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PubMed1990

Septopremaxillary ligament resection and midfacial growth in a chimpanzee animal model.

Data collected from human studies suggests a relationship between a disruption of the septopremaxillary ligament (SPL) attachment and midfacial hypoplasia in complete cleft individuals. The present study investigates the SPL-traction mechanism and midfacial growth in a chimpanzee animal model. Seventeen chimps (7 unoperated controls, 5 shams, and 5 animals with early SPL reaction) were used in the present study. Lateral head x-rays and dental study models were collected quarterly through 1200 days of age. Growth rates (slopes of the linear growth components) were statistically compared across groups. Premaxillary growth rates were significantly (p less than 0.001) reduced in SPL resected animals compared to the other groups. Maxillary growth rates were significantly reduced in both SPL and sham animals compared to unoperated controls. No significant differences were noted for midfacial height. We conclude that SPL resection produced a significant effect on anterior midfacial growth independent of surgical trauma. These data support the concept of early reestablishment of the SPL in primary nasolabial cleft repair.

Animals↗
PubMed1998

The effects of broadband noise masking on cortical event-related potentials to speech sounds /ba/ and /da/.

OBJECTIVE: To systematically investigate in normal-hearing listeners the effects of decreased audibility produced by broadband noise masking on the cortical event-related potentials (ERPs) N1, N2, and P3 to the speech sounds /ba/ and /da/. DESIGN: Ten normal-hearing adult listeners actively (button-press response) discriminated the speech sounds /ba/ and /da/ presented in quiet (no masking) or with broadband masking noise (BBN), using an ERP oddball paradigm. The BBN was presented at 50, 60, and 70 dB SPL when speech sounds were presented at 65 dB ppe SPL and at 60, 70 and, 80 dB SPL when speech sounds were presented at 80 dB ppe SPL. RESULTS: On average, the 50, 60, 70, and 80 dB SPL BBN maskers produced behavioral threshold elevations of 18, 25, 35, and 48 dB (average for 250 to 4000 Hz), respectively. The BBN maskers produced significant decreases (relative to quiet condition) in ERP amplitudes and behavioral discriminability. These decreases did not occur, however, until the noise masker intensity (in dB SPL) was equal to or greater than the speech stimulus intensity (in dB ppe SPL), that is, until speech to noise ratios (SNRs) were < or = 0 dB. N1 remained present even after N2, P3, and behavioral discriminability were absent. In contrast to amplitudes, ERP and behavioral latencies showed significant decreases at higher (better) SNRs. Significant latency increases occurred when the noise maskers were within 10 to 20 dB of the stimuli (i.e., SNR < or = 20 dB). The effects of masking were greater for responses to /da/ compared with /ba/. Latency increases occurred with less masking for N1 than for P3 or behavioral reaction time, with N2 falling in between. CONCLUSIONS: These results indicate that decreased audibility as a result of masking affects the various ERP peaks in a differential manner and that latencies are more sensitive indicators of these masking effects than are amplitudes.

Adult↗
PubMed2002

Speech recognition performance of patients with sensorineural hearing loss under unaided and aided conditions using linear and compression hearing AIDS.

OBJECTIVES: This study compared speech recognition performance on the Northwestern University Auditory Test No. 6 (NU-6) and the Connected Speech Test (CST) for three hearing aid circuits (peak clipping [PC], compression limiting [CL], and wide dynamic range compression [WDRC]) in adults with symmetrical sensorineural hearing loss. The study also questioned whether or not hearing aid benefit for the three circuits was dependent upon the speech level and the signal-to-babble ratio (S/B) and upon the degree and slope of hearing loss. DESIGN: Unaided speech recognition performance for NU-6 and CST materials presented from a loudspeaker at 0 degrees was measured during Visit 1, and both unaided and aided performance was measured at 3-mo intervals during Visits 2 to 4. The NU-6 was presented in quiet at a conversational speech level of 62 dB SPL. The CST was presented in 10 listening conditions-three S/B (-3, 0, and 3 dB) at each of three speech levels (soft speech at 52 dB SPL, conversational speech at 62 dB SPL, and loud speech at 74 dB SPL) and in quiet at 74 dB SPL. Uncorrelated multi-talker babble was presented from two loudspeakers at 45 degrees on each side of the main speaker. Hearing aid benefit was examined for 360 subjects divided into four groups of hearing loss, pure tone average <40 dB HL and slope <10 dB/octave or >10 dB/octave and hearing loss >40 dB HL for the two slope categories. RESULTS: Hearing aid benefit (aided minus unaided performance) measured on the NU-6 in quiet exceeded 31 rau for all three circuits. Although small statistical advantages were found for the WDRC, the differences were approximately 2% and are not considered clinically relevant. Unaided CST performance showed a complex relationship between presentation level and signal-to-babble ratio that was further confounded by the degree of hearing loss. For the two mild hearing loss groups and for each of the three nominal signal-to-babble ratios, CST performance decreased by 20 rau for the -3 dB S/B to 6 rau for the 3 dB S/B as speech level increased from 52 to 74 dB SPL. In contrast, unaided performance increased by 32 to 13 rau with signal level for all signal-to-babble ratios for the two >40 dB hearing loss groups. Overall, aided CST performance exceeded unaided performance for all 10 conditions. As expected, hearing aid benefit was greatest (27 rau) for soft speech and smallest for loud speech (6 rau). Differences among the hearing aid circuits were small with only one significant difference; the WDRC at 62/0 was poorer by 3 rau than the other two circuits. When the CST data were analyzed as a function of hearing loss, five pair-wise comparisons were significant. In contrast to the unaided performance, aided performance for all hearing loss groups decreased as presentation level increased, even though the signal-to-babble ratio was constant. CONCLUSIONS: All three hearing aids circuits provided benefit over the unaided condition in both quiet and noise. The greatest benefit was measured for soft speech in the more severe hearing loss groups. Although only small differences were measured among the three hearing aid circuits, significant differences favored the PC and CL circuits over the WDRC in the mild hearing loss groups and favored the WDRC over the PC in the more severe, sloping hearing loss group. An interesting interaction between speech level, signal-to-babble ratio, degree of hearing loss, and amplification was found. For a constant signal-to-babble ratio, recognition performance decreased as speech level increased from 52 to 74 dB SPL. The effect was most marked in the milder hearing loss groups and in the aided conditions, and occurred at even the lowest speech levels.

Adult↗
PubMed1991

The startle eyeblink response to low intensity acoustic stimuli.

Four experiments were conducted to investigate the acoustic startle response to stimuli of low intensities. Eyeblink responses (integrated EMG from orbicularis oculi) were measured from male and female college students. Experiment 1 compared tone and noise stimuli varying in intensity (50 and 60 dB(A) SPL), with noise stimuli producing greater response amplitude and probability than tone stimuli. Experiment 2 was designed to investigate temporal summation of low intensity stimuli using single and paired 70dB(A) SPL broadband noises, and an onset-to-onset interval between the brief stimuli in a pair equal to the duration of the single stimuli. Increasing the duration of single stimuli resulted in larger responses, illustrating temporal summation. Experiment 3 used 60 and 70 dB(A) SPL broadband noise varying in rise/fall time, with faster-rising stimuli producing larger responses, and more intense stimuli producing larger and more probable responding. Experiment 4 employed the startle modification paradigm using 60 and 70 dB(A) SPL broadband noises as startle stimuli and a 50dB(A) SPL tone as a prepulse. Response amplitude and probability to both 60 and 70 dB(A) SPL stimuli were significantly inhibited by the 50dB(A) SPL prepulse. These studies show that the acoustic startle response is more sensitive than previously thought, and the elicitation of startle by low intensity stimuli argues against the limitation of the startle reflex as a high intensity phenomenon. These findings can increase the application of this response system by showing that startle stimuli need not be of high intensity, because reliable and differential startle can be elicited and modified at relatively low stimulus intensities.

Adolescent↗
PubMed1997

A chimeric enhancer-of-split transcriptional activator drives neural development and achaete-scute expression.

Drosophila melanogaster neurogenesis requires the opposing activities of two sets of basic helix-loop-helix (bHLH) proteins: proneural proteins, which confer on cells the ability to become neural precursors, and the Enhancer-of-split [E(spl)] proteins, which restrict such potential as part of the lateral inhibition process. Here, we test if E(spl) proteins function as promoter-bound repressors by examining the effects on neurogenesis of an E(spl) derivative containing a heterologous transcriptional activation domain [E(spl) m7Act (m7Act)]. In contrast to the wild-type E(spl) proteins, m7Act efficiently induces neural development, indicating that it binds to and activates target genes normally repressed by E(spl). Mutations in the basic domain disrupt m7Act activity, suggesting that its effects are mediated through direct DNA binding. m7Act causes ectopic transcription of the proneural achaete and scute genes. Our results support a model in which E(spl) proteins normally regulate neurogenesis by direct repression of genes at the top of the neural determination pathway.

Animals↗
PubMed1990

Cardiopulmonary sympathetic afferent excitation of lower thoracic spinoreticular and spinothalamic neurons.

1. Responses of spinoreticular (SRT) and spinothalamic (STT) neurons located in the T7-T9 segments to cardiopulmonary sympathetic afferent (CPS) stimuli were studied in 27 cats that were anesthetized with alpha-chloralose. 2. CPS stimulation excited 32 SRT and 10 STT neurons. Each neuron was also excited by stimulation of the left greater splanchnic nerve (SPL) and had a somatic receptive field that was most commonly located on the upper abdomen and over the lower rib cage. An additional 12 SRT and 3 STT neurons received input from SPL and somatic structures but failed to respond to CPS stimulation. 3. CPS stimulation evoked early responses (23 cells) or both early and late responses (19 cells) that had average latencies of 12.7 +/- 1.8 and 88.2 +/- 13.1 (SE) ms, respectively. Latencies of responses to SPL stimulation were significantly shorter and averaged 8.1 +/- 0.9 and 46.1 +/- 7.1 ms. Magnitudes of early responses to SPL stimulation were significantly greater than responses to CPS stimulation; however, late responses were not different. 4. Responses to CPS stimulation were inhibited by a prior conditioning stimulus applied to SPL. Greatest inhibition occurred at a conditioning-test interval of 40 ms, and inhibition lasted for at least 300 ms. Inhibition of responses to SPL stimulation could be evoked by conditioning stimuli applied to CPS; however, the inhibition was significantly less than that evoked by SPL stimulation on responses to CPS stimulation. 5. Thirty-eight neurons were tested for responses to injection of bradykinin (4 micrograms/kg) into the left atrium. Discharge rate of 17 cells increased from 5 +/- 2 to 12 +/- 4 Hz. Four cells were tachyphylactic to repeated injections. Injections of bradykinin into the thoracic aorta did not significantly alter cell activity. Bilateral cervical vagotomy had no effect on responses to intracardiac bradykinin. 6. The results indicate that lower thoracic SRT and STT neurons are excited by CPS stimuli including noxious stimulation of the heart. However, comparison of these responses with previously reported responses of upper thoracic SRT and STT neurons indicate that there is a decrease in effectiveness of CPS stimuli from upper to lower thoracic segments. Convergence of CPS and abdominal inputs onto lower thoracic pain pathways could explain abdominal pain that is occasionally associated with cardiac disease.

Animals↗
PubMed1995

Frequency and loss dependence of the protective effects of the olivocochlear pathways in cats.

1. In the previous manuscript I suggested a frequency dependency to olivocochlear bundle (OCB)-mediated protection from loud sound by showing protection for binaural compared with monaural 11-kHz exposures but not 3-kHz exposures of the same intensity and duration. To determine whether this was the case, experiments were carried out in barbiturate-anesthetized cats using the paradigm of a unilateral brain stem incision to deefferent one cochlea in each animal before presentation of a binaural loud sound exposure. With equal-intensity, equal-duration binaural exposures, in different groups protection in OCB-intact compared with OCB-cut ears was seen only for exposures at 11, 15, or 20 kHz, but not at 3 or 7 kHz, suggesting that OCB-mediated protection was found only for higher-frequency exposures. This would be consistent with the OCB-mediated protection in guinea pig studies where 10-kHz exposures were used and its absence in a study in cats where 6-kHz exposures were used. However, this conclusion had to be qualified by the fact that the lower-frequency exposures resulted in smaller threshold losses than did the higher-frequency exposures. 2. To determine whether OCB-mediated protection could be obtained for lower-frequency exposures that were made as damaging as or more damaging than the high-frequency exposures, longer-duration, lower-frequency exposures were used. OCB-mediated protection could then be obtained for exposure at 7 kHz, 100 dB SPL for 15 min but not at 3 or 5 kHz, 100 dB SPL for 20 min or at 3 kHz, 100 dB SPL for 40 min or 106 dB SPL for 20 min. Finally, when large threshold losses were produced with exposure at 3 kHz, 106 dB SPL for 40 min, OCB-mediated protection could be obtained for this low-frequency exposure too. These effects suggested that there were different "activation threshold" for OCB-mediated protection as a function of exposure frequency. To determine whether this also applied for the higher-frequency exposures (11, 15, and 20 kHz), all of which had elicited OCB-mediated protection when presented at 100 dB SPL for 10 min, these exposure frequencies were presented at 100 dB SPL for 7 min to produce low threshold losses. Now protection was found for the 11- and 15-kHz exposures but not for the 20-kHz exposure. 3. Thus the activation threshold for OCB-mediated protection varied in a frequency-dependent manner.(ABSTRACT TRUNCATED AT 400 WORDS)

Action Potentials↗
PubMed1978

Prolactin suppression by (-) delta-9-tetrahydrocannabinol (THC): involvement of serotonergic and dopaminergic pathways.

(-) delta-9-Tetrahydrocannabinol (THC) was previously shown to suppress serum PRL levels (SPL) in rats. In the present study, various pathways by which THC suppresses PRL secretion were investigated. THC abolished the elevated SPL induced by either 5-hydroxytryptophan or melatonin. The SPL suppression after THC treatment was abolished upon treatment with cyproheptadine. These results suggest on involvement of a serotonergic pathway in the suppressive effect of THC on PRL secretion. Elevated SPL induced by a low dose of the dopaminergic blocker pimozide was suppressed after treatment with THC. However, elevated SPL, induced by a high dose of pimozide or by any dose of perphenazine (a less specific dopaminergic blocker), were not reduced by combined treatment of either of these drugs with THC. It seems that THC also enhances the dopaminergic activity in the pathway that controls PRL secretion. In addition, the pimozide-induced SPL elevation dropped upon combined treatment of cyproheptadine and pimozide. As cyproheptadine alone, and in the dose used, did not affect SPL, it is proposed that the serotonergic and dopaminergic pathways that control PRL secretion do not necessarily act independently of one another.

Animals↗
PubMed1993

Hemodynamic effects of short-term noise exposure--comparison of steady state and intermittent noise at several sound pressure levels.

The purpose of the present study was to investigate the extent of blood pressure elevation during noise exposure, to elucidate the underlying hemodynamic mechanisms and to assess baroreceptor cardiac reflex sensitivity in connection with blood pressure elevation. Twenty-two young normotensive males participated in the experiment and underwent six noise exposure conditions of 20 min each: steady state and intermittent pink noises of 80 dB (sound pressure level (SPL)), 90 dB (SPL) and 100 dB (SPL). The results indicate that elevations in mean arterial pressure, as well as diastolic and systolic blood pressure, were significant or almost significant in the intermittent 100 dB (SPL) and 90 dB (SPL) conditions. Habituation occurred particularly with the steady state noises. In at least the intermittent 100 dB (SPL) condition, an increase in peripheral vascular resistance was the underlying hemodynamic mechanism of blood pressure elevation. Decreases in cardiac output and stroke volume were also associated with the peripheral vasoconstriction. Baroreceptor reflex sensitivity was maintained near the baseline level for all of the noise exposure conditions. Therefore, reflex sensitivity may not have been suppressed even in the intermittent 100 dB (SPL) condition during which blood pressure elevations occurred.

Adult↗
PubMed2000

Thyroid hyperactivity induced by methimazole, spironolactone and phenobarbital in marmosets (Callithrix jacchus): histopathology, plasma thyroid hormone levels and hepatic T4 metabolism.

To determine drug-induced hyperfunction of marmoset thyroids due to inhibition of synthesis or enhancement of metabolic elimination of thyroid hormones, males were orally administered 10 and 30 mg/kg/day methimazole (MMI), 30 and 100 mg/kg/day spironolactone (SPL), or 50 mg/kg/day phenobarbital (PB) for 4 weeks. MMI caused marked hypertrophy of follicular epithelial cells in accordance with a significant decrease in the plasma thyroxin (T4) level. Hypertrophied epithelial cells were filled with dilated rough endoplasmic reticulum and reabsorbed intracellular colloids, and the luminal surface was covered with abundant microvilli. The colloid included vacuoles positive to anti T4 immuno-staining. SPL and PB also caused similar histomorphological changes, although they were less severe than those due to MMI and were not clearly associated with decrease in the plasma T4 levels. Hepatic T4 UDPGT activities tended to increase due to SPL and PB treatment, however, which were not so significant as increases in microsomal cytochrome P-450 contents. Some animals treated with SPL and PB showed marked increases in thyroid weights due to inactive dilated follicles. In conclusion, hyperactivity of thyroid follicles was induced in marmosets not only due to inhibition of T4 synthesis produced by MMI but also because of enhancement of hepatic T4 elimination produced by SPL and PB. However, hypertrophic effects of SPL and PB were less severe than MMI, because plasma T4 levels were maintained at almost pretreatment or control levels after SPL or PB treatment.

Animals↗
PubMed2004

Outcome studies among men with micropenis.

Adult stretched penile length (SPL) was determined among 22 males who were diagnosed with micropenis. These adult SPL values were compared with SPL at the time of diagnosis, age of diagnosis and etiologic category in 20 men who were diagnosed before puberty. A portion of this group completed a structured questionnaire interview, the Social Adjustment Self Report Questionnaire and the Hopkins Symptom Checklist to assess social and psychosexual milestones and the presence of psychiatric morbidity. Results show that the majority of men who had been diagnosed with micropenis had an adult SPL within 2 standard deviations of the normal adult mean, with only a minority showing values below this. It appeared that men with micropenis might have greater than average interval SPL growth between diagnosis and adulthood; it remains unclear whether this supranormal growth represents a catch-up phenomenon or results from augmentation by intermittent androgen therapy. There was no clear relationship between SPL at diagnosis and SPL in adulthood. The responses to the questionnaires indicated that men who had been diagnosed with micropenis were comparable to control men in regard to gender issues, body image, social fitness, sexuality, work, family adjustment and the presence of psychopathology.

Adult↗
PubMed1993

The effect of endocochlear potential suppression upon susceptibility to acoustic trauma.

In the present study we investigated the influence of decreased endocochlear potential (EP) on acoustic trauma. Guinea pigs with decreased EP following i.v. administration of furosemide (FUR) and normal EP given physiological saline solution (PSS) i.v. instead of FUR were exposed to 2 kHz pure tone ranging from 110 to 130 dB SPL for 5 min. The input-output curves of the compound action potential (CAP) before acoustic overstimulation were compared with those at 2 h after the exposure. In 125 and 130 dB SPL exposure there was no difference in threshold shift between the FUR and PSS groups. In 115 and 120 dB SPL exposure, however, the threshold shift of the FUR group was significantly smaller than that of the PSS group. There was no significant difference between the two groups in 110 dB SPL exposure. These results indicate that the threshold shift of the CAP is mainly due to excessive vibration of the basilar membrane in the greater stimulus groups (125-130 dB SPL) but that the energy exhaustion of the hair cells to a certain extent participates in the threshold shift when the stimulus is milder (115-120 dB SPL). It is concluded that susceptibility to acoustic trauma of a milder intensity (115-120 dB SPL) is reduced when the energy consumption rate of the organ of Corti is decreased by EP suppression.

Acoustic Stimulation↗
PubMedDate not supplied

Effects of relative levels of the primary tones on distortion product otoacoustic emissions in normal-hearing subjects.

This study investigated the effects of the relative levels of the two primary tones, L1 and L2, on the amplitude of distortion product otoacoustic emissions (2F1-F2). Testing was conducted with a commercially available system for measuring DPOAEs (Grason-Stadler, GSI-60). The intensity of the lowest primary tone (L1) remained constant at 75, 65, 55 or 45 dB SPL while L2 varied over a 20 dB range around L1, i.e. L1-L2 was -5, 0, 5, 10 or 15 dB. For example, when L1 was 75 dB SPL, L2 was presented at 80, 75, 70, 65 or 60 dB SPL. Thirty normal-hearing women were presented with 11 pairs of primary tones having geometric means ranging from 531 Hz to 5531 Hz. A constant F2:F1 ratio of 1.21 was used. The results revealed that when L1 was 75 dB SPL, the largest distortion products were observed across all frequencies for the 0 dB condition (L1=75 dB; L2=75 dB) and -5 dB condition (L1=75 dB; L2=80 dB). When L1 was 65 dB SPL, the largest DPs were obtained across all frequencies for the 5 dB condition (L1=65 dB; L2=60 dB). For L1=55 dB SPL, the largest DPs were obtained across all frequencies for the 5 dB (L1=55 dB; L2=50 dB) and 10 dB (L1=55 dB; L2=45 dB) conditions. No mean DP differences were observed among relative levels (-5 dB to 15 dB) when L1 was 45 dB SPL; however, the 15 dB condition (L1=45 dB; L2=30 dB) at 5531 Hz resulted in fewer identifiable responses than the other relative levels.

Acoustic Stimulation↗
PubMed1988

Immunomodulation of intradermal mammary carcinoma using staphage lysate in a rat model.

Staphage lysate (SPL), a preparation of Staphylococcus aureus obtained by bacteriophage lysis, is an interferon-inducer and stimulator of T and B lymphocytes. Does SPL, as an immunopotentiator, have an effect on the growth and metastases of an intradermal mammary carcinoma? To answer this question, a study using SPL in female Fischer rats injected with 7 x 10(6) viable 13762 mammary tumor cells on the midback were used. Four groups were created with 10 animals in each group. Group I was the control group. They received no treatment. Group II received 0.3 ml of medium in which SPL was carried on alternate days. Group III received 0.3 ml SPL on alternate days. Group IV were sensitized with dead staphylococcal organisms prior to SPL treatment as in Group III. Tumor diameters were recorded on days 10, 13, 17, and 21, and autopsies were performed to determine the extent of metastases. Histologic examination and serum antibody measurements were performed. The mean tumor diameters on day 21 were: Group I: 4.1 +/- 0.2 cm; Group II: 3.80 +/- 0.19 cm; Group III: 3.04 +/- 0.13 cm; and Group IV: 2.97 +/- 0.14 cm. Rats receiving SPL treatment in Groups III and IV had significantly smaller tumors (P less than .001). The incidence of axillary lymph node involvement was: Group I: 100%; Group II: 87.5%; Group III: 62.5%; and Group IV: 40%. Lung metastases were seen in all groups. Groups I and II had 100% incidence of grossly visible nodules, whereas Groups III and IV had 75% and 70% involvement. Gross findings were confirmed by microscopic examination.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2002

[Safety of gene therapy within cochlea, experimental study with guinea pig].

OBJECTIVE: To observe the safety of inoculation of recombinant adenovirus with human neurotrophin-3 (Ad-NT3) into cochlea and its effect on hearing function. METHODS: Twenty healthy guinea pigs were randomly divided into two groups: ten animals were inoculated with Ad-NT3 into the perilymphatic space after a small hole was drilled in the bony wall near tympanic scala of the base turn, while the other ten were introduced with artificial perilymphatic fluid (APF) as controls. Auditory brainstem response (ABR) were recorded before, immediately after and seven days after the inoculation. Seven days after the surgery, the animals were killed. Frozen sections and colloidin sections of cochlea were made and observed under microscope. Immunohistochemistry was used to detect the expression of NT3 protein in cochlea. RESULTS: The mean ABR threshold values were (35 +/- 3.7) dB SPL and (35 +/- 3.2) dB SPL before the inoculation, (40 +/- 2.5) dB SPL and (40 +/- 3.0) dB SPL immediately after the inoculation, and (35 +/- 3.0) dB SPL and (35 +/- 3.0) dB SPL seven days after inoculation in the Ad-NT3 group and AFP group respectively (all P > 0.05). The ABR-III latency of 100dB SPL click was (2.812 +/- 0.087) ms and (2.824 +/- 0.121) ms before inoculation, (2.793 +/- 0.093) ms and (2.796 +/- 0.095) ms immediately after inoculation, and (2.822 +/- 0.102) ms and (2.834 +/- 0.135) ms seven days after inoculation in Ad-NT3 and AFP groups respectively (P > 0.05). No difference of ABR threshold and latency was observed at different time points in both groups. Ad-NT3 protein was expressed within each turn of the cochlea, including spiral limbus, spiral ligament and ganglion cells. The cochlear structure remained intact with no sign of infection or cell degeneration. CONCLUSION: Gene therapy by means of introduction of trace AdNT3 into the perilymphatic space through pore in tympanic scala is safe, causing no structure change or hearing loss.

Adenoviridae↗
PubMed1983

[NK activity, TCGF production and generation of cell-mediated cytotoxicity in spleen cells from gastric cancer patients].

The in vitro cell-mediated immune reactivities of mononuclear cells separated from spleen (SPL) of gastric cancer patients were studied and, these were compared to those of peripheral blood mononuclear cells (PBL) from the same patient. The level of NK activity of SPL was slightly higher than that of PBL (p less than 0.2, by paired t test), as measured by 51Cr release assay using K562 cells as target. TCGF preparations, generated in cultures of PHA stimulated SPL or PBL, were also compared by quantitative assay. SPL produced in significantly larger amounts than PBL (p less than 0.05). Then, the generation of cell-mediated cytotoxicity in mixed cell culture was investigated in both cell populations. When these cells were cultured with B-lymphoblastoid cell line Raji, SPL had much more capacity to generate cytotoxic cells, compared to PBL (p less than 0.1). Moreover, SPL had significantly increased ability of induce concomitant cytotoxicity during sensitizing to normal allogeneic PBL in mixed lymphocyte culture as compared to PBL (p less than 0.005). These results appeared to demonstrate that SPL from gastric cancer patients had much more increased in vitro cell-mediated reactivities, when compared to those of PBL from these patients.

Cells, Cultured↗
PubMed1981

The role of macrophages and T-lymphocytes in glucan-mediated alteration of murine hemopoiesis.

We have investigated the mechanism of glucan-mediated increase of splenic (SPL) and decrease of bone marrow (BM) hemopoiesis in B6DF1 mice. To determine the involvement of macrophages in these phenomena, B6DF1 mice were treated with silica 24 hrs prior to glucan injection and then tested for BM and SPL CFU-GM and CFU-S activities. Silica treatment reduced significantly augmentation of SPL, but not the decrease of BM CFU-GM proliferation, indicating that the former phenomenon is macrophage dependent, whereas the latter is not. Since no change in BM or SPL CFU-S proliferation was observed after silica treatment, it appears that macrophages are not involved in glucan-caused alterations of CFU-S. Athymic mice (not possessing mature T cell functions) also exhibited decreased BM and increased SPL CFU-GM proliferation after glucan treatment; however, the SPL CFU-GM augmentation in athymic mice was not as dramatic. Hence, although glucan's action did not appear to be completely dependent on mature T-cells, these cells appear in some way to act with macrophages to enhance the proliferation of SPL CFU-GM after glucan treatment.

Animals↗
PubMed1993

Regional effects and mechanism of positive end-expiratory pressure in early adult respiratory distress syndrome.

OBJECTIVE: To test the hypothesis that positive end-expiratory pressure (PEEP) prevents the collapse of a given lung region when it is equal to or greater than the hydrostatic pressure superimposed (SPL) to that region. DESIGN: Intervention study with sequential levels of PEEP applied in random order to a cohort of patients with adult respiratory distress syndrome (ARDS). SETTING: Referral center for ARDS in a university hospital. PATIENTS: Ten ARDS patients (with Murray scores > 2.5). INTERVENTION: Basal computed tomographic (CT) section taken at 0, 2, 4, 5, 6, 8, 10, 12, 14, 15, and 20 cm H2O PEEP. MAIN OUTCOME MEASURES: Basal lung CT sections were divided into 10 equal levels from the ventral to dorsal surfaces. In each level SPL was measured from density and height. The inflation of the level was measured as the gas/tissue ratio (g/t); g/t changes with PEEP were defined as the g/t-P curve. The slope of the g/t-P curve was defined as level compliance (ie, the ratio of change in the g/t of the level to the change in pressure). A linear g/t-P curve was the criterion to detect inflation without recruitment (ie, new pulmonary units opening at a given pressure). A biphasic g/t-P curve (change of compliance after an inflection point) was the criterion to detect recruitment. Pflex was defined as the pressure at which the inflection point occurred. RESULTS: The SPL increased from level 1 (ventral) to level 10 (dorsal) (r = .91; P < .01). The number of linear g/t-P curves decreased from level 1 to level 10 (r = .98; P < .01), while the number of biphasic g/t-P curves increased (r = .95; P < .01). The Pflex increased from level 1 to 10 (r = .97; P < .01) and Pflex was similar to SPL (Pflex = 1.05 + 0.9 SPL; r = .75; P < .01). CONCLUSIONS: The increased SPL causes compression atelectasis; this is prevented when PEEP to a given lung region is equal to or greater than the SPL.

Adolescent↗