcinoma patients (P < 0.01 and P < 0.05, respectively). Serum pepsinogen I:II ratios were significantly lower in controls than in gastric carcinoma patients (P < 0.01). Intestinal metaplasia was strongly associated with H. pylori infection, and was only found in patients with IgG antibodies to H. pylori.

CONCLUSIONS

These results suggest that H. pylori infection is associated with the development of gastric cancer by providing a suitable environment for carcinogenesis of the gastric mucosa, such as gastric atrophy and intestinal metaplasia.

Anatomical plasticity in the medial superior olive following ablation of the inferior colliculus in neonatal and adult rats

We evaluated the consequences of unilateral ablation of the inferior colliculus (IC) upon the ascending projection from the medial superior olive (MSO) to the IC. Ablation of the IC was performed in rats aged between postnatal day 1 (P1) and maturity. All the rats were given injections of Fluoro-Gold (FG) into the ipsilateral IC at birth (P0) (before the ipsilateral IC was ablated in any case) so that growth of early-developing axons to the ipsilateral IC could be examined for any labeled neurons in the ipsilateral MSO. Upon reaching adulthood, the rats received injections of Fluoro-Ruby (FR) into the contralateral (intact) IC so that aberrant crossed projections to the intact IC could be examined for any labeled neurons in the ipsilateral MSO. These rats were killed 2 days after FR injections. The number of surviving cells in the ipsilateral MSO were counted in Nissl-stained sections for quantitative analysis of retrograde degeneration. The results show that: (1) the total number of neurons was reduced to 64-34% in the ipsilateral MSO as a result of IC ablation; (2) cell reduction by retrograde degeneration followed a U-shaped curve with a maximal effect in rats operated at P7 (reduced to 34%); (3) adult ablation of the IC led to retrograde degeneration that was less severe than that in late neonatal (P7) ablation; (4) an aberrant projection from the MSO to the contralateral IC occurred in rats operated at P1 and P3 but not in rats operated at P7 or maturity. Thus, our findings suggest that growth of late-developing axons is a major factor in the plasticity of this system of projection.

Postnatal development of the projection from the medial superior olive to the inferior colliculus in the rat

Normal projection development from the medial superior olive (MSO) to the inferior colliculus (IC) was examined by injecting Fluoro-Gold (FG), a retrograde tracer, into the IC unilaterally at postnatal days 0 (P0), P3, P7 and maturity. The rats were killed 1 day after FG injection. At all ages, labeled neurons in the MSO appeared on the ipsilateral side only, as in adult controls. The total number of MSO neurons counted in Nissl-stained sections was constant throughout the postnatal periods. The labeled frequency index of MSO neurons was increased stepwise (from 35% to 90%) with increasing postnatal stages (from P0 to adulthood), suggesting differential growth of early- and late-developing axons.

Visualization of site-specific recombination catalyzed by a recombinase from Zygosaccharomyces rouxii in Arabidopsis thaliana

Excision of a DNA segment can occur in Arabidopsis thaliana by reciprocal recombination between two specific recombination sites (RSs) when the recombinase gene (R) from Zygosaccharomyces rouxii is expressed in the plant. To monitor recombination events, we generated several lines of transgenic Arabidopsis plants that carried a cryptic beta-glucuronidase (GUS) reporter gene which was designed in such a way that expression of the reporter gene could be induced by R gene-mediated recombination. We also made several transgenic lines with an R gene linked to the 35S promoter of cauliflower mosaic virus. Each transgenic line carrying the cryptic reporter gene was crossed with each line carrying the R gene. Activity of GUS in F1 and F2 progeny was examined histochemically and recombination between two RSs was analyzed by Southern blotting and the polymerase chain reaction. In seedlings and plantlets of F1 progeny and most of the F2 progeny, a variety of patterns of activity of GUS, including sectorial chimerism in leaves, was observed. A small percentage of F2 individuals exhibited GUS activity in the entire plant. This pattern of expression was ascribed to germinal recombination in the F1 generation on the basis of an analysis of DNA structure by Southern blotting. These results indicate that R gene-mediated recombination can be induced in both somatic and germ cells of A. thaliana by cross-pollination of parental transgenic lines.