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Biomedical subjects

J Golden

Publications and source records attributed to J Golden.

At least 19 recordsLinked to original sources
PubMed1995

'Membranous aplasia cutis' with hair collars. Congenital absence of skin or neuroectodermal defect?

BACKGROUND: The skin and the nervous system are both derived from ectoderm. Separation of neural ectoderm from epithelial ectoderm occurs concurrently with the closure of the neural tube. This chronologic association may explain the cutaneous abnormalities often found overlying neural tube defects. A ring of dark long hair encircling a congenital scalp lesion (the hair collar sign) is one such marker and is often associated with encephaloceles, meningoceles, and heterotopic brain tissue. OBSERVATIONS: We describe six children with aplasia cutis who displayed the hair collar sign. Aplasia cutis is a relatively heterogeneous disorder; however, these lesions had a unique and strikingly similar appearance. This subtype of aplasia cutis, which we have termed membranous aplasia cutis, shares several clinical and histologic features with cranial neural tube defects. CONCLUSIONS: We propose that membranous aplasia cutis is a form fruste of a neural tube defect and may be derived from a similar embryological defect. Recent advances in the understanding of cranial neural tube closure may provide support for this hypothesis.

Atrophy↗
PubMed1992

Pulmonary hypertension: pulmonary flow quantification and flow profile analysis with velocity-encoded cine MR imaging.

Velocity-encoded cine magnetic resonance (MR) imaging provides two-dimensional velocity maps of a cross-sectional area of a vessel. Pulmonary flow and flow patterns in the main pulmonary artery were analyzed with velocity-encoded cine MR imaging and Doppler echocardiography in 10 patients with pulmonary hypertension (PH), one patient with a dilated main pulmonary artery, and 10 healthy subjects, and these findings were compared. Peak systolic velocity measured with velocity-encoded cine MR imaging was similar to that measured with Doppler echocardiography in healthy subjects and in patients with PH. Velocity-encoded cine MR imaging demonstrated substantial differences in velocity across the vascular lumen in PH. The flow pattern in healthy subjects was different than that in patients with PH; the latter had lower peak systolic velocity and greater retrograde flow after middle to late systole. The retrograde flow observed in patients with PH reflected hemodynamic events, since it was inversely proportional to pulmonary flow volume and directly proportional to pulmonary resistance and cross-sectional area of the vessel. Velocity-encoded cine MR imaging demonstrates an inhomogeneous flow profile in PH and may serve as a noninvasive method to estimate pulmonary vascular resistance.

Adult↗
PubMed1990

Abnormal lung gallium-67 uptake preceding pulmonary physiologic impairment in an asymptomatic patient with Pneumocystis carinii pneumonia.

Pneumocystis carinii pneumonia was suggested by a diffuse, bilateral pulmonary uptake of gallium-67 in an asymptomatic, homosexual male with the antibody to the immunodeficiency virus (HIV) who was undergoing staging evaluation for lymphoma clinically localized to a left inguinal lymph node. Chest radiograph and pulmonary function evaluation, including lung volumes, diffusing capacity and arterial blood gases, were within normal limits. Bronchoalveolar lavage revealed Pneumocystis carinii organisms. In this asymptomatic, HIV-positive patient, active alveolar infection, evidenced by abnormal gallium-67 scanning, predated pulmonary physiologic abnormalities. This observation raises questions concerning the natural history of this disease process and the specificity of physiologic tests for excluding disease. It also has implications for the treatment of neoplasia in the HIV-positive patient population.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Structure-function relationships in rat brainstem subnucleus interpolaris: III. Local circuit neurons.

Intracellular recording, electrical stimulation, receptive field mapping, and intracellular injection of horseradish peroxidase were used to assess the response properties, collateral projections, and morphology of 44 local circuit (LC) neurons in the subnucleus interpolaris (Sp Vi) of the trigeminal brainstem complex of the rat. LC neurons were defined as those with axons restricted to brainstem areas receiving trigeminal primary afferent fibers. Thus, none were antidromically activated from the thalamus, tectum, or cerebellum, and their axons could be seen terminating exclusively within the trigeminal brainstem complex or reticular formation. All neurons sampled were discharged by innocuous or noxious mechanical stimulation of a restricted portion of the face or mouth. They were classified functionally as sensitive to vibrissae (N = 22), nociceptors (N = 9), guard hairs (N = 7), hairy skin (N = 3), or periodontia (N = 3). Fifty percent of the stained neurons were vibrissa sensitive. Twenty-one of these 22 responded to deflection of only one vibrissa. The remaining functional groups also had small receptive fields. Intracellular staining revealed a consistency in vibrissa-sensitive LC morphology. Somata were small to medium in size and multipolar. Their axons had an initial transverse trajectory and gave off recurrent collaterals which arborized extensively in the region of the soma. The parent axon then bifurcated. One branch traveled rostrally to subnucleus principalis while the other branch traveled caudally to subnucleus caudalis. The branches periodically sent collaterals into regions of the trigeminal complex corresponding to the transverse position of the soma. Dendrites extended 440 +/- 140 microns rostrocaudally, forming a tree with a transverse perimeter of 459 +/- 226 microns. Distal dendrites were thin and sinuous, had few spines, and extensively arborized adjacent to the soma. They ended in multiple swellings connected by slender processes. The stereotyped morphology of vibrissa-sensitive LC neurons differed from the variable morphologies of LC neurons activated by nociceptors, guard hairs, hairy skin, or periodontia. Although no group of neurons in one of these categories displayed a distinguishing morphological characteristic, they collectively had features which distinguished them from the vibrissa-sensitive neurons. Non-vibrissa-responsive neurons generally had more expansive, but less circular, dendritic and recurrent axonal arbors; dendrites had more spines, and axons often sent endings into the reticular formation.(ABSTRACT TRUNCATED AT 400 WORDS)

Action Potentials↗
PubMed1989

Studies of the structure of lung surfactant protein SP-A.

SP-A, a glycoprotein of pulmonary surfactant, consists of an NH2-terminal domain containing a collagen-like sequence and a COOH-terminal domain with sequence homology to several Ca2(+)-dependent lectins. We have compared the size, thermal stability, and secondary structure of recombinant SP-A, the product of a fibroblast line transfected with a single human gene encoding SP-A, with natural SP-A isolated from canine and human lungs. Our results suggest both recombinant and natural SP-A are assembled as large oligomers. More variability in the degree of oligomerization was observed with recombinant human SP-A than with natural canine SP-A. As shown by collagenase digestion, the full assembly of protein subunits was dependent on an intact collagen-like domain. The cysteines in the noncollagen domain of SP-A form intrachain bonds between residues 135-226 and 204-218. The circular dichroism spectra of both recombinant and natural SP-A were consistent with the presence of a collagen-like triple helix. As determined by the change in ellipticity at 205 nm, the thermal transition temperatures of canine, natural human, and recombinant SP-A were 51.5, 52.3, and 42.0 degrees C, respectively. These results suggest differences in the assembly and stability of the natural and recombinant proteins.

Amino Acid Sequence↗
PubMed1989

Noninvasive evaluation of pulmonary artery pressure during exercise by saline-enhanced Doppler echocardiography in chronic pulmonary disease.

To determine the feasibility of noninvasive determination of right ventricular systolic pressure (RVSP) during a graded-exercise protocol, saline contrast-enhanced Doppler echocardiography of tricuspid insufficiency was performed in 36 patients with chronic lung disease and 12 normal controls. In the patients with chronic pulmonary disease, symptom-limited, incremental supine bicycle exercise and pulse oximetry were performed on and off high-flow oxygen. Technically adequate Doppler studies were initially obtained in 20 patients (56%) at rest and 14 (39%) on exercise; these numbers increased to 33 (92%) and 32 (89%), respectively, after enhancement with agitated saline (both p less than 0.001). In 10 patients with chronic lung disease who had simultaneous hemodynamic monitoring during exercise, the correlation between Doppler and catheter measurements of pulmonary artery systolic pressure was close (r = 0.98). Among controls, RVSP increased from 22 +/- 4 at rest (mean +/- SD) to 31 +/- 7 mm Hg at peak exercise. In patients with chronic lung disease, RVSP increased from 46 +/- 20 to 83 +/- 30 mm Hg (both p less than 0.001 vs. controls). Despite normal resting values for RVSP in 28% of study patients, nearly all showed abnormal increases in RVSP during supine bicycle exercise. Increases in RVSP during exercise were greatest in patients who showed oxyhemoglobin desaturation. The short-term administration of oxygen significantly blunted the increase in RVSP during exercise. Saline contrast-enhanced Doppler evaluation of tricuspid insufficiency seems a potentially valuable noninvasive method of determining the exercise response of RVSP in patients with chronic pulmonary disease.

Adult↗
PubMed1988

Structure and function of barrel 'precursor' cells in trigeminal nucleus principalis.

Intracellular recording, electrical stimulation, receptive field mapping, HRP injection, and computer reconstruction techniques were used to study principalis cells in rat. They (n = 80) responded within 1.2 +/- 0.2 ms of trigeminal ganglion shocks and 69% were antidromically activated by thalamic shocks; 69% were vibrissa-sensitive, of which 80% responded to only a single vibrissa. The remainder responded only to guard hairs, skin, teeth, or nociceptors. Stained thalamic-projecting cells with one vibrissa receptive fields had stereotyped morphologies. Small somata gave rise to dendrites which extended only a short distance from the soma, where they branched extensively. Each tree was polarized, spanning no more than a hemisphere around the soma; however, there was no consistent direction of polarity. Dendritic trees extended 68 +/- 14, 95 +/- 48, and 91 +/- 29 micron in the transverse, sagittal and horizontal planes, respectively. Dendritic spines were rare, yet swellings were common. Axons never branched locally.

Action Potentials↗
PubMed1988

Transbronchial biopsy without fluoroscopy in patients with diffuse roentgenographic infiltrates and the acquired immunodeficiency syndrome.

Transbronchial biopsy with the flexible fiberoptic bronchoscope is usually performed with the assistance of fluoroscopy in order to increase diagnostic yield and decrease the incidence of pneumothorax. We have compared the results of transbronchial biopsy performed with or without fluoroscopic guidance in patients with diffuse roentgenographic infiltrates who had or were suspected of having the acquired immunodeficiency syndrome. Neither the sensitivity for Pneumocystis carinii (88.5 versus 92%) nor the percentage of patients developing pneumothoraces after transbronchial biopsy (8.6 versus 11.1%) was significantly different in those patients who had the procedure without fluoroscopic guidance compared with those in whom fluoroscopy was used. There were no patients with significant hemorrhage or deaths in either group. This complication rate compares favorably with other reports of transbronchial biopsy in immunocompromised patients in which fluoroscopy was used. "Blind" transbronchial biopsy is a safe and effective diagnostic procedure in this patient population.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Gallium lung scintigraphy in amiodarone pulmonary toxicity.

We sought to assess the role of gallium-67 lung scintigrams in the evaluation of amiodarone pulmonary toxicity. Images and laboratory studies were evaluated in 54 patients who had chest radiographs and scintigraphic studies during amiodarone treatment of more than one month's duration among 561 patients receiving the medication for refractory arrhythmias. There were 22 patients with pulmonary symptoms and clinical evidence of amiodarone pulmonary toxicity (group 1); 19 patients had other causes for pulmonary symptoms (group 2); and 21 patients were without symptoms or other clinical evidence of pulmonary toxicity (group 3). There was no difference among groups in treatment duration or total amiodarone dose. Symptomatic presentation could not differentiate between group 1 and group 2 patients. However, radiographic findings of isolated pulmonary congestion or a normal radiograph in the presence of symptoms made amiodarone toxicity unlikely, while the appearance of new, dense radiographic infiltrates--often in a nodular distribution--were more frequent among group 1 patients (p less than 0.01). During symptomatic periods, 18 of 22 group 1 patients had abnormal gallium lung uptake, while four revealed more subtle serial changes but there was only one abnormal scintigram among symptomatic group 2 patients. Nonspecific radiographic abnormalities in patients with pulmonary symptoms on amiodarone therapy were rarely attributed to toxicity in the presence of a normal scintigram. One group 3 patient developed scintigraphic abnormalities early during amiodarone treatment, suggesting toxicity in the presence of a normal chest x-ray examination. Comparison of radiographic and scintigraphic studies performed during symptoms with those performed prior to symptom development best indicated the diagnosis, while comparison with later images assessed the efficacy of treatment. Diffusion capacity testing and transbronchial biopsy were sensitive but not specific for the diagnosis of amiodarone toxicity. Gallium image abnormalities parallel the development of amiodarone pulmonary toxicity and aid this diagnosis, especially when the chest radiograph is abnormal and ambiguous. Serial increments in scintigraphic abnormality appear especially helpful for diagnosis in the population at risk.

Adult↗
PubMed1987

Automatic respiratory failure: sleep studies and Leigh's disease (case report).

A 34-year-old woman with a history of chronic nephropathy, kidney transplant rejections, and repeated hemodialysis developed symptoms of automatic respiratory failure during all states of sleep. The neuropathologic examination revealed symmetric brainstem lesions, explaining the sleep-related respiratory failure. Histology affirmed the diagnosis of Leigh's disease.

Adult↗
PubMed1987

Determination of obstructive site in obstructive sleep apnea.

Patients with obstructive sleep apnea syndrome (OSAS) may have airway obstruction at various levels, including the uvula-soft palate complex, base of tongue, and/or possibly other sites. For patients with tongue base and/or laryngeal obstruction, uvulopalatopharyngoplasty (UPPP, ppp) will not alleviate the obstruction. Prior authors have proposed that the hyoid bone position as determined by cephalometric x-rays can predict which patients have obstruction at a lower site than the soft palate. In this study, patients with obstructive sleep apnea syndrome were evaluated with polysomnographic testing, fiberoptic endoscopy, and cine-CT scans (Imatron Scanner with multiple level rapid sequence scans) in an attempt to determine precisely the site of airway obstruction. Measurements of airway size taken at the time of fiberoptic pharyngoscopy were compared with those determined by the cine-CT studies. Initial results revealed that fiberoptic pharyngoscopy in the sitting and supine positions was helpful in confirming pharyngeal airway sites with smaller diameters in awake patients. However, the cine-CT exam performed in both sleeping and awake states provided more direct data regarding the airway during sleep. We feel that with more clinical experience the cine-CT technique will prove to be the most helpful study for identification of the obstructive airway site in obstructive sleep apnea syndrome.

Airway Obstruction↗
PubMed1986

MR characteristics of benign lymph node enlargement in sarcoidosis and Castleman's disease.

The magnetic resonance characteristics of mediastinal and hilar lymphadenopathy were reviewed in five patients with sarcoidosis and one with Castleman's disease. Although the T1 values of 26 nodes measured in patients with sarcoidosis ranged from 390 to 786 msec (mean 549 msec; SD 88 msec), the mean values recorded for each patient were quite similar (range 501-616 msec). T2 values ranged from 40 to 68 msec (mean 49 msec; SD 7 msec). In the patient with Castleman's disease T1 and T2 values measured 838 msec and 45 msec respectively. In comparison to T1 and T2 values we have recently measured in patients with proven mediastinal lymph node metastases from bronchogenic carcinoma, lymph nodes in the patients with sarcoidosis have significantly lower T1 (p less than .001) and T2 (p less than .05) values. However, because of significant overlap between the values recorded in these two groups, their differentiation may be difficult in individual cases.

Adult↗