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Biomedical subjects

R R Baker

Publications and source records attributed to R R Baker.

At least 91 records · Page 5Linked to original sources
PubMed1982

The role of estrogen receptor status in predicting the response of carcinoma of the breast to adjuvant chemotherapy.

This study was undertaken to determine if there was any correlation between the estrogen receptor status and the response of patients with operable carcinoma of the breast to adjuvant chemotherapy. Seventy-seven patients with metastases to the axillary lymph nodes who were receiving adjuvant chemotherapy following a modified radical mastectomy were studied. During the period of study, 12 of 34 estrogen receptor-positive tumors recurred, with a mean disease-free interval of 17.8 months, and 19 of 43 estrogen receptor-negative tumors recurred, with a disease-free interval of 15.2 months. Statistical analysis of recurrence at two years showed no difference between these two groups. Only one patient of 18 in the premenopausal group of women with estrogen receptor-positive tumors, however, had a recurrence compared with 11 of 24 patients with estrogen receptor-negative tumors. This difference was highly statistically significant, p greater than 0.0005. We have concluded that the estrogen receptor status is not a reliable indicator of response to adjuvant chemotherapy for all patients. Our data do indicate a positive correlation between response to adjuvant chemotherapy and estrogen receptor status in the premenopausal group of patients and suggest that adjuvant chemotherapy in the premenopausal group of patients may be exerting some of its effect by ovarian suppression rather than by solely cytotoxic effect on cancer cells of the breast.

Adenocarcinoma, Scirrhous↗
PubMed1982

Invasive thymomas: diagnosis and evaluation by computed tomography.

Ten cases of invasive thymoma examined by computed tomography (CT) and by conventional chest roentgenography are reviewed. In each case, CT showed at least one significant abnormality that was not disclosed by conventional techniques. Computed tomography was especially effective in detecting pleural implants above the diaphragm, pericardial tumor, mediastinal pleural involvement, and invasion of pulmonary parenchyma. Computed tomography assists in the management of patients with invasive thymoma by providing the most reliable assessment of the extent of disease. This information is useful in directing surgical intervention, providing radiotherapy treatment, evaluating treatment response, and monitoring for recurrence of disease.

Diaphragm↗
PubMed1981

A comparison of lysophosphatidylcholine acyltransferase activities in neuronal nuclei and microsomes isolated from immature rabbit cerebral cortex.

Using neuronal nuclei (N1) and microsomes (P3) isolated from cerebral cortices of 15-day-old rabbits, the activity of lysophosphatidylcholine acyltransferase (acyl CoA: 1-acyl-sn-glycerol-3-phosphorylcholine acyltransferase) was studied using palmitoyl-, oleoyl- and arachidonoyl-CoA and a pool of lysophosphatidylcholine labelled with [3H]palmitate, [3H]stearate or [3H]oleate. Generally, in the acylation of the three radioactive lysophosphatidylcholines with arachidonoyl-CoA, the N1-specific acylation activities were two to seven times those of P3. For oleoyl-coA smaller N1 : P3 specific activity ratios were found, differing significantly from unity for only the 1-palmitoyl and 1-stearoyl lysophosphatidylcholines. The N1 : P3 ratios for the two unsaturated acyl-CoA thioesters were usually found to increase as the lysophosphatidylcholine concentration was lowered from 100 to 25 microM. Thus, nuclear acylation rates, particularly with arachidonoyl-CoA, were less affected by lowering the acceptor concentration than were microsomal activities. At the high lysophosphatidylcholine concentration (100 microM), arachidonoyl-CoA was a superior substrate to oleoyl-CoA in the nuclear acylations of the 1-palmitoyl or 1-stearoyl acceptors. Such a preference was never seen for the microsomal fraction. Using oleoyl- and arachidonoyl-CoA, the nuclear enzymes also showed a greater preference for the 1-palmitoyl homologue over the 1-oleoyl homologue than did the microsomal enzymes. These results support the existence of neuronal nuclear lysophosphatidylcholine acyltransferases with different substrate preferences than shown by the microsomal fraction.

1-Acylglycerophosphocholine O-Acyltransferase↗
PubMed1981

Pathogenesis and treatment of Paget's disease of the breast.

Fifty cases of Paget's disease of the breast treated surgically at The Johns Hopkins Hospital during the past 30 years were studied. Nineteen patients had Paget's disease confined to the nipple and 31 had an associated palpable tumor. An underlying intraductal or infiltrating duct carcinoma of the breast was present in each case. In six cases, the underlying tumor was 2 cm or more from the nipple with no apparent anatomic connection to the Paget lesion, and one case was encountered in whom intradermal Paget's disease develop in the area of a congenitally absent nipple. These findings support the theory of an intradermal origin for the Paget cell. Survival rates of patients with Paget's disease and a palpable breast mass were similar to those of patients with infiltrating duct carcinoma, the presence of axillary node metastases being the most important prognostic factor. Actuarial five- and ten-year survival rates were 22% and 9.9% for patients with positive nodes. The modified radical mastectomy is recommended as primary therapy for this group of patients. In contrast, none of the patients with Paget's disease of the nipple and no evidence of a palpable breast mass developed recurrent carcinoma. A total mastectomy without an axillary node dissection is the treatment of choice in this type of patient.

Adult↗
PubMed1981

The acylation of 1-acyl-sn-glycero-3-phosphorylcholine by glial and neuronal nuclei and derived neuronal nuclear envelopes: a comparison of nuclear and microsomal membranes.

A neuronal nuclear fraction (N1), a glial nuclear fraction (N2) and a fraction containing microsomal membranes (P3) were isolated from homogenates of cerebral cortices of 15-day-old rabbits. A nuclear envelope fraction (E) was prepared from fraction N1. In comparison with the parent fraction N1, fraction E had a much lower yield of protein (0.077 mg/g cerebral cortex), a low specific DNA content, an eightfold higher specific phospholipid content (0.85 mumol phospholipid phosphate/mg protein) and a very similar phospholipid distribution profile. Using 100, 50, and 25 microM 1-acyl-sn-glycero-3-phosphorylcholine (labelled with [3H]palmitate) and 100 microM oleoyl CoA, the activity of acyl-CoA:1-acyl-sn-glycero-3-phosphorylcholine acyltransferase was studied in vitro. Fractions N1 and N2 had specific activities which were two to three times the specific activities shown for fraction P3. Fraction E was particularly enriched in this acylation activity and had specific activities which were 6 times those of fraction N1 and 11-19 times those of fraction P3. The existence of nuclear acyl-CoA:1-acyl-sn-glycero-3-phosphorylcholine acyltransferase activity was indicated as was a particularly high concentration of this enzyme within the nuclear envelope. In assays of lysolecithin-lysolecithin transacylase activities, fraction N2 (glial nuclei) showed the highest specific activities, being three to four times those of fractions N1 or P3. This transacylase activity (N2) was as high as 40% of the corresponding acyltransferase activity measured in this fraction using oleoyl CoA as acyl donor.

Animals↗
PubMed1981

Prospective clinical trial of antibiotics for pulmonary resections.

One hundred and seventy-one patients undergoing pulmonary resection were included in a prospective randomized clinical study evaluating the efficacy of prophylactic antibiotics. Eight-three patients randomly chosen received no parenteral antibiotics and 88 received a short course of cephalothin intravenously. Topical antibiotics were used in the pleural cavity and would of all patients. There were no statistically significant differences between the two groups in terms of days of postoperative fever, number of postoperative septic complications and length of postoperative stay. However, when postoperative infectious complications developed in the antibiotic group, they were often secondary to gram-negative organisms resistant to cephalothin.

Administration, Topical↗
PubMed1981

Transbronchial needle aspiration for diagnosis of lung cancer.

Thirty-two consecutive patients with mediastinal lesions suggestive of bronchogenic carcinoma underwent transbronchial needle aspiration. Eighteen of 20 patients (90 percent) with proved bronchogenic carcinoma had malignant cytology specimens or tissue fragments. Of 12 patients with normal cytology specimens, six were subsequently proved to have nonneoplastic disease. Transbronchial needle aspiration appears to offer a sensitive and specific alternative to more invasive surgical techniques used in the diagnosis of malignancies with mediastinal involvement.

Biopsy, Needle↗
PubMed1981

The correlation of estrogen and progesterone receptor levels with response to chemotherapy for advanced carcinoma of the breast.

Estrogen and progesterone receptor levels were determined simultaneously in tumor samples obtained from 105 patients who subsequently received a trial of hormonal or chemotherapy for metastatic carcinoma of the breast. Twenty-three of 33 estrogen receptor positive patients in contrast with three of 22 estrogen receptor negative patients achieved an objective response to hormonal therapy. More significantly, it was found that 12 of 16 estrogen receptor positive patients compared with only six of 34 estrogen receptor negative patients responded to combination chemotherapy. Simultaneous measurement of progesterone receptor improved the selection of tumors responsive to chemotherapy, as only four of 30 patients who were estrogen receptor negative-progesterone receptor negative achieved a response. Furthermore, the cumulative survival time of 36 months after the first recurrence of carcinoma of the breast was significantly lower in estrogen receptor negative patients receiving chemotherapy. These data indicate that patients with estrogen receptor negative carcinoma of the breast are resistant to standard hormonal and chemotherapeutic measures for metastatic disease and carry a poor prognosis.

Aged↗
PubMed1980

Goal orientation by blindfolded humans after long-distance displacement: possible involvement of a magnetic sense.

A wide range of animals are able to orient toward home when subjected to displacement-release experiments. When comparable experiments are performed on blindfolded humans, a similar ability emerges. Such goal-orientation does not result from following the complete journey on a mental map, nor is it influenced by cloud cover. Bar magnets worn on the head do seem to exert an influence.

Adult↗
PubMed1980

The incorporation of radioactive fatty acids into the phospholipids of nerve-cell-body membranes in vivo.

1. Nerve cell bodies were isolated in bulk from cerebral cortices of 15 day-old rabbits after intrathecal injections of [(3)H]plamitate, [(3)H]oleate or [(3)H]arachidonate and [(14)C]glycerol. 2. Nuclear, microsomal and two mitochondrial fractions were isolated from homogenates of the radioactively labelled nerve cell bodies by using differential and discontinuous-gradient centrifugation. 3. After 7.5min in vivo, a high percentage (>80%) of the total (3)H-labelled fatty acid radioactivity was found in the membrane fractions of the nerve cell bodies, whereas after 60min in vivo 50% of the total [(14)C]glycerol radioactivity was found in the high-speed supernatant. 4. The specific radioactivities of phosphatidylcholine, phosphatidylethanolamine and phosphatidylinositol, and the radioactivity in neutral lipid and non-esterified fatty acid fractions were determined in the four subfractions, as were the distributions of several marker enzymes and nucleates. 5. With respect of (3)H-labelled fatty acid, the phospholipids of the nuclear fraction had the highest specific radioactivities of the four subfractions. However, for [(14)C]glycerol labelling, generally the (14)C specific radioactivities for individual phospholipids were comparable in the four subfractions. This latter observation suggests transport of phospholipids synthesized de novo between membranes of the nerve cell body. 6. Double-labelling experiments demonstrated that individual phospholipids and the combined neutral lipids of the nuclear fraction had higher labelling ratios of (3)H-labelled fatty acid/[(14)C]glycerol than did the corresponding lipids of the microsomal or mitochondrial fractions. 7. On the basis of the labelling results and the marker studies, it is proposed that it is indeed the nuclei of the nuclear fraction that have these lipids highly labelled with (3)H-labelled fatty acid, and the existence of nuclear acyl transferases that are responsible for this fatty acid incorporation is suggested.

Animals↗
PubMed1980

Serum UDP-galactosyl transferase as a potential biomarker for breast carcinoma.

UDP-galactose:N-acetylglucosamine galactosyltransferase (GT) is a membrane-bound enzyme active in the biosynthesis of the carbohydrate moiety of glycoproteins and glycolipids. A soluble form of GT, present in human serum, has recently been found to be elevated in the presence of various neoplasms. In this study, GT levels were measured in randomized serum samples obtained from normal controls (group I, n = 49), patients with benign breast disease (group II, n = 46), disease controls (group III, n = 50), patients with primary breast carcinoma (group IV, n = 53), and untreated metastatic breast cancer (group V, n = 23). Although substantial serum GT elevations were observed in individual control patients with active inflammatory or metabolic diseases, the mean GT levels were significantly higher in the groups with breast carcinoma (P < 0.001, 0.001, 0.02; P < 0.001, 0.001, 0.001 for groups IV and V vs groups, 1, II, and III, respectively). Furthermore, when serum GT levels were correlated with the properative clinical stage of breast cancer, significant elevations were found in 14.3% (3/21) of stage I, 66.7% (8/12) of stage II, 78.6% (11/14) of stage III, and 96.5% (28/29) of stage IV patients. These data indicate that serum GT levels are elevated in the presence of breast carcinoma and that the enzyme elevations correlate positively with the clinical stage of disease. Serum GT may be potentially useful in the detection of recurrent breast carcinoma and as a marker of tumor response to therapy for advanced disease.

Breast Neoplasms↗
PubMed1980

The fatty acid composition of lipids of neuronal and glial nuclear fractions isolated from 15-day-old rabbit cerebral cortex.

A neuronal nuclear fraction (N1) and a glial nuclear fraction (N2) have been isolated from 15-day-old rabbit cerebral cortex using the Thompson procedure. More than 56% of the homogenate DNA was recovered in the two nuclear fractions, with N1 being the larger by about eightfold. Fractions N1 and N2 had very similar phospholipid distributions, with phosphatidylinositol being a larger component than phosphatidylserine. Fatty acid analyses demonstrated that phosphatidylethanolamine and phosphatidylinositol, individually, had similar fatty acid profiles in fractions N1 and N2, and also in nuclear and microsomal fractions derived from homogenates of nerve cell bodies isolated from cortex of 15-day-old rabbits. In contrast, the nuclear phosphatidylcholines had lower levels of palmitate and higher levels of arachidonate than did microsomal phosphatidylcholines. Molecular species analyses indicated that monoenes (41 mol%), tetraenes (20 mol%), and saturates (13 mol%, composed chiefly of palmitate) were the principal classes of N1 phosphatidylcholines, while the diacyl species of phosphatidylethanolamine of this fraction were characterized by high levels of tetraenes (44 mol%), pentaenes (17 mol%), and hexaenes + polyenes (24 mol%). The neutral glycerides of fraction N1 occurred collectively at a level of 0.05 mol/mol phospholipid. Prominent fatty acids of diacylglycerols included palmitate (31%), oleate (20%), arachidonate (14%), and stearate (13%). Triacylglycerols showed a similar pattern but with relatively high levels of linoleate (11%), while monoacylglycerols consisted almost entirely of palmitate (33%), stearate (35%), and oleate (24%).

Animals↗
PubMed1979

The isolation and lipid composition of subcellular fractions derived from neuronal perikarya isolated in bulk from rabbit cerebral cortex.

(1) Neuronal perikarya were isolated from rabbit cerebral cortex and were homogenized and separated into a number of subcellular membrane fractions using differential and discontinuous density gradient centrifugation. (2) The efficiency of homogenizing the nerve cell bodies could be greatly increased by the preliminary passage of the cell body fraction through a micropipet tip. (3) Of a number of density media, a discontinuous gradient of metrizamide gave the best resolution of the mitochondrial and lysosomal marker enzymes found in the crude mitochondrial fraction. This yielded a purified mitochondrial fraction and several lighter membrane fractions. (4) The lighter membrane fractions in metrizamide contained a degree of mitochondrial contamination which could be removed by a second gradient spin on 1.2 M sucrose, producing a second mitochondrial fraction and two light membrane fractions. (5) Based on marker analyses, fractions enriched in nuclei, mitochondria, microsomes and plasma membrane/lysosomes were produced. (6) The two mitochondrial fractions showed the highest, and the nuclear fraction the lowest specific phospholipid content. Cholesterol: phospholipid molar ratios showed a gradient of values from a low (0.2) for the mitochondria and nuclei to an intermediate value (0.4) for the microsomes to a high (0.6) for the light membrane fractions. (7) Phospholipid distributions indicated that for the nuclear and mitochondrial fractions phosphatidylinositol was more abundant than sphingomyelin or phosphatidylserine, while for the microsomes and the two light membrane fractions these three phospholipids were present in almost equal amounts.

Acetylglucosaminidase↗
PubMed1979

Selective nonoperative management of contained intrathoracic esophageal disruptions.

Eight patients with intrathoracic esophageal disruptions were managed nonoperatively and without pleural drainage. Criteria for nonoperative treatment included the following: disruption contained in the mediastinum or between the mediastinum and visceral lung pleura; drainage of the cavity back into the esophagus; minimal symptoms; and minimal signs of clinical sepsis. Cause of the esophageal perforation was pneumostatic dilatation (1 patient), vomiting (2), and a leak following esophageal operation (5). Antibiotics were administered intravenously to all patients; hyperalimentation was accomplished intravenously in 5, and nasogastric suction was used in only 1. The cavities contracted and the esophageal leaks sealed in all instances. Time before oral intake was resumed ranged from 7 to 38 days (average, 18 days). Days until discharge ranged from 15 to 52 days (average, 28 days).

Adult↗