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Biomedical subjects

J Sorenson

Publications and source records attributed to J Sorenson.

At least 19 recordsLinked to original sources
PubMed2001

Multiple tactile maps in the human cerebellum.

Functional imaging studies of the cerebellum have mostly investigated motor performance or have been limited to the anterior lobe and therefore the somatosensory representations in the human cerebellum have not been fully demonstrated. We used fMRI of the entire cerebellum during tactile stimulation of the hand and foot in six normal subjects. Our results demonstrate that the tactile projections to the cerebellum in humans are represented in both the anterior and posterior lobes. in agreement with previous functional imaging studies, our results show a large-scale, between-limb somatotopy comparable to that shown in early animal studies.

Adult↗
PubMed1999

Low neutral endopeptidase levels in bronchoalveolar lavage fluid of lung cancer patients.

Neutral endopeptidase (NEP) is a cell surface enzyme found in normal human lung and which hydrolyzes small bioactive peptides, some of which act as growth factors for normal and malignant airway epithelial cells. Expression of NEP varies widely in human lung tissue from different individuals. NEP is often expressed at low or undetectable levels in both small-cell and non-small-cell lung cancer, and inhibits the growth of lung cancer cell lines. Variation in the expression of NEP could be a factor in susceptibility to lung cancer. We hypothesized that NEP could be measured in bronchoalveolar lavage fluid (BALF) and that airway levels of NEP would be low in lung cancer patients as compared with normal controls. We measured NEP and total protein in cell-free BALF supernatant, and expressed the respective concentrations as a ratio. NEP levels showed wide variation in BALF of healthy volunteers. Most patients with lung cancer had no NEP detectable in BALF. The mean NEP/total protein ratio was significantly lower in patients with lung cancer (0.87 +/- 0.7 ng NEP/mg protein) than in normal healthy subjects (14.0 +/- 4.3, p < 0.0003). We conclude that NEP levels are highly variable in BALF of normal volunteers, and are low or undetectable in most BALF specimens from patients with lung cancer. Low NEP levels in the airways may be a factor in the pathogenesis of carcinoma of the lung.

Adult↗
PubMed1998

Digital subtraction indocyanine green angiography of occult choroidal neovascularization.

OBJECTIVE: This study aimed to use a new technique for ocular imaging, digital subtraction indocyanine green angiography (DS-ICGA), to evaluate patients with occult choroidal neovascularization (CNV). DESIGN: The design was a cross-sectional study of patients with occult CNV. PARTICIPANTS: A total of 31 eyes of 31 patients were studied. INTERVENTION: Digital subtraction of sequentially acquired indocyanine green angiographic frames was used to image the progression of the dye front in eyes with occult CNV. A method of pseudocolor imaging of the choroid was developed that allows differentiation and identification of underlying choroidal arteries and veins. RESULTS: The DS-ICGA of occult CNV showed consistent findings. Occult CNV was imaged with greater detail and in a shorter period of time than with conventional indocyanine green angiography. The fundus landmarks were retained with DS-ICGA much better than with conventional indocyanine green angiography. CONCLUSIONS: The DS-ICGA uses time to dissect the choroidal circulation. With DS-ICGA, occult CNV could be imaged more quickly and in greater detail than with conventional imaging techniques. The DS-ICGA may improve the authors ability to image, and subsequently treat, occult CNV.

Angiography, Digital Subtraction↗
PubMed1996

Peptide amidating activity in human bronchoalveolar lavage fluid.

Monitoring respiratory epithelial biology may reveal individuals with incipient lung cancer. The expression of neuroendocrine (NE) markers in pulmonary epithelium is thought to be central to lung development, repair of injury and may contribute to carcinogenesis. In this study, we evaluate several candidate NE markers to determine the feasibility of prospective analysis of clinical specimens. The potential NE markers include the enzyme L-DOPA decarboxylase (DDC), the neuropeptide gastrin releasing peptide (GRP), and peptidyl-glycine alpha-amidating monooxygenase (PAM), the bifunctional enzyme responsible for the final bioactivation step of many neuropeptides. A comparison of PAM activity and DDC levels in 30 lung cancer cell lines indicated that peptide amidating activity may be an indicator of NE status. Bronchoalveolar lavage (BAL) fluid from subjects at risk of developing second primary lung cancer and from volunteers was obtained. The activity of the first PAM enzyme, peptidylglycine alpha-hydroxylating monooxygenase (PHM), ranged from not detectable to 507 pmol/h/mg protein in 57 specimens. The second PAM enzyme, peptidylamidoglycolate lyase (PAL), ranged from not detectable to 414 pmol/h/mg protein in 56 specimens. Using cluster analysis by the average linkage method, a group of enzyme values with PHM greater than 230 pmol/h/mg protein was determined. Long-term follow-up of these patients for new second primary lung cancers may help to determine the potential predictive value of PAM detected in the BAL fluid.

Biomarkers, Tumor↗
PubMed1995

National assessment of physicians' breast-feeding knowledge, attitudes, training, and experience.

OBJECTIVE: Previous reports have demonstrated that physician counseling can improve rates of breast-feeding initiation and duration but suggest that physicians are ill-prepared for this role. It is unclear whether residency training for pediatricians, obstetrician/gynecologists, and family physicians provides the knowledge and skills necessary for effective breast-feeding promotion. DESIGN: Survey. PARTICIPANTS: A national random sample of 3115 residents and 1920 practicing physicians in pediatrics, obstetrics/gynecology, and family medicine. OUTCOMES: Assessment of breast-feeding knowledge, attitudes, training, and experience. RESULTS: Overall response rate was 68%. All groups demonstrated significant deficits in knowledge of breast-feeding benefits and clinical management; for example, less than 50% of residents chose appropriate clinical management for a breast-fed jaundiced infant or a breast abscess. Practicing physicians performed slightly better, but still more than 30% chose incorrect advice for mothers with low milk supply. Residents reported that their breast-feeding instruction consisted mainly of didactic lecture, not patient experience. Only 55% of senior residents recalled even one instance of precepting related to breast-feeding, and less than 20% had demonstrated breast-feeding techniques at least five times during residency. Regarding preparation for breast-feeding counseling, more than 50% of all practicing physicians rated their residency training as inadequate. Overall, physician involvement in breast-feeding promotion was endorsed by 90% of respondents, yet only half rated themselves as effective in counseling breast-feeding patients. The greatest predictor of physician self-confidence was previous personal or spousal breast-feeding experience. CONCLUSIONS: In this national sample of residents and practicing physicians in three specialties, physicians were ill-prepared to counsel breast-feeding mothers. Deliberate efforts must be made to incorporate clinically based breast-feeding training into residency programs and continuing education workshops to better prepare physicians for their role in breast-feeding promotion.

Breast Feeding↗
PubMed1995

Indocyanine green videoangiography of idiopathic polypoidal choroidal vasculopathy.

PURPOSE: To identify the precise choroidal abnormalities associated with idiopathic polypoidal choroidal vasculopathy (IPCV), patients with IPCV were examined with indocyanine green (ICG) videoangiography. METHODS: Twelve patients with IPCV were examined using standard clinical, fluorescein, and ICG videoangiographic techniques. RESULTS: Indocyanine green videoangiography showed two basic choroidal vascular changes: a branching network of vessels in the inner choroid, and vascular dilations at the border of the network of vessels. The vascular dilations appeared to be associated with the exudative and hemorrhagic manifestations of IPCV. CONCLUSION: The choroidal vasculopathy seen in IPCV is distinct from the changes seen in other choroidal abnormalities. Recognition of these changes aids in diagnosis and patient management, since the clinical implications of IPCV differ from those of other similar entities.

Adult↗
PubMed1992

The effects of carbamazepine on stuttering.

No pharmacological treatment protocol has proven generally useful for all patients who stutter. Various medications, behavior therapy, relaxation, suggestion, and social-based therapies have been used. For this drug treatment study, two groups of adult stutterers were followed in an 8-week open label protocol. All subjects had in the past received speech therapy; none had been treated previously with medication for stuttering. The first group (N = 12) received a maximum dose of 800 mg of carbamazepine; the second group (N = 8) received a maximum dose of 400 mg of carbamazepine. Each patient served as his or her own control. A series of systematic speech tests was given weekly to determine the variability of fluency for each subject. A statistically significant change occurred for a number of "expectancy to stutter" characteristics. Subjects felt that they stuttered less often while taking carbamazepine. Subjective effects began before medication and continued after patients discontinued the medication. Struggle characteristics also subjectively decreased. However, no objective improvement was found. No change was found in percentage of words stuttered, reading improvement, or improvement in spontaneous speech rate. Interrater reliability showed a correlation of .996. Three carbamazepine serum level therapeutic windows were inspected with negative results. Interestingly, naive listener ratings did show a statistically significant improvement on carbamazepine versus placebo. Future anecdotal reports of pharmacological improvement of stuttering should be subjected to rigorous objective testing before general acceptance.

Adult↗
PubMed1990

Idiopathic polypoidal choroidal vasculopathy (IPCV).

Eleven patients, 40 to 71 years old, had a choroidal vasculopathy that led to hemorrhagic and exudative macular degeneration. The patients had peculiar polypoidal, subretinal, vascular lesions associated with serious and hemorrhagic detachments of the retinal pigment epithelium. This macular disorder, which we have named idiopathic polypoidal choroidal vasculopathy (IPCV), appears to represent a distinct entity that differs clinically and demographically from age-related macular degeneration (AMD) and other macular diseases associated with subretinal neovascularization. Recognition of this condition is important because it may have specific risk factors, natural course, and management considerations that differ from those of age-related macular degeneration.

Adult↗
PubMed1989

Comparison of speed of sound and ultrasound attenuation in the os calcis to bone density of the radius, femur and lumbar spine.

Broadband ultrasonic attenuation (BUA) between 0.1 and 0.6 MHz and speed of sound (SOS) were measured on the os calcis in normal women (n = 40), and women who had mild osteoporosis (n = 36). Comparisons were made between the ultrasonic properties and bone mineral densities (BMD) obtained using photon absorptiometry on the lumbar spine, proximal femur and radius shaft. In the osteoporotic women, whose spine BMD was significantly reduced, BUA and SOS were lower, to about the same degree of significance as radius BMD; ROC analysis demonstrated that for discrimination of spinal osteopenia, the area under the ROC curve was similar for radius BMD, SOS, and BUA. There was a modest correlation (r about 0.65) between either SOS or BUA on the os calcis and BMDs of the spine and radius. Correlations of the SOS and BUA with femoral neck BMD were lower (r about 0.4 to 0.5). The standard error of estimate for both spine and femoral neck BMD was too high (about 0.14 g cm-2) for os calcis measurements to be substituted clinically for densitometry at these fracture sites.

Absorptiometry, Photon↗
PubMed1987

Skin necrosis following fluorescein extravasation. A survey of the Macula Society.

Three patients developed cellulitis and skin necrosis following fluorescein dye extravasation. This experience prompted a survey of the Macula Society membership to determine whether this complication of fluorescein angiography is as rare as the paucity of cases in the literature suggests. In addition, the manufacturer was asked to reexamine the dye lot to determine whether an impurity had been introduced unintentionally during the manufacturing process. No impurity was found in the dye lots tested. The survey disclosed only nine additional cases of skin necrosis, leading to the conclusion that skin necrosis probably represents a rare, idiosyncratic reaction. Although fluorescein angiography remains a safe procedure, efforts should be directed toward prevention of dye extravasation. When extravasation does occur, prompt and proper medical attention with close follow-up study may minimize the likelihood of skin necrosis.

Aged↗
PubMed1979

Chromosome changes in a patient achieving complete remission in the acute phase of chronic myelogenous leukemia.

A patient with chronic myelogenous leukemia (CML) had a Philadelphia chromosome (Ph') [t(9q+;22q-)] in all cells and trisomy C in 13% of cells (later determined to be trisomy 8) at the time of diagnosis. After 21 months of intermittent treatment with busulfan, the acute phase developed with the appearance of an additional abnormality (trisomy ? 19). During a complete remission and reconversion to the chronic phase, trisomies 8 and ? 19 DISAPPEARed, although the Ph' remained. Following a period of marked thrombocytosis, a second relapse occurred with the reappearance of both marker chromosomes.

Adult↗