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Biomedical subjects

L C Williams

Publications and source records attributed to L C Williams.

At least 37 records · Page 2Linked to original sources
PubMed1989

Pulmonary artery banding: analysis of a 25-year experience.

A 25-year experience (May 1962 through April 1987) with pulmonary artery banding in 183 patients was reviewed and analyzed. Pulmonary artery banding was performed in a heterogeneous group of patients aged two days to 60 months (median, 10 weeks; mean, 21.8 weeks) and weighing 1.4 to 13.8 kg (mean, 4.2 kg). Diagnosis was ventricular septal defect in 76 (41.5%) and atrioventricular communis in 41 (22.4%). Pulmonary artery banding was also used in patients with d-transposition of the great vessels with ventricular septal defect, double-outlet right ventricle, univentricular heart, tricuspid atresia, and truncus arteriosus. Early death occurred in 39 of 175 patients who underwent pulmonary artery banding at Ochsner Foundation Hospital (22.3%). Definitive operation has been performed in 37 of the patients who underwent pulmonary artery banding since 1979 with excellent outcome in 32 (86.5%). Pulmonary artery banding is a useful palliative procedure for a diverse group of patients with congenital cardiac anomalies and unrestricted pulmonary blood flow. With improved results of primary repair of intracardiac anomalies in small infants, however, pulmonary artery banding should be reserved for severely ill patients with complex lesions not amenable to early definitive correction. Currently, pulmonary artery banding is indicated in patients with excessive pulmonary blood flow and single ventricle or tricuspid atresia. Pulmonary artery banding is also appropriate in certain patients with atrioventricular communis and in patients with muscular or multiple ventricular septal defects. Pulmonary artery banding is an option in patients with ventricular septal defect and coarctation of the aorta.

Constriction↗
PubMed1989

Creation of H-2 class I epitopes using synthetic peptides: recognition by alloreactive cytotoxic T lymphocytes.

A major role that cytotoxic T lymphocytes (CTLs) play in the immune response is the specific destruction of viral-infected cells and tissue from foreign grafts. Class I molecules encoded within the major histocompatibility complex are the target structures for these CTLs. Recently, viral-restricted CTLs have been shown to recognize viral peptides in association with class I molecules, while several studies with cloned alloreactive CTLs have indicated that these T cells can recognize class I-derived peptides in association with class I molecules. Together, these observations suggest that peptide binding is an important function of class I molecules. In this paper, we show that the recognition of a particular class I molecule by a bulk population of alloreactive CTLs can be altered by incubating with it a peptide derived from another class I molecule. Specifically, we used the hybrid D/Ldm1 molecule as a target structure together with the peptide Ld61-85, and we have shown that their associative recognition by Ld-specific CTLs depends on sequence and configuration of the peptide and is specific for Ld using a cold-target inhibition assay. Our results are discussed in light of three possible models for the target structure(s) that can be recognized by alloreactive CTLs and in terms of the role peptides may play during allorecognition.

Amino Acid Sequence↗
PubMed1989

Antibodies against platelet glycosphingolipids: detection in serum by quantitative HPTLC-autoradiography and association with autoimmune and alloimmune processes.

In order to assess the importance of glycosphingolipids (GSL) in the immunology of the platelet, serum antibody binding to immobilized, purified platelet GSLs have been quantitatively measured via high-performance thin-layer chromatography (HPTLC), 125I-radio-immunolabeling, autoradiography, and densitometry. Thirteen neutral GSL bands were detected at Rf.03 through .64 (CHCl3-CH3OH-H2O, 65:25:4) after extraction and chromatography (DEAE-Sephadex and Bio-sil A). Both IgM and IgG serum antibody binding was determined for 50 subjects from four groups: normal blood donors (NBD, n = 18); leukemia patients with nonimmune thrombocytopenia (NIT, n = 10); patients with systemic lupus erythematosus (SLE, n = 10); and patients with chronic autoimmune thrombocytopenia (CATP, n = 12). The ABO typing of these 50 subjects also allowed correlation of serum antibody binding with A blood group antigen expression. These studies reveal: (1) anti-GSL binding at band .06 is associated with blood group A alloantigen expression for both IgG and IgM (P less than .0001) antibodies; (2) binding at bands .17, .27, and/or .46 is associated with general autoimmunity (SLE and CATP) for IgM (P less than .0001); (3) binding at bands .35 and/or .38 is associated with platelet-specific autoimmunity (CATP) for IgG and/or IgM (P less than .005); and (4) binding at bands .03, .20, .23, and/or .43 is frequently observed for sera from all groups. The platelet specificity of bands .35 and .38 was confirmed by comparative studies with human intestinal smooth muscle GSLs. Quantitation of the intensity of CATP-associated anti-GSL binding (86 +/- 88 mm2) is comparable to anti-A alloantigen binding (57 +/- 52 mm2). Two of the GSL bands associated with SLE and CATP appear to be the long-chain fatty-acyl forms of globotriaosyl ceramide (.27) and globotetraosyl ceramide (.17), which are the Pk and P blood group antigens, respectively. These studies indicate that neutral GSLs may be important antigens in both autoimmune and alloimmune processes involving the blood platelet.

Autoantibodies↗
PubMed1986

Milk alkali syndrome following over-the-counter antacid self-medication.

Four patients with mild, asymptomatic chronic renal failure became severely hypercalcaemic while taking over-the-counter antacids with daily calcium loads of only 4-8 g. Renal impairment carries an increased liability to this syndrome. Persistent elevation of serum parathyroid hormone levels led to parathyroid exploration in two of the cases, and normal glands were found. In retrospect the hormone levels were appropriate to the degree of renal impairment. Over-the-counter antacid preparations should carry dosage warnings to avoid the possibility of hypercalcaemia.

Aged↗
PubMed1985

Technique and experience with azygos patch modified Blalock-Taussig anastomosis for congenital cyanotic heart disease.

Seventeen patients 1 day to 28 months old with congenital cyanotic heart disease underwent a modification of the Blalock-Taussig shunt. Eight were newborn infants weighing 2.6 to 4.8 kg. All infants had complex congenital heart defects that were not considered amenable to early correction. There were no early deaths and no shunt failures. Postoperative complications were restricted to prolonged intubation in 2 patients and a subcutaneous wound infection in a 14-day-old infant. Follow-up from 1 to 31 months revealed minimal cyanosis, stable hemoglobin levels, and good shunt murmurs, and there have been no upper extremity complications. There were 2 late deaths; 1 (the oldest patient) was related to medication, and the second resulted from small bowel necrosis. The concept of the azygos vein patch modified Blalock-Taussig shunt involves two factors: (1) mobilizing as much length as possible of the subclavian artery in spite of its distal small size to allow for a tension-free shunt to prevent tension on the anastomosis as growth occurs, and (2) enlarging the subclavian artery distal to the vertebral artery origin with an autologous azygos patch. During performance of a standard Blalock-Taussig shunt, a longitudinal incision is made through the pulmonary artery across the anastomosis into the upper subclavian artery. The appropriate length of harvested azygos vein is used as a patch angioplasty across the shunt. A tension-free shunt with a patulous distal portion is achieved. Pulmonary overcirculation is avoided by the limiting size of the proximal subclavian artery. Temporary occlusion of the shunt at operation resulted in an increased mean blood pressure from 6 to 18% in all infants.(ABSTRACT TRUNCATED AT 250 WORDS)

Arteriovenous Anastomosis↗
PubMed1982

Psychosocial problems in chronically ill children: physician concern, parent satisfaction, and the validity of medical records.

This study concerns the psychosocial aspects of treatment for chronically ill children. The English-speaking parents of 44 children 5-13 years of age being seen at five specialty clinics at a large county hospital in Los Angeles, and their attending physicians, were the subjects in this study. The parents were interviewed concerning their expectations for the current visit, and the doctor-patient interaction was tape-recorded. Identical categories of information were abstracted from the tape recording and from a chart review of the patients' medical records. Although parents expected 76% of the psychosocial aspects of care to be covered by the doctor, only one fourth were actually discussed in the visit. These unfulfilled expectations were associated with lower satisfaction with medical care received (r = .47, p less than 0.01). Finally, while doctors recorded about 80% of discussions of symptoms and physical examinations in the patient's medical record, they recorded only 25% of discussion of psychosocial problems.

Adolescent↗
PubMed1982

Plasma exchange in Goodpasture's syndrome.

The clinical course and levels of anti-glomerular basement membrane (GBM) antibody were compared in 20 patients with Goodpasture's syndrome treated with plasma exchange and immunosuppression (8 patients), immunosuppression alone (4 patients) or no specific therapy (8 patients). There was a more rapid fall in the level of anti-GBM antibody and pulmonary hemorrhage was less protracted in the 8 patients treated with plasma exchange and immunosuppression. In this group, 1 patient who presented with severe renal failure showed a marked improvement of renal function and there was no progression of disease in the 4 with milder renal involvement. 2 of the 4 patients treated with immunosuppression alone, and only 2 of the 8 patients who received no specific therapy, maintained normal renal function. In the group which received no specific therapy, 1 of the 6 patients who progressed to renal failure had mild renal involvement initially. There was a significant correlation between the level of anti-GBM antibody and the severity of the morphological changes seen at renal biopsy but not between the level of anti-GBM antibody and the severity of lung hemorrhage. The course and outcome of the disease in those patients not treated, or treated with immunosuppression alone, was better than that described in early reports of this disease, while those patients with plasma exchange and immunosuppression fared even better. An adequately stratified controlled trial of immunosuppression and plasma exchange versus immunosuppression alone is in order.

Adolescent↗
PubMed1981

The amino acid sequence of the beta subunit of allophycocyanin.

The complete amino acid sequence of the beta subunit of Anabaena variabilis allophycocyanin is: H2N-Ala-Gln-Asp-Ala-Ile-Thr-Ala-Val-Ile-Asn-Ser-Ala-Asp-Val-Gln-Gly-Lys-Tyr-Leu-Asp-Thr-Ala-Ala-Leu-Glu-Lys-Leu-Lys-Ala-Tyr-Phe-Ser-Thr-Gly-Glu-Leu-Arg-Val-Arg-Ala-Ala-Thr-Thr-Ile-Ser-Ala-Asn-Ala-Ala-Ala-Ile-Val-Lys-Glu-Ala-Val-Ala-Lys-Ser-Leu-Leu-Tyr-Ser-Asp-Ile-Thr-Arg-Pro-Gly-Gly-Asn-Met-Tyr-Thr-Thr-Arg-Arg-Tyr-Ala-Ala-Cys-Ile-Arg-Asp-Leu-Asp-Tyr-Tyr-Leu-Arg-Tyr-Ala-Thr-Tyr-Ala-Met-Leu-Ala-Gly-Asp-Pro-Ser-Ile-Leu-Asp-Glu-Arg-Val-Leu-Asn-Gly-Leu-Lys-Glu-Thr-Tyr-Asn-Ser-Leu-Gly-Val-Pro-Val-Gly-Ala-Thr-Val-Gln-Ala-Ile-Gln-Ala-Ile-Lys-Glu-Val-Thr-Ala-Ser-Leu-Val-Gly-Ala-Asp-Ala-Gly-Lys-Glu-Met-Gly-Ile-Tyr-Leu-Asp-Tyr-Ile-Ser-Ser-Gly-Leu-Ser-COOH Phycocyanobilin is attached though a thioether linkage to cysteinyl residue 81, indicated by an asterisk. Comparison of this sequence with those of C-phycocyanins shows that there are 60 identities between corresponding subunits of these two biliproteins. Of the region between residues 79 and 120, 29 residues are identical in the beta subunits of allophycocyanin and phycocyanin. The character of all 10 charged residues in this region of the beta subunit sequences is completely conserved.

Amino Acid Sequence↗
PubMed1981

A histone-like protein (HTa) from Thermoplasma acidophilum. II. Complete amino acid sequence.

The complete amino acid sequence of the DNA-binding histone-like protein (Hta) from Thermoplasma acidophilum has been established by sequence studies directly on the protein and on tryptic, chymotryptic, and thermolysin peptides derived from the protein. The sequence of the 89-residue form of HTa is: H2N-Val-Gly-Ile-Ser-Glu-Leu-Ser-Lys-Glu-Val-Ala-Lys-Lys-Ala-Asn-Thr-Thr-Gln-Lys -Val-Ala-Arg-Thr-Val-Ile-Lys-Ser-Phe-Leu-Asp-Glu-Ile-Val-Ser-Glu-Ala-Asn-Gly-Gl y-Gln-Lys-Ile-Asn-Leu-Ala-Gly-Phe-Gly-Ile-Phe-Glu-Arg-Arg-Thr-Gln-Gly-Pro-Arg-L ys-Ala-Arg-Asn-Pro-Gln-Thr-Lys-Lys-Val-Ile-Glu-Val-Pro-Ser-Lys-Lys-Lys-Phe-Val- Phe-Arg-Ala-Ser-Ser-Lys-Ile-Lys-Tyr-Gln-Gln-COOH The molecular weight calculated from the sequence is 9,934. Another form of HTa probably differs only by the presence of an additional residue (methionine) at the NH2 terminus (the calculated molecular weight of this form is 10,065). HTa resembles eukaryotic histones in several ways, including some sequence homology, HTa also shows sequence homology with the Escherichia coli DNA-binding proteins NS1 (or HU-1) and NS2 (or HU-2).

Amino Acid Sequence↗
PubMed1981

The effects of two different dosage regimens of sulphinpyrazone on platelet function ex vivo and blood chemistry in man.

When sulphinpyrazone (either 200 mg q.d.s. for 7 days or 400 mg b.d.s. for 5 days) was administered to human volunteers, inhibition of platelet function was observed ex vivo. The inhibitory effect was measured by the increase in the concentration of sodium arachidonate required to cause platelet aggregation and a decrease in the biosynthesis by the platelets of malondialdehyde from added sodium arachidonate. ADP-induced primary platelet aggregation was statistically significantly inhibited only on 1 day of the two studies. The inhibitory effect did not correlate with the plasma concentrations of unchanged sulphinpyrazone nor with its sulphone metabolite but correlated with the plasma concentration of the thioether metabolite (r = 0.577, p less than 0.001). Platelet count, plasma fibrinogen, beta-thromboglobulin, urea and creatinine concentrations were not changed by the drug but there was a clinically insignificant increase in bleeding time in all but one subject.

Bleeding Time↗
PubMed1980

Platelet protection and heparin sparing with prostacyclin during regular dialysis therapy.

When prostacyclin (5 ng kg-1 min-1) was given during dialysis it enhanced the biological activity of heparin and prevented the activation and consumption of platelets. No adverse effects were observed. The reduction in heparin requirements produced by prostacyclin should make dialysis, safer, particularly for patients at risk of bleeding, while preserving the biocompatibility of the dialysis circuit. It remains to be established whether prevention of platelet activation will confer long-term benefit by inhibiting the prothrombotic state induced by haemodialysis, thereby reducing the risk of atherosclerosis in uraemic patients.

Adult↗
PubMed1980

Risks and benefits of bilateral nephrectomy: an analysis of 134 cases.

In a retrospective survey of 134 patients undergoing bilateral nephrectomy from 1969 to 1980 it was found that the commonest indications were hypertension (60%) and infection/reflux (22%). Operation in hypertensive dialysis patients was followed by a fall in blood pressure in 70% (SE 9%) at one and 3 months while normotensive patients having their kidneys out for other reasons had a 47% (SE 11%) incidence of hypertension at one month and 7 out of 10 were still hypertensive at 3 months. When operation was performed in transplanted patients, 7 of 10 hypertensives had a fall in pressure, one of 6 normotensive persons had an increase, an use of antihypertensive drugs fell from 13/16 to 4 of 16 patients. The mortality was 10.4% (SE 2.6%) overall, the mortality of operations which included an unplanned splenectomy was significantly higher. There were 34 other complications in 25 patients. Complications, but not deaths, were more frequent in operations performed in dialysis patients rather than at the same time as, or after, a transplant. Over 12 years the ratio of bilateral nephrectomy to renal transplant operations has fallen from 8% (1969-1971) to 18% (1978 to present). The decrease is partly due to a fall in the number of operations for hypertension in dialysis patients and may be related to the appearance of beta-blocker and new vasodilator drugs.

Blood Pressure↗