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Biomedical subjects

D E Johnson

Publications and source records attributed to D E Johnson.

At least 289 records · Page 16Linked to original sources
PubMed1992

Maintenance energy requirement of llamas.

Five castrated male llamas (mean body weight, 94 kg) were studied in an energy balance trial to determine maintenance energy requirement of llamas. Llamas were fed a 50% oat hay-50% pelleted concentrate diet (2.43 Mcal of metabolizable energy/kg of diet dry matter) at approximately 1.6% of body weight (BW). An 8-day total collection digestion trial was used to determine fecal and urine energy losses. Heat production and methane emissions were determined via indirect respiration calorimetry measurements on each llama fed at the same level of intake as during the digestion trial and subsequently on days 3 and 4 of a period of nonfeeding. Fecal, urine, and methane energy losses of the llamas fed near-maintenance intake were 32.5, 3.5, and 7.1% of gross energy intake, respectively. The postabsorptive metabolic rate, commonly called nonfed (fasting) heat production, was 59.3 kcal/BW0.75. Using a linear relation between postabsorptive and maintenance energy requirement and efficiency of energy use below maintenance of 0.702, metabolizable energy requirement at maintenance was determined to be 84.5 kcal/BW0.75.

Animal Feed↗
PubMed1992

Immunocytochemical staining of fine-needle aspiration biopsies of the liver as a diagnostic tool for hepatocellular carcinoma.

Fine-needle aspiration biopsy (FNAB) under ultrasonographic or computerized tomographic guidance is a useful diagnostic procedure for hepatic neoplasms. However, cytologic criteria alone may not allow for the distinction of hepatocellular carcinomas (HCC) from cholangiocarcinomas (CC) and metastatic adenocarcinomas (MA). In an effort to refine the FNAB diagnosis of hepatic malignancies, a panel of immunocytochemical stains was applied to aspiration specimens from primary and metastatic carcinomas in the liver. Anticytokeratin antibodies with different specificities (Cam 5.2 and AE1) were used in conjunction with antibodies to carcinoembryonic antigen (CEA), alpha-fetoprotein (AFP), and alpha-1-antitrypsin (AAT). All HCC, CC, and MA were immunoreactive with the antikeratin antibody Cam 5.2. However, only three (15%) HCC were positive with AE1, in contrast to 100% of CC and MA. Antibodies to CEA and AFP were also helpful diagnostic aids, especially for the three HCC that were immunoreactive with AE1. Canalicular staining for CEA was present in 47% of HCC, but in none of the CC or MA. AFP positivity occurred in 45% of HCC, but only one CC and none of the MA. AAT was not a useful marker for HCC due to low sensitivity and specificity. Immunocytochemistry is an effective adjunct to the cytodiagnosis of malignant liver tumors sampled by FNAB.

Biopsy, Needle↗
PubMed1992

Functional innervation of pig tracheal smooth muscle: neural and non-neural mechanisms of relaxation.

In pig tracheal smooth muscle (TSM), the isometric tension responses to electrical field stimulation (EFS) were compared to exogenous peptides, vasoactive intestinal polypeptide (VIP) and calcitonin gene-related peptide (CGRP), as well as to the nicotinic agonist dimethylphenyl piperazinium chloride (DMPP). The objectives of this study were to understand the mechanisms of nonadrenergic, noncholinergic relaxations of pig TSM and identify some putative candidate substances mediating the neural inhibitory response. In strips of TSM obtained from 6- to 12-week-old pigs set up in vitro in organ baths in Kreb's solution, EFS resulted in frequency-dependent contractions that were abolished by 1 microM atropine or 0.1 microM tetrodotoxin (TTX). Addition of DMPP (20-100 microM) resulted in a transient, atropine-sensitive contraction, which quickly desensitized. EFS failed to elicit any further contractions, but the tissues responded to carbachol. In tissues exposed to DMPP and contracted with carbachol, EFS elicited frequency-dependent relaxations that were unaffected by 1 microM propranolol, abolished by TTX and partially inhibited by omega-conotoxin. At the peak of carbachol-induced contraction, addition of DMPP resulted in rapid relaxation reversing spontaneously to base line, with no significant relaxation to further addition of DMPP. DMPP-induced relaxations were unaffected by TTX or omega-conotoxin. These tissues readily relaxed to 10(-8) M VIP. In carbachol precontracted tissues, VIP elicited concentration-dependent relaxations that quickly desensitized. However, these tissues readily relaxed to DMPP. CGRP produced only weak relaxations.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Bioelectrical impedance and zoometry for body composition analysis in domestic cats.

Zoometric measurements and bioelectrical impedance analysis were evaluated as methods of body composition determination in healthy cats. Zoometric and impedance measurements were taken on 22 anesthetized adult cats of various ages, genders, breeds, and body weights. The cats were then euthanatized. The bodies were processed through a tissue homogenizer and free-catch specimens were taken, freeze-dried, and analyzed for total body water, protein, fat, potassium, and ash content. Stepwise regression analysis was implemented to identify statistically significant relationships between the chemically determined dependent variables (total body water, protein, potassium, fat-free mass, fat mass, and percent body fat) and the zoometric measurements, with or without bioelectrical impedance analysis. Statistical analysis revealed high correlations between the dependent variables and the corresponding predicted values of those variables. Body weight alone was a poor predictor of body composition in these cats. On the basis of these findings, we suggest that zoometric and bioelectrical impedance measurements may serve as practical, noninvasive, simple, and accurate methods for estimating body composition in domestic cats.

Animals↗
PubMed1991

Medical evaluation of internationally adopted children.

BACKGROUND: Despite many reports of medical illness in children adopted from abroad, there are currently no accepted guidelines for medical evaluation of this population. METHODS: Two hundred ninety-three children adopted from 15 countries (mean age, 14.0 months; 55 percent girls) were evaluated by history taking, physical examination, and screening tests for hepatitis B virus (HBV), human immunodeficiency virus type 1, tuberculin reactivity, intestinal parasites, syphilis, excretion of cytomegalovirus, renal disease, and anemia. All but four were seen within one month of their arrival in the United States. RESULTS: Fifty-seven percent of the children (168 of 293) were found to have at least one important medical condition. Eighty-one percent of the diagnoses were established by screening test, rather than by history taking or physical examination. Infectious diseases made up the majority of the medical conditions (73 percent). Serologic testing for hepatitis B surface antigen was positive in 5 percent of the children. Characteristics associated with the acquisition of HBV infection included arrival within the first three years of the study (P = 0.017), Asian origin (P = 0.011), and receipt of a blood transfusion abroad (P = 0.008). Ten children (3 percent) had positive Mantoux skin tests, and four of these had active pulmonary tuberculosis. Tuberculin reactivity was significantly associated with older age (P less than 0.001) and lower weight (P = 0.037). Intestinal parasites were isolated from 14 percent of the international adoptees. Non-Korean adoptees were 16 times more likely to be harboring at least one intestinal parasite than were Korean adoptees (P = 0.005). CONCLUSIONS: Directed screening tests should be a routine component of the medical evaluation of all children adopted from abroad, regardless of age, sex, or country of origin.

Adoption↗
PubMed1991

Primary adenocarcinoma of the urinary bladder. A clinicopathologic analysis of 72 cases.

Adenocarcinomas account for approximately 2% of primary epithelial malignancies of the urinary bladder. The clinicopathologic features of 72 cases treated at one institution are reported; 22 cases were evaluated immunohistochemically. Twenty-four tumors were urachal and 48 nonurachal. The cases were analyzed according to their stage at presentation, histologic type, and mucin staining; they were tested immunohistochemically to determine their reaction to carcinoembryonic antigen, Leu-M1, prostate-specific antigen, and prostatic acid phosphatase. Tumor stage was a highly significant predictor of outcome (P = 0.001). Nonurachal tumors tended to have a worse outcome than urachal, but the difference was not statistically significant (P = 0.07). Histologic type was not a significant predictor of outcome (P = 0.10). For adenocarcinoma of the urinary bladder, stage was the most significant predictive factor; separating urachal from nonurachal tumors was important, but mucin histochemistry and immunohistochemistry did not help in this distinction. On occasion, a few tumors may react with some polyclonal antibodies to prostate-specific antigen; thus these results must be interpreted with caution. In these instances, the possibility of using highly sensitive and specific monoclonal antibodies such as the one employed in this study should be considered.

Adenocarcinoma↗
PubMed1991

Isolation of an additional member of the fibroblast growth factor receptor family, FGFR-3.

The fibroblast growth factors are a family of polypeptide growth factors involved in a variety of activities including mitogenesis, angiogenesis, and wound healing. Fibroblast growth factor receptors (FGFRs) have previously been identified in chicken, mouse, and human and have been shown to contain an extracellular domain with either two or three immunoglobulin-like domains, a transmembrane domain, and a cytoplasmic tyrosine kinase domain. We have isolated a human cDNA for another tyrosine kinase receptor that is highly homologous to the previously described FGFR. Expression of this receptor cDNA in COS cells directs the expression of a 125-kDa glycoprotein. We demonstrate that this cDNA encodes a biologically active receptor by showing that human acidic and basic fibroblast growth factors activate this receptor as measured by 45Ca2+ efflux assays. These data establish the existence of an additional member of the FGFR family that we have named FGFR-3.

Amino Acid Sequence↗
PubMed1991

A QSAR study of the toxicity of amines to the fathead minnow.

Simple and multiple linear regressions were applied to the development of fish toxicity QSAR models for the 96-h LC50 to the fathead minnow, Pimephales promelas. The data on unbranched saturated primary alkylamines as well as the complete data set were well-fitted to linear QSAR models using log P or the valence first-order connectivity index (1XV) as descriptors. Although adding data on other subclasses of amines in this data set yield acceptable QSARs, only the tertiary amine subclass provided a poor fit with both of these descriptors. The amines include both acyclic and cyclic derivatives, either with no additional functional groups, or with the hydroxyl, keto, methoxy, and propargyl moieties. The molecular mechanism for fish toxicity of these amines as well as the outliers in the study were investigated. Based upon the calculated log P value of -1.40, tripropargylamine has an apparent excess toxicity of 84 times; in contrast, the measured shake-flask log P for this compound was subsequently found to be 1.26, giving a predicted LC50 consistent with the observed value. An upward curvature of the QSAR plot for the most hydrophilic compounds suggests a shift in mechanism for the lowest members of the series.

Amines↗
PubMed1991

Fibrin glue for partial nephrectomy.

Fibrin glue, a mixture of concentrated autologous fibrinogen and bovine-derived thrombin, was used to achieve hemostasis during 7 partial nephrectomies. After transected vessels were suture ligated, topically applied fibrin glue filled all renal defects with an adherent clot that resulted in immediate hemostasis. There was no case of delayed hematoma or abscess formation, and no complications were referrable to the use of fibrin glue. Although fibrin glue is no substitute for early vascular control and careful surgical technique, its ability to stop venous oozing from the cut surface of renal parenchymal tissue dramatically facilitates hemostatic control.

Fibrin Tissue Adhesive↗
PubMed1991

Complications following external beam radiation therapy for prostate cancer: an analysis of patients treated with and without staging pelvic lymphadenectomy.

We reviewed the treatment morbidity associated with definitive high energy external beam radiotherapy in 289 consecutive patients with clinically localized prostate cancer (stages A2 to C) treated from 1984 to 1988 inclusively. All patients were treated with 18 mv. photon beams via a 4-field box technique. Radiation doses ranged from 5,858 to 6,900 cGy., with a mean dose of 6,456 cGy. and a median dose of 6,400 cGy. A total of 65 patients underwent extraperitoneal pelvic staging lymphadenectomy before radiotherapy. Complications noted in 42 patients were mild (generally trivial) in 23 and moderate in 19 (6.6%). There were no severe complications. The actuarial incidence of moderate complications was 9% at 5 years. Only 6 patients experienced symptoms for longer than 6 months. The risk of complications was not increased in patients who had undergone prior lymph node dissection, and only 2 of 65 had mild lymphedema, which resolved in both cases. We conclude that high energy external beam radiation for prostate cancer can be delivered with a low risk of serious complications, even in patients who have undergone extraperitoneal staging pelvic lymphadenectomy, provided the patients are treated to limited fields with high energy photons and at doses limited to 6,800 cGy. or less.

Adenocarcinoma↗
PubMed1991

Prostate specific antigen in patients with clinical stage C prostate cancer: relation to lymph node status and grade.

The preoperatively drawn sera from 84 previously untreated patients who had clinical stage C prostate cancer and underwent staging pelvic lymph node dissections were sent for monoclonal Hybritech analysis to assess the usefulness of prostate specific antigen (PSA) in predicting lymph node status. Of the 84 patients 47 (56%) had positive lymph nodes at surgery. The median PSA value for all patients with nodal metastases was 11.4 ng/.ml., and for those without it was 11.2 ng./ml. Relative to Gleason score, median PSA values were 11.35 for 2-4, 12.2 for 5-7 and 10.9 ng./ml. for 8-10. Within each M.D. Anderson grade median PSA values were 10.15 for grade I, 13.2 for grade II, 12.7 for grade III and 10.5 ng./ml. for grade IV. Simultaneously drawn preoperative frozen serum samples for 28 of these patients were independently analyzed by the Yang radioimmunoassay. Comparing Hybritech and Yang methods revealed strong statistical co-association (correlation coefficient R2 = 97.36, p less than 0.00001) but neither assay was statistically associated with nodal metastasis. Although no PSA level excluded the presence of nodal disease, we suggest that a Hybritech PSA of greater than 30 ng./ml. and a Yang PSA of greater than 50 ng./ml. may serve as a weak adjunctive marker predicting nodal metastasis.

Adenocarcinoma↗
PubMed1991

Transplant coronary artery disease: histopathologic correlations with angiographic morphology.

Accelerated coronary artery disease is a major cause of morbidity and mortality among cardiac transplant recipients. Ten patients who died or underwent retransplantation within 2 months of coronary angiography had direct correlation of angiographic (normal discrete lesions, diffuse concentric narrowing) with histologic appearance of coronary arteries. Of the 26 angiographically normal segments, 73% showed mild to moderate fibrous intimal thickening by light microscopy. The remainder had intermediate lesions or atheromatous plaques. Discrete stenoses usually corresponded to lipid-rich intermediate or atheromatous disease. In contrast, angiographically diffuse, concentrically narrowed lesions usually were areas of severe fibrous intimal thickening. Fresh or organizing thrombus was most often associated with discrete lesions and accounted for all complete occlusions. Histologic and angiographic comparisons of the degree of luminal narrowing showed generally good correlation for high grade stenoses. Lesions graded as having less than 25% diameter narrowing were often underestimated angiographically as compared with histologic determinations. Transplant coronary artery disease has a heterogeneous histologic and angiographic appearance, with angiographic underestimation of disease in some patients.

Adult↗
PubMed1991

Molecular studies of linkage group XIX of Chlamydomonas reinhardtii: evidence against a basal body location.

Linkage group XIX (also known as the UNI linkage group) in the green alga, Chlamydomonas reinhardtii, exhibits a number of unusual properties that have lead to the suggestion that it represents a basal body-associated chromosome. To begin a molecular analysis of this linkage group, we have identified DNA sequences from it and used them to determine the copy number of linkage group XIX within the cell. We find that linkage group XIX is present in the same copy number per cell as nuclear linkage groups in both haploid and diploid strains. We also find that the copy number of linkage group XIX is unchanged in mutants lacking basal bodies. We conclude that there is no convincing evidence that linkage group XIX localizes to the basal bodies of Chlamydomonas reinhardtii cells.

Base Sequence↗