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Biomedical subjects

S F Anderson

Publications and source records attributed to S F Anderson.

34 records · Page 2Linked to original sources
PubMed1997

Choroidal metastases resulting from carcinoma of the lung.

BACKGROUND: Choroidal metastases, the most commonly observed tumors of the choroid, are a frequent sequela of lung cancer. Carcinoma of the lung is the most common cancer. Choroidal metastatic tumors can be observed before or after the definitive diagnosis of a lung carcinoma. METHODS: A 42-year-old man, examined 1 month after reporting an ache and blurry vision in his left eye, was found to have an elevated, irregular-shaped choroidal lesion in the eye. The second patient, a 53-year-old man, was examined 1 week after reporting dim vision in the left eye. Diagnosed with non-small-cell lung carcinoma 5 months earlier, he was found to have bilateral choroidal lesions. RESULTS: The first patient was diagnosed with choroidal metastasis from adenocarcinoma of the lung 8 months after the initial presentation, confirmed after a fine-needle aspiration biopsy. The second patient had bilateral choroidal metastases from disseminated lung carcinoma. CONCLUSIONS: Metastases to the eye or orbit develop in approximately 0.7% to 12% of patients with lung cancer. Treatment regimens depend on the size and extent of the choroidal tumor, number of tumors, laterality, the visual status of the affected or nonaffected eye, the stage of cancer, and the age and general health of the patient. Prognosis is contingent on vital organ involvement and response to therapy. Preserving the patient's visual status may enhance the quality of remaining life.

Adenocarcinoma↗
PubMed1997

Paraocular sinus mucoceles.

BACKGROUND: Patients with paraocular sinus masses may manifest ocular complications, including orbital displacement, proptosis, diplopia, restricted extraocular muscles, decreased vision, chemosis, pain, and optic neuritis. METHODS: Two patients with paraocular sinus masses came to our clinic for examination. One had proptosis and orbital displacement and a chief symptom of increasing diplopia, along with dull brow pain and sudden decreased vision of the left eye. He was diagnosed with polypoid disease and mucoceles of the ethmoidal and frontal sinuses. The second patient experienced pain and swelling under his left eye. He had an upper respiratory tract infection with sinusitis, which in turn increased the size of the sinus cyst. RESULTS: Computed tomography (CT) of the sinuses and orbits was ordered for both patients and confirmed the presence of mucoceles in each case. The first patient's signs and symptoms decreased over 2 weeks, so surgical intervention at that time was not necessary. The second patient was treated with 60-mg pseudoephedrine q.i.d. and 250-mg amoxicillin/potassium clavulanate q.i.d. CONCLUSIONS: Mucoceles are slow-growing polyp-like cysts of the sinuses; these cysts may be sterile in composition or harbor purulent infection (mucopyocele). In either case; they are space-occupying lesions that increase in size as mucus secretions continue, and can be exacerbated by active sinusitis. Differential diagnosis includes thyroid eye disease, orbital pseudotumor, infection, trauma, benign or malignant tumors, encephalocele, or meningiocele.

Aged↗
PubMed1996

A mammalian SRB protein associated with an RNA polymerase II holoenzyme.

A large multisubunit complex containing RNA polymerase II, general transcription factors and SRB regulatory proteins initiates transcription of class II genes in yeast cells. The SRB proteins are a hallmark of this RNA polymerase II holoenzyme as they are found only in this complex, where they contribute to the response to regulators. We have now isolated a human homologue of the yeast SRB7 gene and used antibodies against human SRB7 protein to purify and characterize a mammalian RNA polymerase II holoenzyme containing the general transcription factors TFIIE and TFIIH. This holoenzyme is more responsive to transcriptional activators than core RNA polymerase II when assayed in the presence of coactivators.

Amino Acid Sequence↗
PubMed1996

Presumed ocular tuberculosis in an AIDS patient.

BACKGROUND: Prior to the advent of anti-tuberculosis medications, ocular manifestations of tuberculosis, including choroidal tubercles, were common. METHODS: A 46-year-old Hispanic male with a history of AIDS, tuberculosis and treated neurosyphilis presented for examination complaining of decreased vision in the left eye. Ophthalmoscopy revealed a large, elevated, juxtapapillary lesion consistent with a choroidal tubercle or an intraocular lymphoma. RESULTS: During follow-up, the lesion responded well to systemic anti-tuberculosis therapy. CONCLUSIONS: With the recent increase in incidence of tuberculosis in both th general population and AIDS patients, ocular manifestations of tuberculosis once thought to be rare may be increasing. Ocular tuberculosis should be considered in the differential diagnosis of patients presenting with intraocular masses, especially in individuals at high risk for exposure.

Acquired Immunodeficiency Syndrome↗
PubMed1995

UME6, a negative regulator of meiosis in Saccharomyces cerevisiae, contains a C-terminal Zn2Cys6 binuclear cluster that binds the URS1 DNA sequence in a zinc-dependent manner.

UME6 is a protein of 836 amino acids from Saccharomyces cerevisiae that acts as a repressor and activator of several early meiotic genes. UME6 contains, near the C-terminus, the amino acid sequence-771C-X2-C-X6-C-X6-C-X2-C-X6-C-, in which the spacings of the six Cys residues are identical to those found in 39 N-terminal Cys-rich DNA binding subdomains of fungal transcription factors. This sequence has been shown in GAL4 and other proteins to form a zinc binuclear cluster. In spite of the different location, the C-rich sequence, cloned and over-produced within the last 111 amino acid residues of UME6, UME6(111), forms a binuclear cluster and exhibits a Zn-dependent binding to the URS1 DNA sequence. The latter, TAGCCGCCGA, is required for the repression or activation of meiosis-specific genes by UME6. UME6(111) contains 1.8 +/- 0.4 mol Zn/mol protein and the Zn can be exchanged for Cd to yield a protein containing 1.9 +/- 0.1 mol Cd/mol protein. At 5 degrees C, 113Cd2UME6(111) shows two 113Cd NMR signals, with chemical shifts of 699 and 689 ppm, similar to those observed for 113Cd2GAL4(149). The magnitude of these chemical shifts suggests that each 113Cd nucleus is coordinated to four -S- ligands, compatible with a 113Cd2 cluster structure in which two thiolates from bridging ligands. The entire UME6 gene has been cloned and overexpressed and binds more tightly to the URS1 sequence than the zinc binuclear cluster domain alone. DNase I footprints of UME6 on URS1-containing DNA show that the protein protects the phosphodiesters of the 5'-CCGCCG-3' region within the URS1 sequence.

Amino Acid Sequence↗
PubMed1995

The anger recall interview and cardiovascular reactivity in women: an examination of context and experience.

Recent research has focused on the role of hostility as a risk factor for coronary heart disease. Hostility has been linked independently to cardiovascular mortality and, as a component of Type A behavior, to atherogenesis and myocardial infarction; however, the mechanisms by which hostility manifests its effects on the cardiovascular system have not been determined. In addition, hostility has been evaluated as a trait measure, with little emphasis on how anger-provoking episodes may be perceived by individuals. The present study seeks to evaluate the affective experience of hostility, through an anger recall interview, and relate qualities of that experience to one potential mechanism of cardiovascular risk, cardiovascular reactivity. Fifty-eight women, classified by structured interview as Type A or B, participated in an anger recall interview while their heart rate and blood pressure were monitored. Type A women manifested greater systolic reactivity when their anger was in response to frustration of autonomy needs, while Type B women exhibited greater heart rate reactivity in response to frustration of affiliation needs. All women who suppressed anger expression experienced higher pressor responses than women who expressed anger assertively. Future investigations may find the content of an interview as useful as the procedure itself in studies of cardiovascular reactivity.

Adolescent↗
PubMed1995

Solution structure of the Kluyveromyces lactis LAC9 Cd2 Cys6 DNA-binding domain.

The Zn2Cys6 DNA-binding domain has been identified by sequence homology in approximately forty fungal proteins, including the K. lactis LAC9 transcriptional activator. Using 1H NMR spectroscopy, we have determined the solution structure of a cadmium-substituted form of the LAC9 DNA-binding domain. We have complemented this approach by applying a series of 113Cd-1H NMR experiments, including several novel heteroTOCSY-based techniques. The DNA-binding domain forms a core of two alpha-helix/extended strand segments around the Cd2 binuclear cluster, with a network of amide proton-cysteinyl S gamma hydrogen bonds stabilizing the cluster. Comparison with other Zn2Cys6 domain structures provides insight into the common structural elements used in metal coordination and DNA binding.

Amino Acid Sequence↗
PubMed1995

Circumscribed choroidal hemangioma.

BACKGROUND: Circumscribed or solitary choroidal hemangioma is a relatively rare, benign vascular tumor. Because its appearance may mimic more serious intraocular lesions, eye care practitioners should be familiar with differential diagnosis and treatment options. METHODS: A patient presented with an asymptomatic, elevated, red-orange lesion above the macula in the right eye and a history of longstanding unexplained visual acuity loss in the eye. Intraocular lesions such as amelanotic melanoma, metastatic tumor, choroidal osteoma, disciform scar, serous detachment, and central serous chorioretinopathy can appear similar to circumscribed choroidal hemangioma (CCH) on ophthalmoscopy, but may be differentially diagnosed with fluorescein angiography, ultrasonography, and periodic observation. RESULTS: CCH requires various therapeutic options. Until the patient becomes symptomatic from visual loss secondary to serous macular detachment or subretinal neovascular membrane formation, no treatment is necessary. Laser photocoagulation is the preferred therapeutic intervention, and most patients will require a minimum of two sessions. A small percentage of individuals will progress to complete retinal detachment with profound visual loss regardless of therapy. Most CCHs remain stable in size and do not undergo malignant transformation. CONCLUSIONS: CCHs may be overlooked because of their initial subtle clinical appearance with no associated cutaneous or systemic anomaly. Even though CCH is a benign tumor, it may mimic more serious intraocular lesions and require a combination of ancillary tests for proper diagnosis. Depending on visual symptoms or potential threat to vision, management options include periodic observation, laser photocoagulation, cryotherapy, microwave therapy, and possible enucleation. CCH has little or no growth potential, but visual prognosis remains guarded due to significant secondary retinal changes that can occur over the tumor's surface. CCH must be considered in the differential diagnosis of an elevated intraocular lesion.

Aged↗
PubMed1994

Papilledema secondary to metastatic prostate disease.

BACKGROUND: Prostate cancer increases in incidence with age, and is common in older men. If allowed to progress or detected late, prostate cancer readily metastasizes to bone and accounts for about 11 percent of all cancer deaths. Associated conditions with prostate metastatic disease are anemia, pathological bone fractures, and paraplegia. Occasionally, prostate cancer may metastasize to the skull or spinal cord and result in papilledema. Two cases presenting with papilledema secondary to metastatic prostate disease are discussed.

Adenocarcinoma↗
PubMed1993

Central serous chorioretinopathy complicated by subsequent occipital lobe infarction and sinusitis in a drug abuser.

BACKGROUND: The presence of multiple occurring, simultaneously complicated clinical findings can be challenging. METHODS: A 39-year-old white male presented initially with central serous chorioretinopathy. Later, the patient reported a great deal of pain over his left eye with nasal vision loss. Comprehensive ophthalmic evaluation and neurologic consultation were invaluable in the diagnosis and management of the patient. RESULTS: Neurologic consultation along with computed tomography (CT) of the head with and without contrast enhancement along with magnetic resonance imaging (MRI) with and without gadolinium revealed lesions in the left occipital lobe, right cerebellum, and left thalamus area. In addition, bilateral maxillary and ethmoidal sinusitis were observed. CONCLUSIONS: Multiple events affecting vision are often related, sometimes not. However, co-existing factors can confound and obscure accurate diagnoses. Careful patient clinical and laboratory investigations are frequently necessary to elucidate correct diagnosis.

Adult↗
PubMed1992

Conformational changes of HIV reverse transcriptase subunits on formation of the heterodimer: correlation with kcat and Km.

The reverse transcriptase (RT) from the human immunodeficiency virus (HIV) is initially expressed as a 66-kDa protein and is subsequently proteolytically processed in vivo to form a 66-kDa/51-kDa heterodimer. Comparison of circular dichroism spectra of the 66-kDa, 51-kDa, and heterodimeric forms of RT indicates that the conversion is accompanied by dramatic changes in subunit conformation. The mean residue ellipticity per subunit at 220 nm decreases from -10.7 x 10(3) deg cm2 dmol-1 for the 66-kDa protein to -6 x 10(3) deg cm2 dmol-1 for the heterodimer. The same loss of ellipticity is observed whether the heterodimer is produced by proteolysis or by mixing a separately-expressed cloned 51-kDa subunit with the 66-kDa protein. Comparison with the spectrum of the cloned 51-kDa protein suggests that much of the conformational change arises from formation of the 51-kDa subunit but substantial changes occur in the remaining 66-kDa subunit as well. A kinetic analysis was performed to correlate these conformational changes with changes in enzyme function. Application of an integrated Michaelis-Menten equation to the catalysis of poly(dT) formation using a d(pT)20-poly(rA) primer-template shows that the kcat for the heterodimer is approximately half that of the 66 kDa enzyme, decreasing from 2.9 to 1.2 nucleotides/s upon formation of the heterodimer. However, km values for the primer-template decrease from 0.54 to 0.12 microM upon heterodimer formation. Thus, kcat/Km is 2-fold larger for the heterodimer, giving it a distinct catalytic advantage at undersaturating concentrations of enzyme and primer-template.(ABSTRACT TRUNCATED AT 250 WORDS)

Circular Dichroism↗
PubMed1991

Congenital optociliary shunt vessels.

Congenital optociliary shunt vessels have rarely been reported in the literature. Three cases of congenital optociliary shunt vessels are presented: two with unilateral shunt vessels and one with bilateral shunt vessels. All three patients were asymptomatic with good visual acuity and essentially normal visual fields with no apparent change in visual function over time. Associated with congenital optociliary shunt vessels is an anomalous bifurcation of the vasculature. Diagnostic implications of optociliary shunt vessels include 1) congenital variations, or 2) acquired secondary to a long-standing venous congestive event as occurs with optic nerve sheath meningioma, central retinal vein occlusion, papilledema, hyaloid bodies of the optic nervehead, dysthyroid optic neuropathy, and papillophlebitis.

Aged↗
PubMedDate not supplied

Gender differences in patterns of dynamic cardiovascular regulation.

The purpose of this research was to examine the role of gender in hemodynamic response patterns to stress. Sixty-four male and 55 female young adults were administered a protocol of rest, mental arithmetic, video game, and anger recall interview while blood pressure, heart rate, and cardiac impedance measures were obtained. Men had higher levels of systolic blood pressure and cardiac output and greater reactivity to tasks, indexed by increases in cardiac output and diastolic blood pressure. Extreme groups of myocardial and vascular reactors were formed from cardiac output and total peripheral resistance change scores during mental arithmetic. The myocardial reactors exhibited greater sensitivity to task demands, whereas vascular reactors exhibited comparable total peripheral resistance increases to all tasks. Vascular reactors exhibited greater diastolic blood pressure reactivity than myocardial reactors. Future studies should address the predictive validity of these reactor patterns for the subsequent development of coronary heart disease.

Adult↗