Imipenem and cephem resistant Pseudomonas aeruginosa carrying plasmids coding for class B beta-lactamase

From October 1988 to January 1992, nine isolates of Pseudomonas aeruginosa carrying transferable plasmids encoding imipenem-hydrolyzing beta-lactamase (pI = c. 9.5) were recovered from nine different patients in a neurosurgical ward of a hospital in Japan. The beta-lactamase activities of the sonicated extracts from the transconjugants were inhibited by EDTA and this was partially reversible by the addition of zinc cation. The substrate specificity and pI of the beta-lactamase were similar to those of the metallo beta-lactamases from P. aeruginosa and Serratia marcescens TN9106. All strains were resistant to imipenem, carbenicillin and antipseudomonal cephems including ceftazidime, cefsulodin, cefpirome, while four and five strains were susceptible to piperacillin and aztreonam, respectively. Both low level imipenem resistance and high level cephem resistance were co-transferred with the production of metallo beta-lactamase, while resistance to piperacillin, aztreonam, and high level imipenem-resistance were not selected. Production of chromosomal cephalosporinase in piperacillin resistant strains was derepressed, and production of outer membrane protein of D2 was diminished in highly imipenem resistant strains. Six strains were isolated in 1991, and the amounts of antipseudomonal agents, especially imipenem, used in the neurosurgical ward increased markedly in this year. Only three of the nine isolates had the same serotype, pyocin type and phage type. Our results suggest that the repeated isolation of imipenem and cephem-resistant P. aeruginosa producing metallo beta-lactamase was related to the high usage of antipseudomonal beta-lactam antibiotics such as imipenem, and was exacerbated by the dissemination of a plasmid.

Randomized trials between behenoyl cytarabine and cytarabine in combination induction and consolidation therapy, and with or without ubenimex after maintenance/intensification therapy in adult acute myeloid leukemia. The Japan Leukemia Study Group

PURPOSE

We analyzed complete remission (CR), disease-free survival (DFS), and event-free survival (EFS) rates in two groups of patients treated with either N4-behenoyl-1-beta-D-arabinosylcytosine (BHAC) or cytarabine, and analyzed DFS with or without ubenimex, a biologic response modifier.

PATIENTS AND METHODS

Newly diagnosed patients with acute myeloid leukemia (AML) were randomized to receive either BHAC or cytarabine as remission-induction combination chemotherapy and two courses of consolidation therapy. After maintenance/intensification therapy, patients in CR were randomized to receive either ubenimex and no drug.

RESULTS

Of 341 patients registered, 326 were assessable. The age of assessable patients ranged from 15 to 82 years (median, 48). The overall CR rate was 77%: 72% in the BHAC group and 81% in the cytarabine group, and there was a significant difference between the two groups (P = .035, chi 2 test). The predicted 55-month EFS rate of all patients was 30%: 23% in the BHAC group and 35% in the cytarabine group, with a significant difference between groups (P = .0253). The predicted 55-month DFS rate of all CR patients was 38% and that of CR patients less than 50 years of age was 47%. There was no significant difference in DFS between the ubenimex group and the group that did not receive ubenimex.

CONCLUSION

Analyses of our clinical trial showed that the use of BHAC in remission-induction therapy and in consolidation therapy resulted in poorer CR and EFS rates in adult AML patients compared with the use of cytarabine at the doses and schedules tested. Immunotherapy with ubenimex after the end of all chemotherapy did not improve DFS.

In vitro antibacterial properties of T-5575 and T-5578 novel parenteral 2-carboxypenams

T-5575 and T-5578, novel 2-carboxypenams in which a carboxyl group has been introduced into the C-2 beta position of the nucleus, were evaluated for their in vitro antibacterial properties. The spectrum of activity of T-5575 was similar to that of aztreonam. However, it showed stronger activities than those of aztreonam against most gram-negative bacteria. T-5575 also showed potent activities against isolates of Enterobacter cloacae, Citrobacter freundii, and Pseudomonas aeruginosa resistant to ceftazidime, with MICs at which 90% of the isolates were inhibited of 0.39, 0.39, and 3.13 microgram/ml, respectively. T-5578 showed moderate levels of activity against gram-negative bacteria, compared with those of T-5575. Its activity against P. aeruginosa, however, was superior to those of T-5575 and the reference drugs tested. The most characteristic feature of T-5578 was its potent activities against ceftazidime-, imipenem-, and gentamicin-resistant P. aeruginosa isolates, with MICs at which 90% of the isolates were inhibited at 0.39, 3.13, and 3.13 microgram/ml, respectively. These two compounds were unfortunately poorly active against gram-positive bacteria, such as Staphylococcus aureus and streptococci. Both compounds were found to be stable for hydrolysis by various kinds of beta-lactamases and to have low affinities for these enzymes, with Ki values of > 100 microM. These novel penams bound most tightly to penicillin-binding protein 3 of Escherichia coli and P. aeruginosa. These results indicate that T-5575 and T-5578 can be regarded as promising 2-carboxypenams specially targeted against gram-negative pathogens.

[Bilateral simultaneous spontaneous pneumothoraces associated with Alport's syndrome]

A 45-year-old man with Alport's syndrome presented with chest pain and dry coughing. A chest roentgenogram showed bilateral simultaneous spontaneous pneumothoraces. Possible causes such as pulmonary bullae were not detected. A partial defect in type IV collagen, which is involved in repair of the basement membrane, may have played a role in the etiology of pneumothoraces in this patient.

Effects of hyper- and hypoglycemia on blood growth hormone level in free-feeding rats with anterolateral deafferentation of the medial basal hypothalamus

In rats with anterolateral deafferentation of the medial basal hypothalamus, the growth hormone (GH) level in the blood showed irregular and small fluctuations instead of the usual high bursts and low trough level, and the baseline GH level was higher than that in sham-operated rats. Continuous infusion of a glucose solution to operated rats increased the baseline level, GH pulse and pulse amplitude. I.v. bolus injection of the glucose solution resulted in a significant but transient increase in GH level. Insulin-induced hypoglycemia decreased the blood GH level in operated rats more effectively than in sham-operated ones and that was prevented by simultaneous infusion of glucose. Since SS influence on GH secretion had been largely eliminated in rats with anterolateral deafferentation of the medial basal hypothalamus, it is highly unlikely that the effects of hyperglycemia or hypoglycemia on GH secretion were the consequence of altered SS secretion.

Central glucoprivation evoked by administration of 2-deoxy-D-glucose induces expression of the c-fos gene in a subpopulation of neuropeptide Y neurons in the rat hypothalamus

Central glucoprivation evoked by the intracerebroventricular administration of 2-deoxy-D-glucose (2DG) induces eating and suppresses growth hormone (GH) secretion in rats. To elucidate the hypothalamic mechanism of these phenomena, the induction of c-fos gene expression was examined by in situ hybridization using rats with centrally administered 2DG. Autoradiography on X-ray film showed that c-fos gene expression was transiently induced in discrete hypothalamic regions; namely the paraventricular nucleus, arcuate nucleus (ARC), the surrounding regions of the third ventricle dorsal to the ARC, and the periventricular nucleus (PeV). The time course of the expression was different in these nuclei. Double-label in situ hybridization for c-fos mRNA and neuropeptide Y (NPY) or somatostatin mRNAs revealed that 20% of the NPY neurons in the ARC expressed the c-fos gene, while a small population of somatostatin neurons (6.1% in the ARC and 2.6% in the PeV) expressed the c-fos gene following 2DG administration. Since NPY is an orexigenic neuropeptide and has an inhibitory effect on GH secretion, the data suggest that the activation of a subpopulation of NPY neurons in the ARC contributes, in part, to the increased food intake and suppression of GH secretion after central glucoprivation evoked by 2DG.

MR and CT appearance of urethral clear cell adenocarcinoma in a woman

We present a case of clear cell adenocarcinoma of the female urethra that has been evaluated with CT and MRI. The lesion was a well-demarcated mass surrounded with peripheral enhancement on CT. On MRI a sharply marginated mass was located in the midurethra, giving rise to a smooth elevation of the bladder base. On T2-weighted imaging, the lesion was hyperintense, being surrounded by a ring of lower signal intensity at the periphery. A central urethral dot of lower signal intensity traversed the anterior one-third of the mass but was preserved in its entire length.

[Clinicopathological evaluation of etoposide or estramustine phosphate in castrated patients with advanced prostatic cancer]

BACKGROUND

We conducted a multicentric randomized trial to compare bilateral orchiectomy versus bilateral orchiectomy plus etoposide or estramustine phosphate as first-line therapy for advanced prostatic cancer (stage D2).

METHODS

From January 1991 to December 1992 a total of 46 newly diagnosed cases (registered cases) of advanced (stage D2) prostatic cancer was randomized into 3 groups as follows; Group A: bilateral orchiectomy and 25 mg/day of etoposide every 2 weeks for 6 months. Group B: bilateral orchiectomy and 560 mg/day of estramustine phosphate for 6 months. Group C: bilateral orchiectomy alone. One of group A and one of group B were ineligible cases, so 44 were eligible. In the eligible cases, ages were ranged from 54 to 90 (mean of 71.2) years old. No significant difference of patients' characteristics was found among 3 groups and median follow-up period was 25 months. Response was evaluated based on the response criteria according to Japanese urological association. Specifically, a central pathologist who blinded to the treatment was employed for evaluating pathological response at six months.

RESULTS

Of the 44 eligible patients, 33 and 25 were evaluated for clinically and pathological analyses, respectively. Clinical response rates were 80% (12/15) of group A, 100% (4/4) of group B and 78.6% (11/14) of group C. No significant difference in the clinical response and survival rate was shown among the three groups. Significantly higher frequencies of side effects were noted in the grop B compared to the other two groups (p < 0.05) and cardiovascular complications were the most frequent in group B. Favorable pathological response was obtained in all of group B, but not statistically significant compared with 7/21 (33.3%) of response rate in group A and C. The pathological response was significantly correlated with the clinical one in all patients (p < 0.01). While 8 of 11 patients (73%) with pathological response grade 1, 2 and 3 achieved clinical PR (partial response) or CR (complete response), only 5 of 14 (36%) with grade 0 received PR or CR.

CONCLUSIONS

We conclude that low dose administration of etoposide or estramustine phosphate dose not improve clinical response and survival in a short term in castrated patients, but increases the adverse effects due to the drugs in these patients. In addition, the pathological evaluation at 6 months after treatment appears to reflect the clinical response at that time in newly diagnosed patients with advanced prostatic cancer.

Evaluation of chitin and chitosan on open would healing in dogs

Analysis on the accelerating effects of open wound healing by chitin and chitosan were carried out in dogs. Two, square, full-thickness wounds of skin (2 x 2 cm2) were created on the each dog's both sides of dorsal midline at 0, 14, 21, and 24 days. In one dog, one wound (left side) was treated with chitin (chitin group) and the other wound (right side) was not treated (control group). In another dog, one wound (left side) was treated with chitosan (chitosan group) and the other wound (right side) was not treated (control group). At 28 days after initial wounding, each wound site including surrounding tissue was taken for macroscopic and histological observations. Reepithelialization tended to be greater in chitin and chitosan groups than in the control group. However, when the scores of reepithelialization and granulation tissue were evaluated statistically, there was no significant differences in three groups during experimental period. Number of inflammatory cells was greater statistically in level in the control group than those in chitin and chitosan groups at 28 days after wounding. Many rete ridges were observed in the control group but very few in the another groups.

Effects of chitosan on experimental abscess with Staphylococcus aureus in dogs

An abscess was developed experimentally by a subcutaneous inoculation of Stapylococcus (S.) aureus T-6 with a 4-cm silk suture in dogs. After draining the pus, the abscess was treated with a suspension of finely granulated chitosan (chitosan group), ampicillin (ampicillin group), or saline (control group) (Day 0). The chitosan group was further divided into 3 subgroups (0.01, 0.1, and 1.0 mg/subgroups). Similar treatment was repeated after 4 days (Day 4), followed by euthanasia on Day 8. The wound cavity contraction rate was calculated by measuring the wound cavity diameter by a sound on Days 0, 4 and 8. The wound cavity contraction rate was significantly higher in the ampicillin, 0.1 mg chitosan, and 1.0 mg chitosan groups than in the 0.01 mg chitosan and control groups on Days 4 and 8 (p < 0.05). In the 0.1 and 1.0 mg chitosan groups, the abscess healed completely in 6 out of 11 (55%), and 9 out of 10 cases (90%), respectively, by Day 8. In the ampicillin group, 4 out of 10 cases (40%) healed completely by Day 8. No healing occurred in the 0.01 mg chitosan and control groups. Histologically, the granulation tissue formed had abundant vascularization in the 0.1 and 1.0 mg chitosan groups on Day 8.

[Clinical value of rapid clearance in resting sestamibi cardiac SPECT in patients with acute myocardial infarction]

Resting 99mTc sestamibi (MIBI) SPECT and exercise-reinjection thallium-201 (T1) SPECT were performed in fourteen patients with acute myocardial infarction (AMI). MIBI SPECT were obtained 90 min (MIBI-90) and 300 min (MIBI-300) after injection of 370 MBq of MIBI at rest. MIBI-90 and MIBI-300 were compared with exercise T1 imaging (T1-EX) and T1 reinjection imaging (REINJ). Each SPECT image was divided into 22 segments and myocardial uptake was scored visually. Abnormal perfusion defects were observed in 94 myocardial regions. Worsening of the score was observed in 79 segments (84%) on MIBI-300 compared with MIBI-90. Total MIBI-300 uptake score per person was significantly greater than that at MIBI-90 (14.8 +/- 8.6 vs. 7.7 +/- 7.9, p = 0.001). The concordance rate of defect score between MIBI-90 and REINJ was significantly higher than that between MIBI-300 and REINJ (55% vs. 17%, p = 0.001). In nine patients without recanalization of an infarct-related artery, perfusion defects were seen in 74 segments. The concordance rate of defect scores between MIBI-300 and T1-EX was significantly higher than that between MIBI-90 and T1-EX (45% vs. 16%, p = 0.001). In conclusion, rapid clearance of MIBI was observed frequently in patients with AMI. MIBI-90 and MIBI-300 may reflect myocardial viability and areas at risk for AMI, respectively.

Diurnal variation in luteinizing hormone-releasing hormone and beta-endorphin release in pituitary portal plasma during the rat estrous cycle

In this study, we investigated the pattern of both LHRH and beta-endorphin (beta-EP) secretion from the median eminence of cyclic female rats during the estrous cycle by collecting pituitary portal blood for hormone measurements by RIA. On diestrus, proestrus, or estrus (0900 h or 1300 h), rats were hypophysectomized (in order to prevent contamination of portal beta-EP with pituitary beta-EP) and were given a 50-60-min resting period of postsurgical recovery prior to blood sampling. Between 1000 h and 1800 h of the same day, pituitary portal blood samples were collected at 10-min intervals from these animals under Saffan anesthesia. Hormone RIA data revealed that LHRH and beta-EP levels in the portal plasma ranged from 25 to 600 pg/ml and from 0.6 to 4.6 ng/ml, respectively, whereas no discernible amounts of these hormones were detected in the peripheral plasma. Analysis further revealed that secretion of both LHRH and beta-EP showed a diurnal rhythmicity and that both neuropeptides were secreted in a pulsatile manner on each day of the cycle, with most dramatic changes seen in female rats on proestrus. In proestrus rats, portal plasma levels of beta-EP were highest during 1000-1500 h and lower around 1600-1800 h. In contrast, morning and early afternoon values of LHRH were obviously higher in rats on proestrus than in animals on other days of the cycle, and an even greater rise in portal plasma levels of LHRH occurred in late afternoon on proestrus, when beta-EP values were lowest.(ABSTRACT TRUNCATED AT 250 WORDS)

Caloric intake stimulates growth hormone secretion in food-deprived rats with anterolateral deafferentation of the medial basal hypothalamus or administered antiserum to somatostatin

In rats, food deprivation inhibits episodic growth hormone (GH) secretion. On the basis of previous studies, we hypothesized that during a recovery from prolonged fasting, caloric intake stimulates the release of GH-releasing factor (GRF) and this process does not depend on the specific macronutrients in the meal, while protein in the meal acts to restore characteristic ultradian rhythmicity of GH secretion. To test this hypothesis, the effect of caloric intake on GH secretion was examined in fasted adult male Wistar rats devoid of somatostatin (SS) influence on GH secretion either by anterolateral deafferentation (ALC) of the medial basal hypothalamus (MBH) or administration of anti-SS goat serum (ASS). Rats were provided with an indwelling right atrial cannula and were deprived of food for 72 h. ALC was performed 2 weeks prior to the study. ASS was given i.v. 8 h and 7 h prior to refeeding, respectively. Serial blood specimens were collected every 10 min. In rats with ALC (ALC rats) or rats given ASS (ASS rats), the blood GH level revealed irregularly occurring small fluctuations, instead of the usual high bursts and low trough level. The baseline GH level and the mean GH level of fasted ALC rats or fasted ASS rats were significantly lower than those of fed ALC rats or fed ASS rats. Feeding the isocaloric mixed meal, the protein meal or the protein-deficient meal increased the GH pulse frequency, the pulse amplitude, the baseline GH level and the mean GH level in 72-h fasted ALC rats. These changes in GH secretory pattern persisted during the period of observation and were independent of the type of meal ingested. Following feeding the mixed meal, similar changes in the GH secretory pattern demonstrated in 72-h fasted ALC rats were also observed in 72-h fasted ASS rats, suggesting that the stimulation of GH secretion following caloric intake is not limited to ALC rats. Since the influence of SS on GH secretion has been largely eliminated in ALC or ASS rats, it is highly unlikely that the augmentation of GH secretion following feeding after prolonged food deprivation was the consequence of inhibition of SS secretion. Although GRF measurement was not performed, it is conceivable that the signal of caloric intake is conveyed to the MBH and acts to stimulate GRF release.

[Serum protein binding of T-3761]

We investigated the extent of the binding of T-3761 to serum protein and obtained the following results. 1. The binding rates of T-3761 to serum protein from various animals and human were 16.9-27.7%, and a little higher than those of ciprofloxacin and ofloxacin. 2. The binding rates of T-3761 to human serum protein were 19.1-23.8% at concentrations of 0.25-20 micrograms/ml. 3. The binding rates of T-3761 lowered as the decrease of protein concentration. 4. The binding rates of T-3761 (2 micrograms/ml) to human serum protein were 12.4, 21.3 and 32.1% at pH 7.0, 7.4 and 8.0, respectively, showing the effect of the pH. 5. The binding of T-3761 to human serum protein was reversible. 6. In vivo binding rates of T-3761 in rabbits after a single oral administration of 20 mg/kg were 26.1-33.2%, which were similar to those obtained in vitro.

Increase of intracellular free [Ca2+] in single human motile spermatozoa treated with human follicular fluid

The intracellular free [Ca2+] concentration ([Ca2+]i) in individual human sperm was measured using a fluorescent Ca2+ indicator. In 18 of 23 motile sperm (78.3%), [Ca2+]i increased significantly and promptly after addition of 20% human follicular fluid (hFF), but in the others it did not increase. The mean resting [Ca2+]i level of sperm in which [Ca2+]i increased after addition of 20% hFF (the influx group) was significantly lower than those in which it did not increase (112.8 +/- 40.1 nM vs. 156.9 +/- 13.5 nM, p < .05). After addition of 20% hFF, the mean [Ca2+]i in the influx group reached a peak value of 210.7 +/- 24.7 nM within 30 s and then decreased slowly; the mean [Ca2+]i values 1, 5, 10, and 15 min after addition of 20% hFF were 179.3 +/- 31.4, 174.3 +/- 30.2, 172.5 +/- 27.8, and 175.1 +/- 27.2 nM, and all values were significantly higher than the resting level (p < .01). The frequency distribution of [Ca2+]i after addition of 20% hFF was shifted toward higher concentrations (p < .01). However, the addition of 20% hFF did not increase the percentage of live acrosome reaction (before 3.8 +/- 0.9% vs. after 2.9 +/- 0.5%, respectively). Thus, hFF increased [Ca2+]i in about 80% of the motile sperm. Relatively high [Ca2+]i levels persisted for at least 10-15 min after its addition. However, hFF did not trigger a rapid response in acrosome reaction.

[Absorption, distribution, metabolism and excretion of T-3761, a new quinolone derivative, in experimental animals]

We studied the absorption, distribution, metabolism and excretion of T-3761, a new quinolone derivative, in experimental animals. The following results were obtained. 1. The peak serum levels of T-3761 after a single oral administration to various fasting animals at a dose of 5 mg/kg were high in the order of rats, dogs, mice and rabbits, showing favorable absorption in all animals except for rabbits. In mice and rats, T-3761 showed higher peak serum levels than ofloxacin and ciprofloxacin but T-3761 were more rapidly eliminated from serum than ofloxacin and ciprofloxacin. 2. Tissue concentrations of T-3761 in rats were similar to those of ofloxacin but its ratio of tissue to serum levels were lower than those of ofloxacin. 3. Urinary excretion of T-3761 as active form until 24 hours after oral administration was 27.3%, 63.1%, 41.0% and 63.3% in mice, rats, rabbits and dogs, respectively. Only unchanged T-3761 was detected as active form in urine of all animals tested. In rats, urinary concentrations until 2 hours after administration were higher than those of ofloxacin. 4. Biliary excretion of T-3761 in mice and rats were 2.9% and 1.4% as active form. 5. The absorption of T-3761 was not different in male and female rats or 8 and 14 weeks old rats. The meal lowered absorption of T-3761 in rats. There was no significant difference in serum levels, urinary excretion and distribution to tissues after multiple administration of T-3761 comparing with its single administration. 6. In rats with liver dysfunction induced by D-galactosamine, the serum levels and urinary excretion were slightly higher than in normal rats. On the other hands, in rats with kidney dysfunction induced by HgCl2, the serum levels were significantly higher and urinary excretion of T-3761 was significantly lower than in normal rats. Above results show that T-3761 has unique characteristics in absorption, excretion and distribution after oral administration to animals among new quinolones, i.e., T-3761 was eliminated rapidly and poorly distributed to tissues but showed superior absorption and high peak serum levels.

[Microbiological assay method for T-3761 concentration in body fluids]

A microbiological assay method for measurement of T-3761 and its stability in body fluids were investigated. The paper disc method proved suitable for this assay using Escherichia coli Kp as a test organism and commercially available heart infusion agar as a test medium. When using the paper disc method, lower detection limit of T-3761 was approximately 0.05 microgram/ml and 0.1 microgram/ml for 1/15M phosphate buffer (pH 7.0) and human serum, respectively. T-3761 in human serum and urine was stable under freezing -20 degrees C for at least 28 days.

Polymeric N-acetyl-D-glucosamine (chitin) induces prostaglandin E2 in dogs

The level of prostaglandin E2 (PGE2) in the exudate induced by subcutaneous implantation of a complex formed from non-woven fabric of polyester (NWF) and polymeric N-acetyl-D-glucosamine (chitin) (chitin/NWF) or by implantation of NWF in dogs was measured by radioimmunoassay. The amount of PGE2 in the exudate induced by chitin/NWF was about five times as high as that in the exudate induced by NWF (p < 0.05), while the level of PGE2 in the exudate was similar to that in serum.

Biosynthesis of a biologically active single peptide chain containing the human common alpha and chorionic gonadotropin beta subunits in tandem

One of the distinguishing features of the gonadotropin and thyrotropin hormone family is their heterodimeric structure, consisting of a common alpha subunit and a hormone-specific beta subunit. Subunit assembly is vital to the function of these hormones: The conformation of the heterodimer is essential for controlling secretion, hormone-specific posttranslational modifications, and signal transduction. To address whether alpha and beta subunits can be synthesized as one chain and also maintain biological activity, a chimera composed of the human chorionic gonadotropin (hCG) beta subunit genetically fused to the alpha subunit was constructed. The resulting polypeptide hCG molecule not only was efficiently secreted but also displayed an increased biological activity in vitro and in vivo. These data show that the alpha and hCG beta subunits encoded as a single chain retain a biologically active conformation similar to that seen in the heterodimer. This approach can be used to investigate structure-function relationships of the glycoprotein hormone family that were previously not tractable because of the absolute dependence on assembly for the biological response. Moreover, other bioactive multisubunit ligands can be engineered where the combination efficiency and specificity of heterodimers and homodimers are otherwise difficult to control.

Sources of inhibin in early pregnancy

Inhibin is a glycoprotein which suppresses the release of follicle stimulating hormone (FSH) from the pituitary. Plasma immunoreactive inhibin levels during pregnancy have been reported to be higher than those during the normal menstrual cycle. In the present study, we investigated the cellular localization of inhibin alpha-, beta A-, and beta B-subunits in the human corpus luteum and placenta during early pregnancy. Luteal cells and theca luteal cells in the corpus luteum of pregnancy exhibited positive staining for all three inhibin subunits. We also observed positive staining with antisera against each inhibin subunit in the syncytiotrophoblast, but not in the cytotrophoblast, in the villi during early pregnancy. The staining with antisera against inhibin alpha- and beta A-subunits was clearly observed, whereas the staining for the beta B-subunit was faint. These results suggest that the gestational corpus luteum and the villous tissue may be major sources of inhibin during early pregnancy.

Immunohistochemical localization of inhibin alpha- and beta A-subunits in the ovary of immature female rats

Immunohistochemical localization of inhibin alpha- and beta A-subunits was examined in the ovaries of immature female rats. The granulosa cells in various sized ovarian follicles obtained from rats that were 10-24 days old exhibited positive staining for inhibin alpha- and beta A-subunits. The relative intensities of immunostaining for alpha- and beta A-subunits increased during follicular growth and maturation. Ova and internal thecal cells did not show any immunostaining for inhibin alpha- and/or beta A-subunits. These results suggest that granulosa cells of immature rat ovaries may produce inhibin from the 10th day after birth, and that an increase in the number of mature ovarian follicles results in an increase in inhibin production in the immature rat ovary during prepubertal development.

Increased platelet aggregability in patients with vertigo, sudden deafness and facial palsy

Many patients suffering from episodic vertigo have no cochlear symptoms. These patients have so far been diagnosed as having Meniere's disease of the vestibular type. However, the underlying mechanisms are still to be established. In the present study, we investigated platelet aggregability in patients with dizziness, Meniere's disease, sudden deafness and facial palsy, to examine whether abnormalities in platelet aggregation is one of the causes of episodic vertigo. In 36 patients with dizziness, in 13 with Meniere's disease, in 7 sudden deafness, and in 7 facial palsy, platelet aggregability to adenosine diphosphate (ADP) was assessed by optometric technique. It was found that platelet aggregability was increased in the patients with dizziness as well as with Meniere's disease, sudden deafness and facial palsy and only the two former patient groups showed a tendency of hyperlipidemia. The administration of antiplatelet and lipidemia drugs resulted in no recurrence of vertigo during at least 3 months' follow-up. Hence, the results of our study suggest that a possible initializing factor of vertigo without cochlear symptoms might be disturbed microcirculation due to platelet hyperaggregability.

Growth hormone induces expression of the c-fos gene on hypothalamic neuropeptide-Y and somatostatin neurons in hypophysectomized rats

The neuronal expression of the protooncogene c-fos may serve as a marker of neural activity. We previously examined brain sites upon which GH exerts an immediate early influence in rats and determined that the c-fos gene was transiently expressed in the hypothalamic periventricular nucleus (PeV) and arcuate nucleus (ARC) after recombinant human GH (rhGH) administration. As the distribution of c-fos messenger RNA (mRNA)-containing cells appeared to overlap with that of somatostatin (SS) neurons in both the PeV and ARC, we hypothesized that GH exerts a feedback effect on hypothalamic SS neurons. To extend this hypothesis, we characterized the neurons expressing the c-fos gene in response to rhGH administration in hypophysectomized rats. Adult male Wistar rats were hypophysectomized 10 days before use. After hypophysectomy, rats received daily sc injections of cortisone acetate (0.5 mg/kg BW) and L-T4 (20 micrograms/kg BW). Four international units (1.33 mg) of rhGH were given iv through an indwelling right atrial cannula. The vehicle was given to the control animals. Coronal sections of the hypothalamus were processed for in situ hybridization after rhGH or vehicle administration. To estimate the localization of neurons expressing the c-fos gene, the adjacent hypothalamic sections, 30 microns in thickness, were processed for hybridization histochemistry for SS, neuropeptide-Y (NPY), or GRF mRNA. In the ARC, the distribution of c-fos mRNA-containing cells appeared to overlap with that of NPY and partially with that of SS mRNA-containing cells, but it clearly differed from the distribution of GRF mRNA-containing cells. In the PeV, distribution of the cells expressing the c-fos gene was comparable to that of SS mRNA-containing cells. To further ascertain the distribution, hypothalamic sections, 6 microns in thickness, were processed by double label in situ hybridization using a 35S-labeled c-fos cRNA probe and a digoxigenin-labeled NPY or SS cRNA probe. In the ARC, 65% of the c-fos gene-expressing cells were NPY neurons. In the PeV, 60% of the c-fos gene-expressing cells were SS neurons. NPY is known to act within the hypothalamus and inhibit GH secretion via SS in rats, and the NPY neurons in the ARC have been shown to project to SS neurons in the PeV. Our findings suggest that the feedback effect of GH on the hypothalamus is mediated not only by SS neurons in the PeV, but also by NPY neurons in the ARC.