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Biomedical subjects

H Lane

Publications and source records attributed to H Lane.

At least 37 records · Page 2Linked to original sources
PubMed1995

Calcium absorption, endogenous excretion, and endocrine changes during and after long-term bed rest.

Negative calcium balance is a known consequence of bed rest, and is manifested in elevated urine and fecal calcium (Ca). Elevated fecal Ca can result from either decreased absorption, increased endogenous fecal excretion, or both. We measured the Ca absorption and endogenous fecal excretion in eight healthy male volunteers before and during 4 months of bed rest. Dual isotope (n = 6) or single isotope (n = 2) methods in conjunction with Ca balance were used to calculate true and net Ca absorption and endogenous fecal excretion. Stool Ca increased from 797 mg/day (mean intake 991 mg/day) to 911 mg/day during bed rest, whereas urine Ca excretion increased from 174 to 241 mg/day. True Ca absorption decreased from 31 +/- 7% of Ca intake pre-bed rest to 24 +/- 2% during bed rest, (p < 0.05) and returned toward pre-bed rest values within 5-6 weeks following reambulation. Endogenous fecal excretion did not change significantly, and therefore, most of the increased fecal Ca resulted from changes in absorption. However, in one individual, endogenous fecal Ca excretion was the major contributor to Ca loss. Ionized Ca and pyridinium crosslinks increased and 1,25(OH)2 vitamin D decreased during bed rest, similar to the decrease in Ca absorption; parathyroid hormone (PTH), calcitonin, serum albumin, phosphorus, and total serum Ca were unchanged. Although alkaline phosphatase, osteocalcin, and PTH were unchanged during bed rest, they were elevated during reambulation. These changes accompanied by increased Ca absorption and balance and decreased ionized and total serum Ca suggest a rebound in bone formation following immobilization.

Absorption↗
PubMed1995

Phonemic resetting versus postural adjustments in the speech of cochlear implant users: an exploration of voice-onset time.

Voice-onset time (VOT) was measured in plosive-initial syllables uttered by five cochlear implant users prior to and repeatedly at intervals after activation of their speech processors. In "short-term" experiments, the elicitation set was read after the subject's processor has been off for 24 h, then turned on them off again. Four out of five implant users increased voiceless and/or voiced VOTc (VOT corrected for changes in syllable duration) from preimplant baselines to final recordings made 1-3 years later. Measured acoustic correlates of speech "posture" (average SPL, F0, and low-frequency spectral slope) changed concurrently. Results in the short-term study were largely consistent with the long term. Significant multiple regressions relating changes in VOTc to accompanying changes in postural correlates were found in both studies. This outcome is consistent with hypotheses that predict changes in both VOTc and in postural correlates with the restoration of some hearing and that allow for linkages between the two. Some of the reliable VOTc increases obtained over the long term that were not correlated with postural changes may have been caused directly by auditory validation of articulatory/acoustic relations that underlie synergisms for phoneme production.

Cochlea↗
PubMed1994

Changes in voice-onset time in speakers with cochlear implants.

Voice-onset time (VOT) and syllable duration were measured for the English plosives in /Cad/(C = consonant) context spoken by four postlingually deafened recipients of multichannel (Ineraid) cochlear implants. Recordings were made of their speech before, and at intervals following, activation of the speech processors of their implants. Three patients reduced mean syllable duration following activation. Using measures of VOT and syllable duration from speakers with normal hearing [Volaitis and Miller, J. Acoust. Soc. Am. 92, 723-735 (1992)] and from the subjects of this study, VOT is shown to vary approximately linearly with syllable duration over the ranges produced here. Therefore, the VOT of each token was adjusted for the change in syllable duration of that token relative to the mean syllable duration in the first baseline session. This variable, labeled VOTc, was used to evaluate the effects on voicing of the speakers' renewed access to the voicing contrast provided by their implants. Preimplant, all four speakers characteristically uttered voiced plosives with too-short VOT, compared to the measures for hearing speakers. Voiceless plosive mean VOT was also abnormally short for two of the speakers, and close to normal for the remaining two. With some hearing restored, subjects made relatively few errors with respect to voicing when identifying plosives in listening tests, and three of the four speakers lengthened VOTc. The findings are interpreted as supporting the hypothesis that speakers use their hearing to calibrate mechanisms of speech production by monitoring the relations between their articulations and their acoustic output.

Cochlear Implants↗
PubMed1993

A quantitative immunohistochemical evaluation of lentigo maligna and pigmented solar keratosis.

Pigmented solar keratosis (PSK) is sometimes clinically indistinguishable from lentigo maligna, a form of malignant melanoma in situ. Occasionally histologic diagnosis is also difficult. Accurate diagnosis is essential, as the treatment and prognosis for each condition differs considerably. To determine whether there was a significant overlap in the number of melanocytes in these sun-damaged skin lesions, or whether immunohistochemistry might be helpful in the differential diagnosis, the authors examined skin biopsy specimens from 26 patients with obvious lentigo maligna and 15 patients with PSK using 3 monoclonal antibodies (HMB-45, NK1C3, and vimentin) and 1 polyclonal antibody (S-100 protein). Formalin-fixed paraffin sections were immunostained with each of the above antibodies, and immunopositive cells per mm2 of epidermis were counted. The difference between lentigo maligna and PSK counts was statistically significant at a level of P < .0001; furthermore, there was almost no overlap between the two groups. The sensitivity for the diagnosis of lentigo maligna was high with all antibodies. However, HMB-45 had the highest sensitivity and the lowest false-positive rate and was visually most pleasing. Using a cut-off count of 60 cells per mm2 of epidermis, HMB-45 had a sensitivity of 96% and a 0% false-positive rate. In this study, lentigo maligna was easily differentiated from PSK. The real value of immunohistochemistry in the differential diagnosis of these pigmented lesions should be tested in a prospective study using cases that are difficult to diagnose by routine light microscopy.

Adult↗
PubMed1992

Speech of cochlear implant patients: a longitudinal study of vowel production.

Acoustic parameters were measured for vowels spoken in /hVd/ context by four postlingually deafened recipients of multichannel (Ineraid) cochlear implants. Three of the subjects became totally deaf in adulthood after varying periods of partial hearing loss; the fourth became totally deaf at age four. The subjects received different degrees of perceptual benefit from the prosthesis. Recordings were made before, and at intervals following speech processor activation. The measured parameters included F1, F2, F0, SPL, duration, and amplitude difference between the first two harmonic peaks in the log magnitude spectrum (H 1-H2). Numerous changes in parameter values were observed from pre- to post-implant, with differences among subjects. Many changes, but not all, were in the direction of normative data, and most changes were consistent with hypotheses about relations among the parameters. Some of the changes tended to enhance phonemic contrasts; others had the opposite effect. For three subjects, H 1-H2 changed in a direction consistent with measurements of their average air flow when reading; that relation was more complex for the fourth subject. The results are interpreted with respect to: characteristics of the individual subjects, including vowel identification scores; mechanical interactions among glottal and supraglottal articulations; and hypotheses about the role of auditory feedback in the control of speech production. Almost all the observed differences could be attributed to changes in the average settings of speaking rate, F0 and SPL, which presumably can be perceived without the need for spectral place information. Some observed F2 realignment may be attributable to the reception of spectral cues.

Adult↗
PubMed1992

Effects of short-term auditory deprivation on speech production in adult cochlear implant users.

Speech production parameters of three postlingually deafened adults who use cochlear implants were measured: after 24 h of auditory deprivation (which was achieved by turning the subject's speech processor off); after turning the speech processor back on; and after turning the speech processor off again. The measured parameters included vowel acoustics [F1, F2, F0, sound-pressure level (SPL), duration and H1-H2, the amplitude difference between the first two spectral harmonics, a correlate of breathiness] while reading word lists, and average airflow during the reading of passages. Changes in speech processor state (on-to-off or vice versa) were accompanied by numerous changes in speech production parameters. Many changes were in the direction of normalcy, and most were consistent with long-term speech production changes in the same subjects following activation of the processors of their cochlear implants [Perkell et al., J. Acoust. Soc. Am. 91, 2961-2978 (1992)]. Changes in mean airflow were always accompanied by H1-H2 (breathiness) changes in the same direction, probably due to underlying changes in laryngeal posture. Some parameters (different combinations of SPL, F0, H1-H2 and formants for different subjects) showed very rapid changes when turning the speech processor on or off. Parameter changes were faster and more pronounced, however, when the speech processor was turned on than when it was turned off. The picture that emerges from the present study is consistent with a dual role for auditory feedback in speech production: long-term calibration of articulatory parameters as well as feedback mechanisms with relatively short time constants.

Adult↗
PubMed1991

Changes in speech breathing following cochlear implant in postlingually deafened adults.

Three postlingually deafened adults who received cochlear implants read passages before and after their prostheses were activated while their lung volumes were measured with an inductive plethysmograph that transduced the cross-sectional areas of the speaker's chest and abdomen. Lung volumes at the initiation and termination of the speakers' expiratory limbs, their average air flow, and the volume of air they expended per syllable were derived from tracings of calibrated lung volume displayed by computer. The activation of the speakers' cochlear prostheses was followed in every case by a significant change in average airflow, which rose for two subjects with initially low flow rates and fell for one subject who had a much higher average preimplant flow rate. These changes in average flow rate were accompanied by corresponding changes in volume of air expended per syllable, statistically reliable in two of the three cases. There were no significant changes in the levels at which speakers initiated their expiratory limbs, but one speaker, after his prosthesis was activated, reliably increased the level of air in his lungs at the end of expiratory limbs to an average value that no longer required him to draw on expiratory reserve volume.

Adult↗
PubMed1991

Speech deterioration in postlingually deafened adults.

Postlinngually deafened adults reading the Rainbow Passage differed from hearing-control subjects in producing greater pitch variability and mean pitch on stressed and unstressed vowels, greater fluctuations in pitch within sentences, less correlation of intrinsic pitch with vowel height and slower temporal parameters. When reading the Phonetic Inventory Sentences, they revealed less differentiation of place of articulation in fricative and plosive consonants. The present findings, taken together with those of longitudinal and implant studies, are applied to constraining models of the role of self hearing in the elaboration of speech.

Adult↗
PubMed1987

2,000-centiGray total lymphoid irradiation for refractory rheumatoid arthritis.

Because toxicity with the use of 3,000 centiGray (cGy) of total lymphoid irradiation (TLI) was observed in an earlier study, 2,000-cGy treatments were delivered in a 2-portal format to 7 patients and in a modified 3-portal fashion to 6 patients, as part of a randomized, investigator-blinded trial of TLI treatment for refractory rheumatoid arthritis. Analysis of combined data from the 13 patients revealed statistically significant improvement in 5 clinical indicators of disease activity at the end of TLI and 6 and 12 months later, accompanied by T4-specific immunosuppression. Management considerations resulted in the introduction of prednisone therapy in 5 patients, methotrexate in 4, and azathioprine in 1 during the interval of 8-12 months post-TLI. Herpes zoster occurred in 5 patients prior to the initiation of this additional therapy. These data indicate that, in patients with rheumatoid arthritis, a TLI dose of 2,000 cGy is sufficient to produce measurable benefit that lasts for 6 months, and that the improvement can be maintained at 12 months by the use of prednisone and methotrexate.

Adult↗
PubMed1983

T lymphocyte surface antigens in primates.

We examined the binding of peripheral blood mononuclear cells from various primate species to a panel of monoclonal antibodies with specificity for human T lymphocytes. A remarkable structural conservation of the erythrocyte rosette receptor on T cells between such phylogenetically distant primates as lemurs and man was found. Furthermore, it was demonstrated that the degree of sharing of other T cell-specific surface determinants between man and other primates reflects the phylogenetic distance between them. Moreover, these studies suggest the potential use of monoclonal antibodies for further structural and functional elucidation of T lymphocyte-specific surface structures.

Animals↗
PubMed1983

Circulating lymphocyte populations in Hodgkin's disease after mantle and paraaortic irradiation.

The effect of mantle and paraaortic radiation on peripheral blood lymphocytes was studied in 11 previously untreated patients with early stage Hodgkin's disease using a series of monoclonal antibodies defining immunoregulatory lymphoid cells. Immediately following the completion of radiotherapy, there was a significant reduction in the number of lymphocytes and the percent of circulating T cells. This acute decrease in T cells was due to a marked diminution in the number of inducer T cells, while the fraction of suppressor T cells remained constant. These changes persisted for up to 12 mo and were accompanied by a later increase in the fraction of circulating B lymphocytes and cells bearing surface Ia. It thus appears that mantle and paraaortic radiotherapy causes a relatively selective reduction in the inducer T-cell population. The implications of a change in the ratio of inducer to suppressor T cells is discussed.

Antibodies, Monoclonal↗
PubMed1983

T-cell surface antigens in a patient with blast crisis of chronic myeloid leukemia.

There is little evidence to suggest that T lymphocytes are involved in the leukemic process in chronic myeloid leukemia (CML). A case of CML in blast phase is described in which T-cell surface antigens were detected by immunofluorescence on the patient's blasts using monoclonal antibodies. In order to determine that the T-cell blasts were derived from the original CML clone, cells bearing the T3 antigen were isolated by fluorescence-activated cell sorting and chromosome analysis was performed. All metaphases examined had the Philadelphia chromosome, confirming their origin from CML.

Antigens, Surface↗
PubMed1981

The invariance of sentence performance structures across language modality.

Native users of American Sign Language were asked to manipulate sentences in four different ways: sign them at slow rate, parse them, make relatedness judgments of pairs of signs taken from each sentence, and recall the sentences. The data obtained from these four tasks (pause durations, parsing values, indices of relatedness and probe latencies) were used to construct hierarchical performance structures for each of the sentences. The resulting structures were highly similar across tasks; that is, performance structures are not task specific. The four measures at each sign boundary in each sentence were well predicted by a performance model, elaborated by Grosjean, Grosjean, and Lane for speech, that combines a parsing measure with a symmetry measure. Thus performance structures appear to be founded in the processing of language, be it visual or oral, and not in the properties of any particular communication modality.

Adult↗
PubMed1981

Effects of selenium on mouse mammary tumorigenesis and glutathione peroxidase activity.

The effects of supplemental selenium on 7,12-dimethylbenz(a)anthracene (DMBA)-induced and murine mammary tumor virus (MuMTV)-induced mammary tumorigenesis were investigated in BALB/c mice. Selenium (4-10 ppm), administered in the drinking water, inhibited mammary tumor formation in DMBA-treated mice. The higher doses of selenium (7-10 ppm) were tolerated well by the DMBA-treated mice and blocked mammary tumor formation by 80-90%. In addition, selenium at the lowest dose (4 ppm) inhibited the tumor-producing capabilities of a MuMTV-positive preneoplastic nodule outgrowth line by greater than 75%. The inhibition of tumor formation could not be attributed to an alteration in virus expression because there was no qualitative difference in the expression of of MuMTV proteins between selenium-treated and -untreated mice. Additionally, selenium-dependent glutathione peroxidase activity was detectable in normal virgin and preneoplastic mammary tissues of mice raised on a commercial diet and was increased 2-fold by 4 ppm supplemental selenium in the drinking water. These results demonstrate that supplemental selenium is an effective inhibitor of both chemical- and viral-induced mouse mammary tumorigenesis, and secondly, that the neoplastic transformation in, as well as the development of, preneoplastic lesions is sensitive to selenium-mediated inhibition.

9,10-Dimethyl-1,2-benzanthracene↗