PubMed Health⌕ Search

Biomedical subjects

A R Baker

Publications and source records attributed to A R Baker.

At least 37 records · Page 2Linked to original sources
PubMed1994

Treatment with intralesional granulocyte instillations and interferon-gamma for a patient with chronic granulomatous disease and multiple hepatic abscesses.

We present the case of a 16-year-old girl with p22-deficient chronic granulomatous disease in whom multiple hepatic abscesses secondary to Staphylococcus aureus infection developed. Infection persisted despite extensive surgery and aggressive antibiotic therapy. Conventional intravenous granulocyte transfusions were not tolerated because of the development of alloantibodies to HLA. Treatment with interferon-gamma and intralesional granulocyte infusions was associated with dramatic clinical and radiographic improvement. No morbidity was associated with this therapy. To our knowledge, this is the first report of treatment with intralesional granulocyte instillations. Intralesional granulocyte instillation in association with interferon-gamma administration may result in clinical improvement in the conditions of patients with chronic granulomatous disease and hepatic abscesses for whom conventional therapy has failed.

Adolescent↗
PubMed1993

Surgical management of pulmonary infections in chronic granulomatous disease of childhood.

Chronic granulomatous disease of childhood is an inheritable disorder of phagocytic cell respiratory burst resulting in recurrent, life-threatening, catalase-positive infections. The lung is the most common site of infection, and pulmonary disease is the primary cause of death in greater than 50% of children with chronic granulomatous disease. Still, the role of surgery in management of this disease remains undefined. Between 1974 and 1990, 19 patients with chronic granulomatous disease required 31 thoracic interventions at our institution. Patients ranged in age from 2.5 to 27 years (mean age, 15 years). Seventeen of 19 patients (89%) had had previous pulmonary infections. Patients presented as toxic (temperature > 38.5 degrees C, chest pain, and cough) in 22 instances before the 31 procedures. Aggressive surgical intervention for diagnosis and extirpation of localized infections was undertaken with lobectomy/pneumonectomy with or without other procedures (5), bisegmentectomy (2), segmentectomy with or without other procedures (5), or wedge with or without other procedures (13). In five instances, an empyema was drained; a chest tube for a sterile collection was placed in one instance. There was one intraoperative death, and 3 patients died 22 to 600 days postoperatively with overwhelming sepsis. The mean hospitalization was 101 days (range, 24 to 600 days). Wound complications occurred in 5 patients, requiring 17 separate anesthetic debridements. A change in therapy was dictated by the results of the procedure in 23 of 31 instances (74%). Thoracic surgeons must be aware of this rare cause of immunosuppression in these children and, due to the unusual nature of the pulmonary infections, should follow an aggressive approach in their diagnosis and management.

Adolescent↗
PubMed1992

Osteoblast-specific expression of growth hormone stimulates bone growth in transgenic mice.

Growth hormone (GH) is an important regulator of postnatal growth, acting on a wide variety of target tissues. Here, we show that local production of GH in osteoblasts is able to stimulate bone growth directly without significant systemic effects. Mice were made transgenic by microinjection of an osteocalcin-human GH (osteocalcin-hGH) gene construct in which approximately 1,800 bp of the rat osteocalcin promoter was fused to the hGH gene. Five lines of transgenic mice, each with measurable amounts of serum hGH (ranging from 1 to 1,000 ng/ml), were analyzed. Northern (RNA) blot hybridization showed that the hGH transcript was detectable only in the bone. Further characterization of hGH mRNA distribution by in situ hybridization revealed that in neonates the most intense signal was found in periosteal osteoblasts, while in adults, trabecular and endosteal osteoblasts were favored. In one transgenic line (992-1), hGH was expressed at a much lower level and had minimal systemic effects; however, the local concentrations of hGH in bone were sufficient to stimulate bone growth in these animals.

Animals↗
PubMed1992

A prospective study of the value of core needle biopsy and fine needle aspiration in the diagnosis of soft tissue masses.

We prospectively sampled 38 large soft tissue masses in 37 patients with both core needle biopsy (CNBX) and fine-needle aspiration (FNA) to determine the diagnostic utility of these biopsy methods. In 27 cases the histologic diagnosis made from the resected specimen was compared with the diagnosis based on the biopsy. CNBX correctly identified 16 of 16 malignant sarcomas and 10 of 11 benign masses (one was indeterminate). The grade of the sarcoma was determined correctly in every case. There were no false malignant or false benign CNBX diagnoses. FNA correctly classified 12 of 14 malignant sarcomas and four of 11 benign lesions. Diagnoses based on FNA were limited by a high proportion of samples, especially from benign lesions, that were inadequate for definitive diagnosis and by an inability to grade many malignant sarcomas. There were no significant complications resulting from the biopsies. We conclude that CNBX is a highly accurate, easily performed method for the diagnosis of large soft tissue masses that can be accomplished with minimal morbidity.

Adolescent↗
PubMed1991

The prognosis of melanoma patients with metastases to two or more lymph node areas.

The prognosis of melanoma patients who present with metastatic involvement of two or more noncontiguous lymph node regions before the detection of extranodal metastases has not been previously reported. We identified 21 patients with metastatic melanoma in at least two nodal basins in a review of 175 patients with melanoma undergoing lymphadenectomy at the National Cancer Institute. The median survival time of these patients was 46 months, with 55%, 27%, and 17% of the patients alive 2, 5, and 10 years, respectively, after the second lymphadenectomy. Because the prognosis of melanoma patients with metastases to two or more regional nodal areas appears equivalent to that of patients with metastatic involvement of only one regional node site, lymphadenectomy of the involved groups should be performed with therapeutically curative intent.

Adolescent↗
PubMed1991

Calcium dependent and independent endothelin-1-induced contraction of human omentum vessels.

Endothelin-1, an endothelium derived vasoconstrictor peptide, induced concentration-dependent contraction of isolated human omental resistance arteries. Pre-treatment with the calcium antagonist nicardipine or calcium depletion caused a significant reduction but did not abolish the contractile response. However, when calcium depletion was combined with pretreatment with the protein kinase C inhibitor (H7), endothelin-1 failed to produce a contraction. This study shows that a large component of endothelin-1 contraction is calcium-dependent, involving activation of dihydropyridine-sensitive voltage-dependent calcium channels but in addition there is a calcium-independent component produced by protein kinase C activation.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1989

Vasoconstrictor actions of endothelin-1 in human resistance vessels.

The contractile response to endothelin-1 was studied in isolated human resistance vessels in the presence and absence of extracellular calcium. Endothelin-1 was 1000-fold more potent than noradrenaline, with an ED50 of 6.5 +/- 1.26 x 10(-9) mol/l compared with 2.1 +/- 0.7 x 10(-6) mol/l. Calcium depletion by repeated stimulation with noradrenaline in a calcium-free medium attenuated but did not prevent a sustained contraction in response to endothelin-1 (30% of control). On re-adding calcium to the bath a full contraction immediately occurred. These experiments suggest that an endothelin-1-induced contraction is largely dependent on the presence of extracellular calcium, but a partial contraction can be induced in a calcium-free medium and this may be dependent on mobilization of intracellular calcium from a store not affected by repeated noradrenaline stimulation.

Adult↗
PubMed1988

Cloning and expression of full-length cDNA encoding human vitamin D receptor.

Complementary DNA clones encoding the human vitamin D receptor have been isolated from human intestine and T47D cell cDNA libraries. The nucleotide sequence of the 4605-base pair (bp) cDNA includes a noncoding leader sequence of 115 bp, a 1281-bp open reading frame, and 3209 bp of 3' noncoding sequence. Two polyadenylylation signals, AATAAA, are present 25 and 70 bp upstream of the poly(A) tail, respectively. RNA blot hybridization indicates a single mRNA species of approximately equal to 4600 bp. Transfection of the cloned sequences into COS-1 cells results in the production of a single receptor species indistinguishable from the native receptor. Sequence comparisons demonstrate that the vitamin D receptor belongs to the steroid-receptor gene family and is closest in size and sequence to another member of this family, the thyroid hormone receptor.

Amino Acid Sequence↗
PubMed1988

Adjuvant chemotherapy for patients with high-grade soft-tissue sarcomas of the extremity.

We have previously reported the results of a randomized trial that demonstrated the survival benefit of adjuvant chemotherapy in the treatment of patients with high-grade extremity sarcomas compared with no chemotherapy. This regimen included doxorubicin, cyclophosphamide, and methotrexate. This report updates and extends our experience. The median follow-up of this trial is now 7.1 years and reveals a 5-year disease-free survival of 75% and 54% for chemotherapy and no chemotherapy groups, respectively (two-sided P [P2] = .037). The 5-year overall survival for patients in this trial was 83% and 60% for the chemotherapy and no chemotherapy groups, respectively, with a trend towards improved survival in the chemotherapy arm (P2 = .124). Because of doxorubicin-induced cardiomyopathy we performed a subsequent randomized trial comparing this high-dose regimen to reduced cumulative doses of doxorubicin and cyclophosphamide without methotrexate. Eighty-eight patients were entered into this trial which has a median follow-up of 4.4 years. The 5-year disease-free and overall survival for patients treated with the reduced doses of chemotherapy was 72% and 75%, respectively, and was not significantly different from the high-dose regimen. No patients developed congestive heart failure on this study. We conclude that adjuvant chemotherapy improves disease-free survival in patients with extremity soft-tissue sarcomas. The overall survival advantage in patients receiving adjuvant chemotherapy in our initial randomized high-dose chemotherapy trial has diminished though it continues to favor the chemotherapy group. A reduced-dose chemotherapy regimen was found to be comparable to the high-dose regimen.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1987

Symptomatic submucosal lipoma of the large bowel.

Symptomatic large bowel lipomata may be of considerable size and usually present in middle age with symptoms of obstruction or bleeding. Although they are rare, their recognition is important so that patients may be spared unnecessary colonic resection for a presumptive malignant diagnosis. Colonoscopic removal may often be feasible. Six cases are reported together with a review of the literature emphasizing the characteristic features.

Adult↗