Highly Correlated Recurrence Prognosis in Patients with Metastatic Colorectal Cancer by Synergistic Consideration of Circulating Tumor Cells/Microemboli and Tumor Markers CEA/CA19-9

Circulation tumor cells (CTCs) play an important role in metastasis and highly correlate with cancer progression; thus, CTCs could be considered as a powerful diagnosis tool. Our previous studies showed that the number of CTCs could be utilized for recurrence prediction in colorectal cancer (CRC); however, the odds ratio was still lower than five. To improve prognosis in CRC patients, we analyzed CTC clusters/microemboli, CTC numbers, and carcinoembryonic antigen (CEA)/carbohydrate antigen 19-9 (CA19-9) levels using a self-assembled cell array (SACA) chip system for recurrence prediction. In CRC patients, the presence of CTC clusters/microemboli may have higher correlation in metastasis when compared to the high number of CTCs. Additionally, when both the number of CTCs and serum CEA levels are high, very high odds ratios of 24.4 and 17.1 are observed in patients at all stages and stage III of CRC, respectively. The high number of CTCs and CTC clusters/microemboli simultaneously suggests the high chance of relapse (odds ratio 8.4). Overall, the characteristic of CTC clusters/microemboli, CEA level, and CTC number have a clinical potential to enhance CRC prognosis.

Physical Cues in the Microenvironment Regulate Stemness-Dependent Homing of Breast Cancer Cells

Tissue-specific microenvironmental factors contribute to the targeting preferences of metastatic cancers. However, the physical attributes of the premetastatic microenvironment are not yet fully characterized. In this research, we develop a transwell-based alginate hydrogel (TAH) model to study how permeability, stiffness, and roughness of a hanging alginate hydrogel regulate breast cancer cell homing. In this model, a layer of physically characterized alginate hydrogel is formed at the bottom of a transwell insert, which is placed into a matching culture well with an adherent monolayer of breast cancer cells. We found that breast cancer cells dissociate from the monolayer and home to the TAH for continual growth. The process is facilitated by the presence of rich serum in the upper chamber, the increased stiffness of the gel, as well as its surface roughness. This model is able to support the homing ability of MCF-7 and MDA-MB-231 cells drifting across the vertical distance in the culture medium. Cells homing to the TAH display stemness phenotype morphologically and biochemically. Taken together, these findings suggest that permeability, stiffness, and roughness are important physical factors to regulate breast cancer homing to a premetastatic microenvironment.

Improving the diagnosis of LV non-compaction with cardiac magnetic resonance imaging

BACKGROUND

Current diagnostic criteria for left ventricular non-compaction (LVNC) poorly correlate with clinical outcomes. We aimed to develop a cardiac magnetic resonance (CMR) based semi-automated technique for quantification of non-compacted (NC) and compacted (C) masses and to ascertain their relationships to global and regional LV function.

METHODS

We analysed CMR data from 30 adults with isolated LVNC and 20 controls. NC and C masses were measured using relative signal intensities of myocardium and blood pool. Global and regional LVNC masses was calculated and correlated with both global and regional LV systolic function as well as occurrence of arrhythmia.

RESULTS

LVNC patients had significantly higher end-systolic (ES) and end-diastolic (ED) NC:C ratios compared to controls (ES 0.21 [SD 0.09] vs. 0.12 [SD 0.02], p<0.001; ED 0.39 [SD 0.08] vs. 0.26 [SD 0.05], p<0.001). NC:C ratios correlated inversely with global ejection fraction, with a stronger correlation in ES vs. ED (r=-0.58, p<0.001 vs. r=-0.30, p=0.03). ES basal, mid and apical NC:C ratios also showed a significant inverse correlation with global LV ejection fraction (ES basal r=-0.29, p=0.04; mid-ventricular r=-0.50, p<0.001 and apical r=-0.71, p<0.001). Upon ROC testing, an ES NC:C ratio of 0.16 had a sensitivity of 70% and a specificity of 95% for detection of significant LVNC. Patients with sustained ventricular tachycardia had a significantly higher ES NC:C ratio (0.31 [SD 0.18] vs. 0.20 [SD 0.06], p=0.02).

CONCLUSIONS

The NC:C ratio derived from relative signal intensities of myocardium and blood pool improves the ability to detect clinically relevant NC compared to previous CMR techniques.

Auditory efferent dysfunction in normal-hearing chronic idiopathic tinnitus

OBJECTIVE

To investigate the function of the auditory efferent system in patients with chronic idiopathic tinnitus, but normal pure-tone audiograms.

METHODS

We studied 15 subjects with normal hearing that had experienced either unilateral or bilateral persistent tinnitus for at least 3 months. The ears of the 15 subjects were classified into tinnitus-positive-ear (TPE) and tinnitus-negative-ear (TNE) groups. The control-ear group (CE) comprised the ears of 15 subjects with normal hearing and no tinnitus. We measured different types of otoacoustic emissions (OAEs), including spontaneous (SOAEs), transient evoked (TEOAEs), and distortion product (DPOAEs). We also analyzed contralateral suppression of OAEs and auditory brainstem responses (ABRs). Data were compared among TPE, TNE, and CE groups.

RESULTS

The data associated with cochlear mechanics, including the prevalence of SOAEs, the number of SOAE peaks, and the overall TEOAE responses in the absence of a contralateral stimulus, were not significantly different among the TPE, TNE, and CE groups. In the TPE group, contralateral stimuli failed to significantly suppress overall TEOAEs, and contralateral suppression of DPOAEs was significantly reduced over a limited frequency range. Furthermore, the TPE group showed prolonged latencies in waves III and V of ABRs.

CONCLUSION

This study demonstrated that abnormal contralateral suppression of OAEs and ABRs indicated a dysfunction in the ipsilateral efferent medial olivocochlear system; this might play a role in normal-hearing tinnitus.

Effects of tea drinking on auditory functions in aged subjects

The purpose of this study was to investigate the effects of Oolong tea drinking on the auditory functions in aged subjects. Retrospective cohort study was conducted on 265 subjects who were older than 55 years old. Tea drinking was determined from responses to a medical and food consumption questionnaires. The effects of Oolong tea drinking on pure tone thresholds (PTAs) for peripheral hearing and pitch pattern sequence (PPS) scores for central hearing were analyzed. Results showed that, before adjusting for other factors, PTAs were not significantly different between "non-tea drinkers" and "Oolong tea drinkes". But, the mean PPS score was higher in the "Oolong tea drinkers" (74.5 ± 12.7%) than in the "non-tea drinkers" (68.4 ± 13.9%). After adjusting for age, gender, waist circumference, and other variables, Oolong tea drinking (coefficient (β) ± standard error (SE) = 2.60 ± 0.67, P<0.001) was positively associated with PPS score, but not with PTAs, by multivariate linear regression analysis. In subgroup analysis for PPS score by gender, Oolong tea drinking showed a significant positive association with PPS score in males (β± SE=4.75 ± 0.95, P<0.001), but showed association of borderline significance with PPS score in females (β± SE=1.57 ± 0.94, P=0.097), with adjustment of other risk factors. In conclusion, Oolong tea drinking was associated with better central auditory function, but not with peripheral hearing thresholds, especially in male aged subjects.

Diagnostic value of combining bilateral electrocochleography results for unilateral Ménière's disease

We defined 'an interaural difference in the summating potential/action potential (SP/AP) ratio from the ipsilateral hearing-impaired side to the contralateral normal-hearing side of > or =0.15' as a positive result for a novel 'relative criterion' for the diagnosis of unilateral Ménière's disease. A uniform result could be derived only between a positive ECoG result and the side of disease in 78.7% subjects by conventional absolute criterion (SP/AP > or =0.42). By adding the relative criterion, we found that the diagnostic value increased greatly in specificity (91.2%) and increased slightly in positive predictive rate (79.2%), but decreased greatly in sensitivity (28.8%) and decreased slightly in negative predictive rate (52.5%). In addition, we verified which ear had the disease in all positive cases.

High molecular weight polyethylene nanospheres: synthesis, physical and mechanical properties--second harmonic generation

The weak second harmonic light generating from carbon nanotubes are detected. The signal intensity closely related to the density of pi-bonds attributed to the defects in the rolled graphene sheets, which is stimulated to have anharmonic oscillation as strongly affected by the environment. The intensities of SHG are diminished in order of well-aligned multi-wall carbon nanotubes (MWCNTs), randomly-aligned MWCNTs, and then to single-wall CNTs.

Inflammatory pseudotumor of the lung in a coal miner with pneumoconiosis

Inflammatory pseudotumors of the lung are uncommon and etiologically diverse lesions that often present as solitary masses in the lung. It may be difficult to distinguish these lesions from more commonly encountered lung neoplasms. Inflammatory pseudotumors can also occur in other organs, but the lung is most commonly involved. We describe a 63-year-old male coal miner with a 40-year history of dust exposure, who had a large right middle lobe mass on chest roentgenograms, with slow growth over the 7 years prior to admission. Repeated transthoracic echo-guided biopsies of the mass were indicative of an inflammatory and reactive process. The radiographic, histologic, and clinical findings indicated a diagnosis of inflammatory pseudotumor. The patient refused surgical intervention and was regularly followed at our outpatient clinic. Follow-up chest roentgenograms for 1 year revealed that the tumor size was stable. This case suggested that inflammatory pseudotumor, although uncommon, should be included in the differential diagnosis in a patient with pneumoconiosis and a solitary mass in the lung.

Vocal fold abnormalities in laryngeal tension-fatigue syndrome

This study sought to use videostrobolaryngoscopy to clarify possible biomechanical causes of dysphonia in patients with laryngeal tension-fatigue syndrome, a chronic functional dysphonia due to vocal abuse and misuse. The videostrobolaryngoscopic records of 301 laryngeal tension-fatigue syndrome patients were reviewed. The focus of observation was the visual characteristics of the mucus layer, vessel dilatation or neovascularization on the surface of vocal folds, abnormal glottal closure, and bilateral vibratory asymmetry. Abnormal findings on the vocal folds, especially during vibration, were noted in 270 cases (89.7%). Most patients (222, 73.8%) had multiple abnormalities. The results of this study suggest that chronic vocal overuse under excessive laryngeal muscle tension can cause phonotrauma and result in biomechanical property changes in the vocal fold's cover. These changes would hinder the regular vibration of the vocal folds, increase irregularities in voice signals, and worsen the symptoms of dysphonia.

Potentiation of noise-induced hearing loss by amikacin in guinea pigs

Noise and aminoglycosides initially attack cochlear outer hair cells (OHCs). Distortion product otoacoustic emissions (DPOAEs) are used for the early diagnosis of damage to OHCs. The effects of sub-damaging doses of amikacin, an aminoglycoside antibiotic agent, on noise-induced hearing loss (NIHL) were examined in guinea pigs. Animals were grouped by gender and exposed to broadband noise at 105 dB SPL for 12 h and/or injected i.m. with either amikacin (100 mg/kg/day) or saline for 10 days. Auditory brainstem response (ABR) thresholds, along with DPOAE amplitudes, were measured serially before and after noise exposure. DPOAE amplitudes decreased and ABR thresholds elevated immediately after noise exposure and then gradually recovered. At all frequencies, the emission amplitudes recovered completely to pre-exposure baseline values by 4 days after noise exposure. There was no effect of amikacin on either the ABR threshold or DPOAE amplitudes, in animals treated with amikacin only. However, amikacin significantly prolonged the effect of noise exposure on DPOAE amplitude but not on the noise-induced temporary threshold shift (TTS) of the ABR. In animals treated with a combination of noise and amikacin, significant changes in DPOAE amplitudes were still observed at 4 weeks after cessation of noise exposure. No gender difference in the responses to noise and/or amikacin could be demonstrated. The present findings indicate that even sub-damaging dosages of amikacin might impair recovery from NIHL in guinea pigs.

Inducing vocal register transition in an in vivo evoked phonation canine model

BACKGROUND AND PURPOSE

The nature of vocal registers is still a subject of controversy. The purpose of this study was to demonstrate the induction of timbre transition of vocal register in an in vivo evoked phonation canine model and thereby confirm vocal register transition as a laryngeal event.

MATERIALS

A canine midbrain stimulation evoked phonation model was used in this study. To repeat a low-pitched evoked phonation in the model, the low activity of the thyroarytenoid (TA) muscle and coordinate actions of other intrinsic laryngeal muscles were kept in a consistent condition by stimulating the same midbrain point with the same electric current intensity at the same timing in the respiratory cycle. The cricothyroid (CT) muscle was activated with an electrical current delivered directly to the muscle during the evoked phonation. Under constant subglottal pressure, CT muscle activity was varied while changes in vocal register of the evoked phonation were monitored.

RESULTS

The fundamental frequency (F0) of the evoked phonation increased as the stimulating current to the CT muscle increased. In addition to the increase in F0, data collected from six animals demonstrated that timbre register transition was induced by a stepwise increase of current to the CT muscle. The abrupt escalation of F0 and sudden change in sound quality, which could be verified perceptually, manifested the register transition. Frequency spectrum analysis showed that the sound in the modal register contained abundant harmonics that were different from those of the sound in the falsetto register, which contained fewer harmonics.

CONCLUSION

The results of this study indicated that intrinsic laryngeal muscles (especially CT and TA muscle interactions) regulate timbre-register transition in a canine model.

Na+,K+-ATPase and Ca2+-ATPase activities in the cochlear lateral wall following surgical induction of hydrops

Na+,K+-ATPase and Ca2+-ATPase activities have not been studied quantitatively in the cochlea affected by endolymphatic hydrops. The present study was designed to measure quantitatively the Na+,K+-ATPase and Ca2+-ATPase activities in the cochlear lateral wall and the threshold of auditory brainstem response (ABR) for guinea pigs in the early stages (=2 months) of experimentally induced endolymphatic hydrops. A significant negative association was demonstrated between Ca2+-ATPase activity and the change in ABR threshold for hydropic cochleae (P=0.014), but not for control cochleae (P=0.123), although no such significant association was revealed between Na+,K+-ATPase activity and any change in ABR threshold for both hydropic cochleae (P=0.751) and control cochleae (P=0.352). A significant increase in Ca2+-ATPase activity in the cochlear lateral wall was observed for the hydropic ear, in which normal ABR thresholds were maintained, as compared to the control ear. On the contrary, a mild decrease in Ca2+-ATPase activity in the cochlear lateral wall was observed for the hydropic ear, in which ABR thresholds increased significantly. The present findings suggest that alterations of Ca2+-ATPase activity in the cochlear lateral wall may implicate disturbed calcium-homeostasis in the inner ear, resulting in hearing dysfunction in the early stages of experimentally induced endolymphatic hydrops.

Abnormal auditory brainstem responses for mice treated with mercurial compounds: involvement of excessive nitric oxide

In this paper, we attempted to construct an animal (mouse) model for monitoring the oto-neurotoxicity of mercuric sulfide, comparing its toxicity with the well-known (organic) mercury compound methyl-mercury. Mice were treated with either mercuric sulfide (HgS, 0.1 and 1.0 g/kg per day) or methyl-mercury (MeHg, 0.2, 2.0 and 10 mg/kg per day) by gastric gavage for 7 consecutive days. Analysis of auditory brainstem response (ABR) indicated that significant elevation of the physiological hearing threshold as well as significant prolongation of interwave latency I-V was observed for MeHg -- (2.0 and 0.2 mg/kg per day) or HgS -- (1.0 g/kg per day, but not 0.1 g/kg per day) treated mice. Further, both MeHg- and HgS-treated animals demonstrated a significant prolongation of interwave latency I-V that increased with an increasing mean blood-Hg level. The oto-neurotoxicity of MeHg (2.0 mg/kg per day) persisted to at least 11 weeks subsequent to the cessation of its administration. The toxic effect of HgS, however, disappeared completely 5 weeks subsequent to the cessation of its administration. These results suggest a correlation between the Hg-elicited hearing dysfunction and the availability of mercury in brain tissue. Both inhibition of Na(+)/K(+)-ATPase activity and overproduction of nitric oxide in the brainstem are consistent with an analysis of the physiological hearing threshold and latencies of ABR waveform at all time points throughout the experimental process. Thus, it is proposed that high-dose HgS or MeHg intoxication is associated with a decrease in functional Na(+)/K(+)-ATPase activity in the brainstem of affected animals, this presumably arising via excessive nitric oxide production, and suggesting that brainstem damage may play a role in mercury-induced hearing loss.

Surgical treatment of tibial plateau fracture in elderly patients

This retrospective study involves 22 patients with displaced tibial plateau fractures who were treated surgically from July 1993 to April 1996. All the patients were over 60 years old (mean 66.3 years old, range 61-80 years). All of the patients were treated by open reduction and internal fixation with AO/ASIF buttress plates (Synthes, Bochum, Switzerland). Additional small fragment plate or inter-fragmental screws were used in some of them as indicated. Two patients died during follow-up of causes unrelated to the fractures. The average follow-up time was 49.8 months (range 36-68 months). The other 20 patients were interviewed at the outpatient clinic, and radiographs of bilateral standing knees were taken. By comparison with the uninjured side on radiographs, condylar joint space depression was noted in 6 patients. However, joint depression greater than 4 mm was not found. Malalignment with varus or valgus greater than 5 deg was not demonstrated in any case. Their range of motion was restored in all patients, with more than 120 deg of flexion and without extension lag except for the one who suffered a superficial wound infection. No complication required further surgical management. During the period of follow-up, no accelerated degenerative change in the operated knee joint resulted in total knee arthroplasty. Two patients needed occasional medical treatment for residual knee joint pain. Only two patients needed canes for assistance during walking due to old age and minor stroke. The results justify surgical treatment for displaced tibial plateau fractures in elderly patients.

The detrimental effects of potassium bromate and thioglycolate on auditory brainstem response of guinea pigs

Potassium bromate (KBrO3) is known to be an oxidizing agent that is used not only as a food additive, mainly in the bread-making process, but also as a neutralizer in thioglycolate containing hair curling set. Although it has been shown that bromate poisoning could cause severe and irreversible sensorineural hearing loss as well as renal failure, the action mechanism of bromate-induced otoneurotoxicity especially its combination with thioglycolate remains to be studied. In this study, we attempted to investigate the toxic effects of KBrO3 in combination with or without thioglycolate on the auditory brainstem response (ABR) system in the guinea-pigs which was claimed to be very susceptible to the xenobiotics. In a preliminary test, we have found that after consecutive 2 weeks administration, KBrO3 caused a significant prolongation of wave I-III and the interwave latencies of ABR as well as significantly elevated the threshold of hearing, suggesting that the conduction velocity of the peripheral auditory nerve was delayed. By contrast, the absolute latency of wave IV/V and the interwave latency of wave III-V were not significantly prolonged, suggesting that KBrO3 had no effect on the brainstem. This oto-neurotoxic effect of KBrO3 was markedly enhanced by combining with thioglycolate. Our data also indicated that KBrO3 combined with thioglycolate but not KBrO3 alone prominantly caused a decrease of body weight. However, enzymatic activities (including Na+/K+-ATPase and Ca2+-ATPase) and the level of nitric oxide (NO) was significantly affected in the brainstem. Based on these findings, we tentatively conclude that whether KBrO3 alone or KBrO3 combined with thioglycolate induced oto-neurotoxicity majorly through the peripheral auditory nerve rather than via the central brainstem intoxication.

Histological rearrangement in the facial nerve and central nuclei following immediate and delayed hypoglossal-facial nerve anastomosis

The timing of hypoglossal-facial nerve anastomosis is controversial. The present study was performed to clarify the influence of the timing of hypoglossal-facial nerve anastomosis on histological changes in the facial nerve and central nuclei using guinea pigs. The facial nerve was transected first at the labyrinthine portion, and then transected again at the stylomastoid foramen. Hypoglossal-facial nerve anastomosis was carried out immediately or 3 months later. Nerve regeneration and survival of the neurons in the facial and hypoglossal nuclei were evaluated by toluidine blue staining and horseradish peroxidase (HRP). Immediate anastomosis resulted in better nerve regeneration of the facial nerve, but the numbers of surviving neurons in the facial and hypoglossal nuclei were almost the same in both the immediate and delayed anastomosis groups.

Activities of Na(+),K(+)-ATPase and Ca(2+)-ATPase in cochlear lateral wall after acoustic trauma

Na(+),K(+)-ATPase and Ca(2+)-ATPase are well known participants in the active transport of ions in the inner ear. These two enzymes play an important role in maintaining cochlear function. Although changes in these enzymes' activities in the cochlea have been implicated in noise-induced hearing loss, no evidence of quantitative alteration of Na(+),K(+)-ATPase or Ca(2+)-ATPase activities has ever been shown. The present study was undertaken to determine the quantitative alterations of their activities by microcolorimetric assay in the cochlear lateral wall after acoustic trauma. Adult albino guinea pigs were exposed to white noise at 105+/-2 dB A for 10 min or 40 h. The age-matched control animals were not exposed to noise. Noise exposure resulted in a significant threshold shift of the auditory brainstem response (P<0.001). Significant decreases in activities of Na(+),K(+)-ATPase and Ca(2+)-ATPase were found in the cochlear lateral wall after noise exposure (P<0.001). Statistical analysis indicated that a good correlation held not only between the decline of these enzyme activities and noise-induced hearing loss, but also between the gradual partial recovery of these parameters during the first 10-day recovery period. The present findings suggest that metabolic damage and ionic disturbance may contribute, at least partially, to noise-induced hearing threshold shift.

Tone detection in Mandarin-speaking hearing-impaired subjects

The ability of native Mandarin-speaking, hearing-impaired subjects to detect Mandarin tones was assessed in this study. Nine subjects with mild sensorineural hearing loss (SNHL) and nine subjects with moderate SNHL participated in the study. Nine normal subjects served as control. All subjects received a tone detection test and Chinese word recognition test. The results show that tone detection was only minimally impaired in the mild SNHL group if audibility of the stimulus is well compensated for. In the moderate SNHL group, the mean score was significantly lower, but the difference was small. This suggests that tone detection is only slightly impaired for subjects with moderate hearing loss. For each individual tone, the mean scores for tones 2 and 3 were lowest and most easily confused by all normal and hearing-impaired subjects. No significant correlation was found between the tone detection score and word recognition score for all subjects. The relatively preserved ability to perceive tones in mild and moderate SNHL subjects may be helpful in their speech recognition.

Tuberculous pleurisy with effusion

To assess the clinical features of Taiwanese patients with tuberculous pleurisy and their response to treatment, we analyzed the records of patients treated for this condition from December 1990 through November 1995, at a regional 100-bed referral center for tuberculosis care. Diagnosis of tuberculous pleurisy was based on histologic evidence of caseating granulomatous inflammation in the pleural biopsy specimen, or evidence of mycobacteria in pleural fluid. Patients were also stratified on the basis of parenchymal involvement. Ninety-seven patients (79 men, 18 women) with a mean age of 47.5 (range, 15-90) years were included in the analysis. The two major symptoms were cough (69%) and shortness of breath (57%). Chest roentgenographs showed that the pleural effusion was unilateral in 88 (91%) patients, and small to moderate in amount in 74 (76%). Laboratory analysis of the pleural fluid showed moderate levels of glucose (4.6 mmol/L), with no significant difference between patients with and without parenchymal involvement. The levels of lactate dehydrogenase and triglycerides were significantly higher in patients with parenchymal involvement (172 vs 240.5 IU and 0.36 vs 0.45 mmol/L, respectively). In 85 of 93 patients (91%) with available data, lymphocytes were predominant in the differential count. All patients had received short-course chemotherapy for at least 6 months. After excluding the defaulters and patients receiving subsequent management in other hospitals, the overall rate of successful treatment was 97% (72/74). There was no significant difference in the treatment outcome between patients with parenchymal involvement and those without. None of the successfully treated patients had a relapse within a mean follow-up period of 31.7 +/- 18.4 months. We conclude that current patients with tuberculous pleurisy in Taiwan are not young, and short-course chemotherapy with isoniazid, ethambutol, rifampicin, and pyrazinamide is an effective treatment. The presence of parenchymal tuberculous lesions does not appear to influence the treatment outcome.

External ear resonance in patients with tympanic membrane perforations

This study investigated the effects of a tympanic membrane perforation on the external ear resonance. Measurements of external ear resonance using a probe-tube microphone system were performed in 14 patients who had medium to large unilateral tympanic membrane perforations. The contralateral normal ears of these 14 patients served as control. The results showed that there were no significant differences in the peak frequency, peak amplitude and peak sharpness between perforated and normal ears. However, intersubject variability in the resonant frequency was greater in the perforated group. In addition, the resonance curves of these two groups were substantially different. In 10 out of the 14 patients in the perforated group, the resonance curves showed 2-3 prominent peaks separated by valleys of about 10 dB reduced gain. In addition, in 11 out of 14 perforated ears, reduced responses (3.8 dB in average) occurred consistently in the lower frequency region (0.3-2 kHz). Clinically, the abnormal external ear resonance and the larger intersubject variation must be taken into consideration in fitting hearing aids for this group of patients.

Effect of acoustic trauma on cytochrome oxidase activity in stria vascularis

The present study was undertaken to determine the role of metabolic disturbance in noise-induced hearing loss by histochemical studies of cytochrome oxidase activity. Adult normal albino guinea pigs were used. The experimental animals were exposed to broad-band noise at 105 dB SPL for 24 h. The control animals were not exposed to the noise. The thresholds of the auditory brainstem response (ABR) of all guinea pigs were measured 3 times: before noise exposure, 1 day and 1 month later. The difference between the ABR thresholds before and after noise exposure was statistically significant. Vibratome sections of decalcified cochleae of the noise-exposed (n = 8) and control groups (n = 4) were incubated with Spector's medium and embedded with Epon. Thin sections (2 microm) and ultrathin sections (100 nm) were cut to observe cytochrome oxidase activity in the stria vascularis under light and electron microscopes, respectively. A decreased activity of cytochrome oxidase was consistently shown in the normal-appearing stria vascularis of most noise-exposed ears. Acoustic trauma has an adverse effect on cytochrome oxidase activity in the stria vascularis as well as on hearing. A decrease in the activity of cytochrome oxidase implicates that metabolic damage may play a role in noise-induced hearing loss.

Drug resistance patterns of tuberculosis in Taiwan

To evaluate the patterns of drug resistance of Mycobacterium tuberculosis in Taiwan, a total of 1,091 isolates collected from patients from January 1996 through December 1996 were tested for drug susceptibility using the absolute concentration method at the Taiwan Provincial Chronic Disease Control Bureau. The overall drug rate of resistance to at least one drug was 35.5%. Among the 249 isolates from patients who had never been treated for tuberculosis, 16.1% were resistant to one or more drugs; 1.6% were resistant to at least isoniazid and rifampin. Of 200 patients with prior antituberculosis treatment, 67.0% had isolates resistant to one or more drugs and 46.0% had isolates resistant to at least isoniazid and rifampin. We conclude that drug-resistant M. tuberculosis is an important issue in tuberculosis treatment in Taiwan, especially when dealing with patients with a prior history of antituberculosis treatment. More aggressive interventions, such as directly observed therapy, short-course, are needed to improve the cure rate of pulmonary tuberculosis and to decrease resistance rates.

Preliminary use of endoluminal ultrasonography in assessment of middle ear with effusion

Endoluminal ultrasonography with small-caliber and high-frequency transducer is suitable for transcanal assessment of middle ear with effusion. An endoluminal ultrasound transducer (size 6 French, 20 MHz) with a side-viewing scanning plane was used to image 12 ears of six children suspected of having effusion in the middle ear. Sonographic findings were compatible with those of operation in 10 diseased ears. One false-negative result was obtained, and one trial was aborted owing to trauma to the canal wall. The present study proves utility in demonstrating fluid behind the tympanic membrane. A promising use of endoluminal ultrasonography for middle ear evaluation might be expected if some modification could be made to the transducer.

Cultured human uterine smooth muscle cells are retinoid responsive

Primary cultures of human uterine smooth muscle cells have been widely used as a model system to evaluate agents that may play a role in the regulation of both normal and abnormal proliferative responses. We have used this in vitro system to determine if human uterine smooth muscle cells are responsive to treatment with a potent natural derivative of vitamin A, all-trans retinoic acid (ATRA). These studies were also designed to determine if there is a difference in retinoid responsiveness between normal smooth muscle and adjacent leiomyoma (a benign tumor of uterine smooth muscle). When cells were cultured in the presence of ATRA, a dose-dependent inhibition in proliferation was observed. This inhibition in proliferation was accompanied by an alteration in smooth muscle cell morphology. Both the inhibition in proliferation and the altered morphology were reversible when ATRA treatment was discontinued. Responsiveness to retinoids is determined, in part, by the expression of ligand-specific receptors belonging to the steroid/thyroid superfamily (RARs and RXRs); we have therefore identified the pattern of retinoid receptor transcript expression in human uterine smooth muscle cells. The data indicate that human uterine smooth muscle cells express retinoic acid receptors RAR alpha, beta, and gamma, and retinoid X receptors RXR alpha and beta. No difference in retinoid responsiveness or in the pattern of retinoid receptor expression was observed between normal smooth muscle and adjacent leiomyoma. This is the first observation of an antiproliferative effect of ATRA in uterine smooth muscle cells and the first report of retinoid receptor expression patterns in this cell type. Since retinoids are common pharmacologic tools in the treatment of a wide variety of hyperproliferative disorders, these observations may have both therapeutic and toxicologic implications.

Mondini dysplasia with recurrent meningitis

Mondini dysplasia is a congenital malformation of the inner ear, commonly associated with hearing impairment, cerebrospinal fluid otorrhea/rhinorrhea and recurrent meningitis. Two such cases are described, with hearing impairment, cerebrospinal fluid rhinorrhea, and several episodes of meningitis. Diagnosis was confirmed by high-resolution computed tomography. After surgical correction of the malformation, there was no recurrent episode of meningitis at subsequent follow-up. To avoid the suffering and the sequelae of recurrent meningitis, an early diagnosis and prompt surgical intervention are crucial for such patients.

Activities of carbonic anhydrase in the cochleae of guinea pigs with early experimental endolymphatic hydrops

Normal auditory function depends on maintenance of the unique ion composition in the endolymph. Carbonic anhydrase in the inner ear has been suggested to play an important role in maintaining the ion concentration and regulating fluids of the inner ear. Cochlear dysfunction may indicate changes in the biochemical components and osmotic pressure of the inner ear fluids as well as inadequate generation of intracellular metabolic energy. Dysfunction of the inner ear was investigated in the early stages of endolymphatic hydrops. Normal adult albino guinea pigs were operated on to obliterate the endolymphatic ducts and sacs of the right ears to induce endolymphatic hydrops. The auditory function of experimental guinea pigs was assessed according to the difference between the preoperative and postoperative hearing thresholds of the auditory brainstem response (ABR). Vibratome sections of the hydropic cochlea (right) and control cochlea (left) were stained histochemically for the activities of carbonic anhydrase in this study. Decreased activity of this enzyme was not shown consistently in the stria vascularis and organ of Corti of the hydropic cochlea in the early stage of endolymphatic hydrops whereas auditory dysfunction in the hydropic ear was noted from the ABR threshold for the experimental animals with 2 months survival. The results of the present study suggest that further investigation concerning the role of carbonic anhydrase in the cochlear auditory function is necessary.

Effects of tumor necrosis factor-alpha on glucose and albumin production in primary cultures of rat hepatocytes

Tumor necrosis factor-alpha (TNF) is known to alter significantly in vivo hepatic glucose and albumin metabolism. However, it remains unclear whether the observed effects represent direct actions of this factor or secondary responses due to the recruitment of other mediator systems. The present study was designed to investigate direct actions of TNF on glucose and albumin production in primary cultures of rat hepatocytes. Addition of TNF to the culture medium resulted in a 45% to 50% reduction in glucose production from a control level of 239 +/- 15 nmol/plate.h. This effect was reversed by addition of anti-TNF monoclonal antibody. In glycogen-depleted cells, short-term (5-hour) incubation with TNF did not affect hepatocyte albumin secretion, which was 8.13 +/- 0.29 microgram/plate.h. However, in cells exposed to insulin or in non-glycogen-depleted cells, addition of TNF resulted in a 10% to 25% reduction in albumin production. These findings indicate that TNF exerts direct inhibitory effects on hepatocyte glucose and albumin production, but the effects on the latter process are modest. A notable aspect of the findings is that the albumin effects are insulin or glucose substrate-dependent, which may have implications regarding liver function during nutritional support in critical illness.

Chronic mastoiditis mimicking recurrence of nasopharyngeal carcinoma: report of a case

A nasopharyngeal mass with cranial neuropathies usually indicates an advanced neoplastic process. We present a case of nasopharyngeal carcinoma diagnosed and treated 38 years ago. A nasopharyngeal mass recurred with cranial neuropathies and concurrent otologic infection in June, 1990. Repeated nasopharyngeal biopsies were negative with respect to tumors. Suspecting direct extension of the otologic infection, modified radical mastoidectomy was performed. The nasopharyngeal mass resolved after the surgical intervention. Spread of otologic infection from the temporal bone to the nasopharynx may be more common than was previously thought. Clinicians should modify diagnostic approaches in patients with a nasopharyngeal mass and concurrent otologic disease.

The high jugular bulb: report of five cases and a review of the literature

The jugular bulb varies widely in position and dimensions. A high jugular bulb is not an uncommon finding in temporal bones. Besides our five cases with different clinical manifestations, we review 52 cases diagnosed clinically and published previously in the English literature. The high jugular bulb occurs more often on the right temporal bone. Certain pathologic conditions, such as an abnormal bone formation, an aberrant sinusojugular system, or decreased pneumatization of the mastoid bone, may predispose an individual to its occurrence. Most people with this anatomical variation remain asymptomatic. However, various otologic problems and symptoms may be attributed to this condition. A high resolution computed tomography scan is the most convenient diagnostic tool at present. Law projection plain mastoid radiography may reveal a high jugular bulb in certain cases, providing a preoperative warning to an otologic surgeon. An exploratory tympanotomy is not suggested for those with a high jugular bulb with a conductive hearing loss, while jugular vein ligation has been reported to have good results in alleviating intractable pulsatile tinnitus. For most asymptomatic patients, regular long-term follow-up is recommended.

Reduced Na(+)-K(+)-ATPase activities in the cochleae of guinea pigs with experimental endolymphatic hydrops

Normal auditory function depends on the maintenance of the unique ion composition in the endolymph. The Na(+)-K(+)-ATPase in the lateral wall of the cochlear duct has been suggested to play an important role in maintaining the endolymphatic ion concentration and in generating a positive endocochlear potential. Cochlear dysfunction may indicate changes in the biochemical components and osmotic pressure of the inner ear fluids as well as inadequate generation of intracellular metabolic energy. Dysfunction of the stria vascularis and spiral prominence was investigated in the early stages of endolymphatic hydrops. Vibratome sections of hydropic and normal cochleae were stained histochemically for Na(+)-K(+)-ATPase activity in this study. Decreased activity of this enzyme was shown in the stria vascularis and spiral prominence of the hydropic cochlea in the early stage of endolymphatic hydrops. The results coincide with those of studies of electrophysiologic changes in cochlear function in hydropic animals by others. The results of the present study provide further information concerning a possible deficit in ion transport activity and decreased enzymatic activity in the cochlea.

Factors affecting secretory protein production in primary cultures of rat hepatocytes

Previous studies suggest that protein synthesis in the liver may be influenced by alterations in hepatic proteolysis and gluconeogenesis. Since proteolysis and gluconeogenesis are accelerated in acute stress states (especially when associated with nutrient deprivation), these alterations may substantially affect hepatic protein synthesis, the integrity of which is important for host survival. In the present study, we have investigated albumin secretion and glucose production in primary cultures of rat hepatocytes in response to nutrient-limiting conditions, including amino acid depletion, proteolysis inhibition, and augmented gluconeogenesis. In nonlimiting nutrient culture medium containing 10 times the normal plasma amino acid concentrations, hepatocytes produced 8.05 +/- 1.62 micrograms/plate-hr of albumin. Short-term (5 hr) inhibition of cellular protein degradation with the lysosomal protease inhibitor leupeptin did not influence albumin production, but caused a profound reduction (17-41%) when amino acid supply was reduced to the physiologic range (1.5-0.5 times, respectively). This indicates the need for active proteolysis for the maintenance of secretory protein production during nutrient limitation. Similarly, leupeptin inhibited glucose production by 22-30% at physiologic (1.5 times and 0.5 times, respectively) amino acid concentrations. Additionally, hepatocyte glucose production could be augmented 168% by epinephrine (2 microM) in 10 times medium, but this response was markedly depressed by leupeptin. Similar catecholamine-mediated effects, but of a smaller magnitude, were noted at lower medium amino acid concentrations. These findings indicate that hepatocyte albumin and glucose production are associated with the common factor of active cellular proteolysis, probably through the regulation of amino acid supply. However, protein synthesis exhibits a higher priority, since stimulated hepatocyte glucose production did not substantially alter albumin secretion.

Effects of insulin on total RNA, poly(A)+ RNA, and mRNA in primary cultures of rat hepatocytes

The purpose of this study was to examine mechanisms involved in the regulation of protein synthesis in primary cultures of rat hepatocytes. Hepatocytes were maintained in a chemically defined serum-free medium in the presence or absence of insulin. The rate of protein synthesis in hepatocytes deprived of insulin between days 2 and 5 of culture was reduced to 67% of the rate observed in insulin-maintained controls. The decrease in protein synthetic rate was accompanied by a proportional fall in the content of both total RNA and poly(A)+RNA, suggesting that the capacity for protein synthesis was reduced in the absence of insulin. Both total RNA and poly(A)+ RNA contents and the protein synthetic rate were returned to control values after 3 days of insulin resupplementation. In addition, the effect of insulin on the expression of specific mRNAs was assessed by in vitro translation of total RNA followed by two-dimensional gel analysis of radiolabeled translation products. Only 13 of the greater than 150 spots discernible on the two-dimensional gels were altered in response to insulin. The mRNAs that were altered include examples of repression and stimulation of expression in response to insulin deprivation. Thus, in isolated rat hepatocytes, insulin regulates the capacity of both overall protein synthesis as well as the capacity for the synthesis of specific proteins.

Changes in activity of cytochrome oxidase in the cochleae of guinea pigs with experimental endolymphatic hydrops

Cochlear dysfunction may indicate inadequate generation of intracellular metabolic energy which is necessary for the regulation of the transport of ions and fluid as well as production of electro-energy in the cochlea. Changes in cochlear function in the early stages of endolymphatic hydrops attributed to dysfunction of the sensory hair cells and stria vascularis were investigated. The main source of metabolic energy, produced by intracellular respiration, is located in the stria vascularis and sensory hair cells. Since cytochrome oxidase is one of the most important respiratory enzymes, vibratome sections of hydropic and normal cochleae were stained cytochemically for cytochrome oxidase activity in this study. Decreased activity of this enzyme was consistently shown in the normal-appearing outer hair cells and stria vascularis, as well as the degenerated hair cells and stria vascularis, of the higher turns of the hydropic cochlea. The results coincide with those in other studies of electrophysiologic changes in cochlear function in hydropic animals. A decrease in the activity of respiratory enzymes was noted before the destruction of the cellular structures. The activity of cytochrome oxidase may serve as a useful indicator for demonstrating the functional status of cochlear hair cells and stria vascularis.

Nuclear calcium gradients in cultured rat hepatocytes

Ca2+ concentrations ([Ca2+]) in cytosol and nucleus in fura-2-loaded cultured rat hepatocytes were determined by three-dimensional (3-D) optical-sectioning microscopy. After determining the empirical 3-D point spread function of the fluorescence microscope-coupled digital video imaging system, contaminating light arising from optical planes above and below the plane of interest was removed by deconvolution using the nearest-neighboring approach (NNA) algorithm. Although deconvolution resulted in substantial improvement in accuracy of fluorescence intensity determinations in single-wavelength excitation images as well as sharper delineation of boundaries between cellular compartments, the complicated mathematical process did not significantly enhance the precision of [Ca2+] values derived from ratiometric (ratio of dual-wavelength excitation) images. In resting hepatocytes, cytosolic Ca2+ (210 +/- 15 nM) was 1.6- to 2-fold higher than nuclear Ca2+ (128 +/- 12 nM). This difference in Ca2+ between the two compartments was detected both in raw ratiometric images and in those processed with NNA algorithm. Addition of arginine vasopressin or epidermal growth factor resulted in significant increases (2- to 3-fold) in both cytosolic and nuclear Ca2+; however, the nuclear-to-cytosolic Ca2+ gradient was preserved in hepatocytes stimulated with mitogens. We conclude that the hepatocyte nuclear membrane contains Ca2+ permeability barriers and Ca2+ transport mechanisms that may be hormonally sensitive. We postulate that the increase in nuclear Ca2+ may be important in regulation of cell proliferation induced by mitogens, possibly by activating Ca(2+)-dependent endonucleases, nuclear calmodulin, or nuclear protein kinase C.

Ultrastructural study of cytochemical localization of carbonic anhydrase in the inner ear

Vibratome sections were stained for cytochemical localization of carbonic anhydrase (CA) activity in vestibular neuro-epithelium, spiral ligament and spiral limbus. The new finding is the localization of reaction products in the interdental cells of the spiral limbus, Claudius' cells, mesothelial cells of the lower border of spiral ligament, vestibular sensory cells and perilymphatic cells, which have not earlier been proved to have CA activity. The interdental cells showed the products only on the basolateral infoldings. Claudius' cells showed prominent products in the microvilli. In the vestibular sensory cells, the products were present only in the stereocilia and cuticular areas. The perilymphatic fibrocytes under the vestibular sensory epithelium, like the fibrocytes of the spiral ligament, revealed diffuse products throughout the whole cell. In the vestibular supporting cells and transitional cells, the reaction products were localized diffusely in the cytosol, but not in the secretory granules. In the long cell projections of the transitional cells, type II fibrocytes at spiral prominence, mesothelial cells at the uppermost region of the spiral ligament and Borghesan's zone, the localization of the reaction products was the same as that of the basolateral infoldings of the vestibular dark cells and marginal cells of stria vascularis shown previously.

Gonadotropins increase concentrations of immunoreactive insulin-like growth factor-I in porcine follicular fluid in vivo

To evaluate the regulation of ovarian insulin-like growth factor-I (IGF-I) during follicular growth in vivo, we measured the concentration of this peptide in follicular fluid (FFL) of immature gilts during the induction of follicular development by pregnant mare's serum gonadotropin (PMSG) and human chorionic gonadotropin (hCG). FFL concentrations of immunoreactive (i) IGF-I were compared with those of intrafollicular steroids and with concentrations of iIGF-I, estradiol (E2), and porcine growth hormone (GH) in serum. PMSG, administered at Time 0, induced a significant (p less than 0.01), time-dependent increase in intrafollicular iIGF-I that peaked 72 h after administration of the hormone, before the administration of hCG. During the first 72 h, the changes in ovarian iIGF-I paralleled those for progesterone and E2. After the administration of hCG at 72 h, FFL levels of E2 fell, those of iIGF-I remained constant, and progesterone rose. Serum E2 concentrations paralleled those in FFL. Since serum GH and IGF-I levels rise during spontaneous puberty in some species, these levels were also monitored. However, a significant treatment effect on serum GH and iIGF-I was not demonstrated. In summary, ovarian concentrations of iIGF-I are increased by gonadotropic hormones in vivo. The absence of concomitant changes in circulating levels of iIGF-I and GH suggests that the gonadotropin effects are exerted directly on the ovary. These results, together with more abundant data regarding secretion and action of IGF-I in cultured granulosa cells, suggest that IGF-I may function in an autocrine or paracrine fashion to amplify the actions of gonadotropins at an ovarian level.

Concomitant effects of growth hormone on secretion of insulin-like growth factor I and progesterone by cultured porcine granulosa cells

The observation that GH deficiency delays the onset of puberty has raised the question of the effect of GH on gonadal development. In addition, recent studies in the rat have indicated that GH is able to elevate ovarian levels of immunoreactive insulin-like growth factor I (iIGF-I) in vivo and enhance FSH-induced granulosa cell differentiation in vitro. To evaluate further the possibility of direct effects of GH on ovarian function, we have studied the action of GH on the secretion of iIGF-I and progesterone by cultured porcine granulosa cells from immature follicles. The effects of GH were compared with those of estradiol (E2) and FSH, hormones previously shown to stimulate steroidogenesis and iIGF-I production in this system. GH-stimulated cultures secreted 7.8 times as much iIGF-I per cell as control cultures, while cultures treated with E2 plus FSH secreted 4.5 times as much, and the combination of all three hormones produced an additional increment. The GH-dependent immunoreactivity was localized to two peaks on gel filtration which coeluted with authentic IGF-I and with an IGF-binding protein. In contrast to the results with iIGF-I secretion, GH was a relatively ineffective stimulator of progesterone secretion, resulting in levels 2.6 times the control value, compared to levels 7.4-fold the control value in cultures treated with E2 plus FSH. However, when the three agonists were combined, a synergistic interaction was observed which resulted in progesterone values 33.3 times the control value. In parallel studies, PRL was unable to mimic the effects of GH on iIGF-I or progesterone secretion. In summary, GH has direct stimulatory actions on porcine granulosa cells. Compared to E2 and FSH, established stimulators of these cells, GH is at least comparable in effectiveness with regard to iIGF-I secretion, but less effective as a stimulator of steroidogenesis. However, GH dramatically enhances the effects of E2 and FSH on progesterone secretion. These effects of GH could be important during the onset of puberty, when GH levels in plasma are elevated.

Ovarian epidermal growth factor-like activity. Concentrations in porcine follicular fluid during follicular enlargement

Numerous data indicate that epidermal growth factor has important effects on cultured granulosa cells. However, most of the few attempts to detect epidermal growth factor in ovarian tissue have been unrevealing. In this study, ovarian epidermal growth factor-like activity was easily detected by a radioreceptor assay based on the A431 cell line but not by an immunoassay for mouse epidermal growth factor. The concentration of this activity in follicular fluid from small porcine ovarian follicles was higher than that in fluid from medium or large follicles or serum (p less than 0.01), but lower than that in salivary gland extracts. Receptor-active epidermal growth factor-like peptides could function as local ovarian regulators.

Gonadotropins and estradiol stimulate immunoreactive insulin-like growth factor-I production by porcine granulosa cells in vitro

Previous studies have established the ovarian granulosa cell as a site of insulin-like growth factor-I (IGF-I) secretion and action, suggesting an autocrine function for this peptide in the ovary. To better understand how this putative autocrine system is regulated and its interface with the classic ovarian trophic hormones FSH, LH, and estradiol (E2), we have studied the effects of these hormones on the secretion of immunoreactive IGF-I (iIGF-I) by cultured porcine granulosa cells. Immature granulosa cells were cultured under serum-free conditions which were optimized to allow maximal iIGF-I production and hormonal responsivity. Measurements of iIGF-I were made after minimizing the influence of IGF-binding proteins by either acid gel filtration or reverse phase chromatography. Since the two preparative procedures gave roughly comparable results, the more expeditious reverse phase procedure was chosen for most samples. Cycloheximide virtually eliminated measurable iIGF-I in culture, suggesting that the peptide measured was newly synthesized, and degradation of IGF-I by cultured granulosa cells was negligible. Consequently, the medium levels provided an accurate indication of cellular secretion over the collection period. Under optimal culture conditions, iIGF-I was readily measurable and responsive to treatment with ovarian trophic hormones. The iIGF-I levels in several experiments with these hormones were as follows: FSH treatment, 1.58 +/- 0.21 times the control value (n = 5 experiments); E2 treatment, 1.26 +/- 0.12 times the control value (n = 5); E2 plus FSH, 3.12 X 0.31 times the control value (n = 8); LH, 1.33 +/- 0.12 times the control value (n = 3); LH plus FSH, 1.78 +/- 0.2 times the control value (n = 1). To assess the role of cAMP in the mediation of gonadotropin effects in this system, granulosa cells were treated with a phosphodiesterase inhibitor (methylisobutylxanthine), which resulted in iIGF-I levels 1.61 +/- 0.7 times the control level. In the presence of FSH, a further stimulatory effect was demonstrated (3.76 +/- 0.29 times control). In addition, the cAMP analog 8-bromo-cAMP dramatically increased iIGF-I levels (6.3 +/- 0.72 times control). These data provide the first demonstration that gonadal iIGF-I secretion can be stimulated by the principal hormones involved in trophic regulation of the ovary. As with other gonadotropin-dependent functions of granulosa cells, this effect appears to be mediated by cAMP and enhanced by E2. This interface between circulating hormones and autocrine systems could provide an important mechanism to amplify the effects of gonadotropic hormones on a local level.

Polyamines and autocrine control of tumor growth by prolactin in experimental breast cancer in culture

We have previously observed that both polyamines and an autocrine mechanism are involved in the stimulation by ovine PRL (oPRL) of growth of the N-nitrosomethylurea-induced rat mammary tumor cultured in vitro in the soft agar clonogenic assay. These experiments were designed to test the interaction between these two pathways of oPRL action in this system. In agreement with previous findings in our laboratory, conditioned medium obtained from oPRL-treated (oPRL-CM), but not untreated, tumors consistently stimulated colony formation when added to N-nitrosomethylurea mammary tumors plated in soft agar under serum-free medium conditions. Administration of alpha-difluoromethyl-ornithine (DFMO), an irreversible inhibitor of polyamine biosynthesis, abolished the colony-stimulating effect of oPRL-CM. The inhibitory effect of DFMO was reversed in a dose-dependent fashion by the addition of spermidine, which entirely restored the growth-promoting action of oPRL-CM. In addition, the administration of increasing amounts of spermidine potentiated the colony-stimulating effect of suboptimal concentrations of oPRL-CM. In contrast, manipulation of the polyamine environment with DFMO and/or spermidine administration did not affect the number of colonies formed when conditioned medium from untreated tumors was added instead of oPRL-CM. We conclude that the polyamine pathways plays an essential role in the expression of autocrine control of tumor growth by oPRL.

Relaxin affects the shape of rat myometrial cells in culture

The shape of rat myometrial cells in culture was altered by exposure to hormones. Oxytocin (107 microU/ml) significantly decreased mean cell length and area. Treatment of oxytocin-treated cells with relaxin (1.5 micrograms/ml), isoproterenol (10 microM) or (Bu)2 cAMP (1 mM) for 15 min resulted in a significant increase in cell length and area. The effect of relaxin was time dependent, with a significant increase in cell length by 1 min and in cell area by 3 min. Relaxin elicited a concentration-dependent increase in cell length and area between 0.1 and 2 micrograms/ml. The actions of relaxin correlate in time course and concentration dependence with its effects on cAMP elevation in the presence of 0.4 microM forskolin and on changes in myosin light chain kinase kinetic parameters in these cells. Myometrial cells in culture constitute a useful model system in which to correlate physical and biochemical effects of relaxin and other hormones.

Relaxin treatment alters the kinetic properties of myosin light chain kinase activity in rat myometrial cells in culture

Relaxin treatment altered the kinetic properties of rat myometrial cell myosin light chain kinase (MLCK) by increasing the K50 of the enzyme for calmodulin (CaM) from 1.1 +/- 0.1 to 38 +/- 14 nM. When MLCK was assayed in the presence of 7 nM CaM to maximize the effect of the decreased affinity for CaM between control and relaxin-treated groups, a rapid concentration-dependent effect of the hormone was observed. Relaxin decreased MLCK activity significantly within 1 min. The ED50 of the effect was 0.4 microgram/ml. In addition to its effect on Ca2+-CaM-dependent activity, relaxin also decreased Ca2+-CaM-independent MLCK activity. This decrease was not attributable to a decrease in the affinity of the enzyme for myosin. There was a temporal association between the effects of relaxin on mean cell length, elevation of cAMP levels in the presence of 0.4 microM forskolin previously shown in other studies, and the alteration of MLCK activity. All three parameters were changed significantly within 1 min after exposure to relaxin. The ED50 of relaxin for cell shape changes, cAMP elevation, and effects on MLCK activity were all approximately 0.4 microgram/ml. Relaxin may act in part by a cAMP-mediated phosphorylation of MLCK, thereby decreasing its affinity for CaM. The effect on MLCK may be linked to a decrease in the phosphorylation of myosin light chains and the promotion of uterine relaxation.

The effect of relaxin on cyclic adenosine 3',5'-monophosphate concentrations in rat myometrial cells in culture

Relaxin, a uterine relaxant secreted by the corpus luteum, was able to elevate cAMP concentrations in the presence of 1-methyl-3-isobutyl xanthine (MIX) (0.1 mM) or forskolin (0.4 microM) in a time- and dose-dependent manner in rat myometrial cells in culture but not in stromal cells. The optimal culture conditions for the cAMP response were determined to be an initial plating density of 1-1.5 X 10(6) cells/ml (3 ml/35-mm dish) and a 2-day culture period. In the presence of MIX, the time course of cAMP elevation in response to relaxin exhibited a lag phase of more than 5 min before cAMP concentrations rose significantly. However, in the presence of forskolin, relaxin elevated cAMP within 1 min. The concentration-response relationships were almost identical in the presence of MIX or forskolin. Isoproterenol was able to increase cAMP concentrations in myometrial cultures in both the absence and presence of MIX and to elevate cAMP levels rapidly within 1 min. These data suggest that cAMP could play some role in the initiation of uterine relaxation mediated by relaxin.