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Biomedical subjects

R G Wells

Publications and source records attributed to R G Wells.

At least 55 records · Page 3Linked to original sources
PubMed1992

Cloning of a human kidney cDNA with similarity to the sodium-glucose cotransporter.

We have used low-stringency screening with the human intestinal Na(+)-glucose cotransporter SGLT1 to isolate a 2,271-nucleotide cDNA (Hu14) from human kidney. This clone, which encodes a 672-residue protein, is 59% identical at the amino acid level to SGLT1 and has a similar number and arrangement of predicted membrane-spanning regions. It also shares significant sequence identity with other Na(+)-coupled transporters. Northern blot analysis suggests strong expression of Hu14 in kidney, but, unlike SGLT1, no significant expression in intestine. We have been unable to demonstrate definitive transport of any of a number of substrates (including amino acids, sugars, nucleosides, and vitamins) into Hu14 cRNA-injected Xenopus oocytes, although sequence conservation makes it likely that Hu14 represents another member of the Na+ cotransporter family, possibly a second Na(+)-glucose cotransporter.

Amino Acid Sequence↗
PubMed1992

Expression of mRNA (D2) encoding a protein involved in amino acid transport in S3 proximal tubule.

A rat kidney- and intestine-specific cDNA (D2) that induces high-affinity, Na(+)-independent uptake of cystine and dibasic and neutral amino acids into cRNA-injected Xenopus oocytes was recently isolated by expression cloning in our laboratory (R. G. Wells and M. A. Hediger. Proc. Natl. Acad. Sci. USA 89: 5596-5600, 1992). At present it is not known whether the D2-encoded protein functions as a transporter or as a transporter activator. To gain more insight into the role of D2 in renal amino acid transport, we studied the site of its expression in the kidney. This was determined by Northern blot analysis and by using a combination of in situ hybridization and immunocytochemistry with antibodies that recognize specific proximal tubule segments. D2 antisense RNA hybridized to the same tubular segments that were strongly positive for anti-ecto-adenosinetriphosphatase but negative for carbonic anhydrase type IV and the facilitated glucose transporter GLUT2. We conclude that D2 mRNA is strongly expressed in the rat kidney proximal tubule S3 segment, although there is weak hybridization to the S1 and S2 segments. The signal is absent in all other parts of the kidney. The S3 specific expression of D2 mRNA coincides with the site of high-affinity transport of cystine and other amino acids, consistent with the proposed involvement of D2 in these processes.

Amino Acids↗
PubMed1991

Managing miscarriage. The need for more than medical mechanics.

A compassionate physician recognizes the emotional as well as the physical needs of a woman who miscarries. The physical trauma is often short-lived, but the emotional aftermath may be prolonged. Dr Wells reviews the differential diagnosis and management of miscarriage and discusses the valuable role that a physician may take in alleviating the patient's feelings of guilt, grief, and frustration.

Abortion, Spontaneous↗
PubMed1991

Cervical lymphadenitis complicated by mycotic carotid artery aneurysm.

A case of mycotic carotid artery aneurysm due to cervical lymphadenitis in a four-year old child is presented. Sonography and computed tomography (CT) demonstrated an irregular fluid-containing neck mass, similar in appearance to an uncomplicated abscess. Continuity with the carotid artery was suggested on sonography, and CT demonstrated intense contrast enhancement of the liquid portion of the mass. Mycotic carotid artery aneurysm is a rare, but potentially fatal, complication of cervical lymphadenitis that is detectable with noninvasive diagnostic imaging studies.

Aneurysm, Infected↗
PubMed1990

Imaging of sacrococcygeal germ cell tumors.

Sacrococcygeal teratoma is the most common solid tumor in neonates. Malignant sacrococcygeal germ cell tumors also occur in infants and children. Diagnostic imaging studies help confirm the diagnosis of a clinically palpable sacrococcygeal mass, determine its relationship to other structures, and detect metastases. Despite the relative frequency of sacrococcygeal germ cell tumors, characteristics of these lesions as evaluated with computed tomography (CT) and magnetic resonance (MR) imaging have received little attention in radiologic literature. We outline important clinical information, review the spectrum of manifestations of these tumors with traditional imaging studies, and illustrate the value of CT and MR imaging for diagnosis and staging of sacrococcygeal germ cell tumors.

Diagnostic Imaging↗
PubMed1990

I-123 Iofetamine SPECT scan in children with neurological disorders.

I-123 Iofetamine (IMP) single photon emission computed tomography (SPECT) imaging of the brain in 42 patients (ages 14 days to 23 years) was compared with other localizing studies in children with neurological diseases. All had an EEG and at least one imaging study of the brain (computed tomography (CT) or magnetic resonance imaging (MRI), or both). Seventy-eight percent of the patients had an EEG within 24-72 hours of the IMP-SPECT scan. Thirty-five (83%) had a history of seizures, and the remainder had other neurological conditions without a history of seizures. In most cases, a normal EEG reading with normal CT or MRI result predicted a normal SPECT study. When the EEG was abnormal the majority of the IMP-SPECT scans were abnormal and localized the abnormality to the same region. A comparison with CT and MRI showed that structural abnormalities involving the cortex were usually well demonstrated with IMP-SPECT imaging. Structural lesions confined to the white matter were generally not detectable with IMP-SPECT. In a few cases, SPECT scans revealed abnormalities in deep brain areas not identified by EEG. IMP-SPECT imaging is a valuable technique for the detection and localization of abnormal cerebral metabolic activity in children with seizure disorders. A correlation with CT or MRI is essential for proper interpretation of abnormalities detected with IMP SPECT imaging.

Adolescent↗
PubMed1989

Hormone replacement before menopause. Is it a good idea?

The efficacy and safety of hormone replacement therapy for postmenopausal women are no longer issues of heated debate. The same cannot be said of hormone replacement therapy for women approaching menopause who, though still menstruating, have the emotional and physical symptoms of clinical menopause. In this article, Dr Wells presents a solid case advocating such treatment during the premenopausal stage of the climacteric.

Adult↗
PubMed1989

Bilateral complete ureteral obstruction and renal insufficiency secondary to granulomatous disease.

Chronic granulomatous disease is a rare disorder of neutrophil function that impairs the ability of phagocytes to react to infection and produces inflammatory lesions that may involve many organ systems. A young man recently presented with bilateral mid ureteral obstruction and renal insufficiency secondary to inflammation due to chronic granulomatous disease. To our knowledge, we believe this to be the only case of complete bilateral ureteral obstruction due to chronic granulomatous disease reported to date. A review of the disease, its pathogenesis and potential involvement of the urinary tract is presented.

Acute Kidney Injury↗
PubMed1989

Indications for chest roentgenogram in the febrile young infant.

A combined retrospective and prospective analysis of infants 60 days of age or less evaluated for fever (greater than or equal to 38.3 degrees C) or history of fever who received chest roentgenogram over a one-year period was performed to determine whether clinical characteristics were predictive of pneumonia. Of the 209 patients studied, 115 were reviewed prospectively and 94 retrospectively. Pneumonia was radiographically diagnosed in 16 patients. Individual clinical factors were not found to be highly predictive of pneumonia. However, infants with the following nine factors did not have pneumonia; illness in the summer months; absence of cough, dyspnea, and respiratory distress (grunting/flaring/retracting); respiratory rate less than 60; absence of rales and decreased breath sounds; presence of normal color; and white blood cell count less than 19,000/mm3. We recommend that these clinical characteristics be utilized to determine whether chest roentgenogram is warranted in the young infant evaluated for fever.

Diagnosis, Differential↗
PubMed1989

Imaging of the pediatric eye and orbit.

The spectrum of ocular and orbital pathology in the pediatric age group is quite different from that of adults. Imaging studies serve an important role in the diagnosis and management of many of these abnormalities. This review outlines the various abnormalities of the pediatric eye and orbit for which imaging studies are often required, including: infection, neoplasm, inflammation and infiltration, developmental anomalies, and trauma. The computed tomographic appearances of these abnormalities are emphasized. Additionally, the pertinent findings recorded with magnetic resonance imaging, scintigraphy, and radiography are described. Correlation of the results of imaging studies with pertinent clinical information allows the determination of specific diagnoses in most instances of pediatric orbital pathology.

Child↗