Search PubMed⌕ Search

Biomedical subjects

G Johnson

Publications and source records attributed to G Johnson.

At least 469 records · Page 26Linked to original sources
PubMed1985

Retiform differentiation in ovarian Sertoli-Leydig cell tumors. A clinicopathologic study of six cases from a Gynecologic Oncology Group study.

This report analyzes six ovarian Sertoli-Leydig cell tumors that showed retiform differentiation. The patients were young (6-29 years; average age, 17). The tumors were all limited to one ovary, and the patients have remained disease-free, with one exception, a patient who died of recurrent neoplasm 3.5 years after operation. On microscopic examination, the retiform areas were predominant in three cases and focal in the other three. The retiform areas consisted of an irregular anastomosing network of spaces lined by cuboidal cells, often with papillary formations and sometimes with tubules compressed to form slit-like spaces. In three cases the retiform areas appeared mature, and in three they were less differentiated. All tumors also had areas of typical Sertoli-Leydig cell tumor of either poor or intermediate differentiation. In the patient with metastatic disease, the metastases had a pure sarcomatoid pattern without any retiform areas.

Adolescent↗
PubMed1985

Aneurysms of the abdominal aorta. Incidence in blacks and whites in North Carolina.

We examined race and sex relative to the unexpected finding of an abdominal aortic aneurysm (AAA) at 1,665 autopsies plus 545 abdominal computed tomographic scans in subjects over the age of 50 years. We compared our demographic data with those of North Carolina and our hospital to determine if the data base was representative. White males had a higher incidence (4.2%) of AAA than any other group of race and sex (1.2% to 1.6%) or combination of groups. Although whites (2.9%) had a higher incidence than blacks (1.5%) and males (3.4%) had a higher incidence than females (1.3%), this can be attributed to the influence of the white male. The demographic data of the group studied were similar to those of our institution's admissions and to the North Carolina population. We conclude that (1) there is an increased incidence of AAA in the white male compared with the white female, black male, and black female in North Carolina; (2) there is no difference in the incidence of AAA in the white female, black male, and black female; (3) race alone may not influence the incidence of AAA as there was no difference between white and black females.

Age Factors↗
PubMed1985

Oral condition of patients with leukemia and severe aplastic anemia. Follow-up 1 year after bone marrow transplantation.

Twenty patients with leukemia and seven patients with severe aplastic anemia who had been treated with bone marrow transplantation were investigated 1 year after transplantation to assess their oral condition. Ten patients had mild clinical chronic graft-versus-host disease (GVHD), and three patients had moderate or severe GVHD. Histopathologic changes in the oral mucosa or the minor salivary glands were observed in nineteen patients. Clinical changes in the oral mucosa were observed in sixteen of those patients. Colonization with Candida albicans was more frequent in patients with advanced histopathologic changes in oral mucosa. The numbers of Streptococcus mutans and lactobacilli and the whole salivary flow rate were not correlated to high or low caries incidence. Whole salivary flow rate were not correlated to GVHD but rather, to conditioning with total body irradiation (p less than 0.05).

Adolescent↗
PubMed1985

Incidence of recurrent or residual stenosis after carotid endarterectomy.

The incidences of recurrent and residual stenosis after carotid endarterectomy have been controversial. Duplex scanning has recently provided an accurate noninvasive method of quantifying areas of arterial narrowing, and this technique was used in 122 postendarterectomy vessels from 71 men and 35 women with a mean age of 65.2 years. The average time interval between operation and scanning was 26.3 months (range 1 month to 11.76 years). Postoperative examination of the internal carotid artery revealed no stenosis in 78 vessels, less than 50 percent area reduction in 17 vessels, 50 to 75 percent stenosis in 11 vessels, more than 75 percent area reduction in 9 vessels, and total occlusion in 7 vessels. Thus, 22 percent of the vessels (27 of 122) had total occlusion or more than 50 percent area reduction after carotid endarterectomy. This is a higher rate of recurrent stenosis than was diagnosed by oculoplethysmography, where 7 of 52 vessels (13 percent) had a positive oculoplethysmogram after operation. These data show that the reported incidence of residual or recurrent stenosis after carotid endarterectomy is heavily dependent on the testing method used. Duplex scanning documents a 22 percent frequency of residual or recurrent stenosis, a figure higher than has been reported with less sensitive tests.

Aged↗
PubMed1985

Dry ice cryoamputation: a twelve-year experience.

Amputation done on an emergency basis of severely ischemic or infected limbs in critically ill patients frequently results in increased morbidity and mortality. To evaluate the effect of delaying an inevitable operative amputation by a simplified method of freezing the involved extremity, the records of 56 patients who underwent preoperative cryoamputation during a 12-year period were reviewed. Data concerning risk factors, associated medical conditions, local or systemic signs of sepsis, level of amputation, morbidity, and mortality were analyzed. Following cryoamputation of 57 limbs, 16 above-knee amputations (AKA) and 41 below-knee amputations (BKA) were performed. The overall mortality rate associated with cryoamputation was 14% (8 of 57); four postoperative deaths occurred in both the AKA and BKA groups. The mortality rate for 1021 primary operative major amputations during the same period was 7% (p less than 0.04). The only factor identified that significantly affected survival following cryoamputation was diabetes mellitus, which was present in 68% of surviving patients and in 12% of those who died (p less than 0.001). This experience suggests that cryoamputation is a valuable, simple technique that allows for deliberate stabilization and preparation of seriously ill, septic patients prior to surgical procedures, which, when performed on an emergency basis have been associated with mortality rates exceeding 40%.

Adult↗
PubMed1985

Protection by Candida albicans of Staphylococcus aureus in the establishment of dual infection in mice.

Candida albicans has been shown to stimulate infection in mice by a number of bacteria when both organisms are inoculated intraperitoneally (E. Carlson, Infect. Immun. 39:193-197, 1983). When subcutaneous and intraperitoneal inoculations were given with Staphylococcus aureus and C. albicans injected at opposite sites, mixed infection was established at the site of fungal inoculation but not at the site of the bacterial injection. Histopathologic evaluation of tissues for the presence of C. albicans and S. aureus after intraperitoneal inoculation of both showed fungal growth in the mesentery and omentum of the abdominal cavity. Cocci were numerous and always associated with the fungi, located within the fungal growth rather than at its periphery. It was concluded that this growth pattern in some way protected the bacteria and was the basis for the generalized fungal stimulation of the bacterial infections observed. In addition to C. albicans, Candida stellatoidea, Candida tropicalis, Candida parapsilosis, Torulopsis glabrata, and heat-inactivated C. albicans also demonstrated some ability to protect bacteria injected simultaneously, although C. parapsilosis and T. glabrata were less effective than the other yeasts in this respect.

Adhesiveness↗
PubMed1985

Alpha 1- and alpha 2-adrenoreceptor relationships in SHRs during hypotension.

Previous studies have suggested that spontaneously hypertensive rats (SHRs) are less able to tolerate the cardiovascular stress of hemorrhagic hypotension than normotensive WKYs. The present studies were designed to determine whether or not this deficiency on the part of the SHRs is related to a genetically derived inappropriate balance between the alpha 1- and alpha 2-adrenoreceptors in the peripheral vasculature. To answer this question, SHRs were divided into untreated controls and experimental rats, which were pretreated with either the relatively specific alpha 1-antagonist prazosin or the alpha 2-antagonist yohimbine. In another series, the adrenal medullae were removed 2-3 days before hemorrhage. The data indicate that alpha 1-receptor blockade might offer some degree of protection to SHRs subjected to hemorrhagic hypotension, whereas inhibition of the alpha 2-adrenoreceptors proved detrimental. We conclude that the innervated alpha 1-adrenoreceptors play a more dominant role in SHR blood pressure regulation than the extrasynaptic alpha 2-adrenoreceptors but that these alpha 1-receptors are unable to maintain the compensatory vasoconstrictor response as effectively as the alpha 2-adrenoreceptors.

Adrenal Medulla↗
PubMed1985

Effects of water immersion on plasma catecholamines in decompensated cirrhosis. Implications for deranged sodium and water homeostasis.

Although an impairment in renal sodium and water excretion is a commonly encountered clinical problem in cirrhotic patients, the mechanisms responsible for this abnormality are uncertain. Norepinephrine (NE) levels are elevated in some patients with decompensated cirrhosis, but a causal relationship between these levels and impaired sodium and water excretion has not been established. Since in normal man, water immersion to the neck (NI) results in a preferential central hypervolemia, and since theoretical considerations suggest that central hypervolemia might suppress NE, we designed the present study to determine if the natriuretic and diuretic responses of cirrhotic patients to NI are mediated by a decrease in NE. 16 cirrhotic patients with ascites were studied on two occasions: during a seated control study and during 4 h of NI: NE, determined by radioenzymatic assay, was measured hourly. 15 of the 16 patients manifested a marked diuresis, and 12 had a natriuresis that equalled or exceeded that documented in normal subjects during NI. NI did not alter mean NE, with 9 subjects manifesting an increase of NE as compared with the prestudy hour. Furthermore, peak urinary sodium excretion and flow rate varied independently of prestudy NE (r = 0.163 and -0.173, respectively), change in NE (r = 0.256 and 0.239), as well as nadir NE levels (r = 0.118 and -0.039). The demonstration of a natriuresis and a diuresis in a majority of the subjects, occurring without concomitant suppression of plasma NE, suggests that NE does not constitute the prepotent determinant in the impaired sodium and water excretion of many patients with advanced liver disease.

Adult↗
PubMed1985

Biologic properties of molecularly cloned and expressed murine interleukin-3.

Interleukin-3 (IL-3) (multipotential colony-stimulating factor [multi-CSF] ) is an important regulator of hemopoiesis. We recently isolated a cDNA clone of this gene and describe in this manuscript the biologic properties of the expressed gene product. An SV40 expression vector carrying cDNA encoding murine interleukin-3 was constructed so that expression of the IL-3 gene was placed under the control of the SV40 early promoter. When the expression vector was transfected to COS-1 monkey cells, IL-3 activity was secreted into the medium, reaching maximal levels 72 hours after transfection. The IL-3 produced by the COS-1 cells was partially purified using diethylaminoethyl Sephacel and phenyl-Sepharose, and its chromatographic properties were the same as IL-3 produced by the WEHI-3 cell line. The biologic activities of the "expressed" IL-3 include the "induction" of 20-alpha-hydroxysteroid dehydrogenase (20-alpha-SDH) in splenic lymphocytes from nu/nu mice, proliferative activity for 32D cl-23 and FDC-P1 cell lines, and colony-stimulating activity for granulocyte-macrophage, eosinophil, megakaryocyte, natural killer-like, erythroid, and multipotential colony-forming cells from murine fetal liver and adult bone marrow.

20-Hydroxysteroid Dehydrogenases↗
PubMed1985

Cardiovascular adrenoreceptor balance during hemorrhagic hypotension and shock.

The primary aim of this study was to examine the hypothesis that the ability of the cardiovascular system to compensate for hemorrhagic hypotension is controlled by a balance between the relative influence of the alpha 1 and extrasynaptic alpha 2 adrenoreceptors. Previous studies have implied that, although both receptors participate in the baroreceptor response to hypotension, only the extrasynaptic alpha 2 receptors are able to maintain the compensatory vasoconstrictor effort for a prolonged period of time. In each experiment two Sprague-Dawley rats were anesthetized and subjected to a modified Wiggers hemorrhagic shock protocol. One rat in each pair was pretreated with either 25 mg/kg of the cyclooxygenase inhibitor sodium meclofenamate or 0.5 mg/kg of the selective alpha 1 antagonist prazosin. The results indicate that neither drug interfered with the normal maximum compensatory effort as defined by the maximum blood loss (ie, reduced total vascular capacitance) when mean arterial pressure (MAP) was reduced to 30 mmHg by hemorrhage. In fact, when normalized for pre-hemorrhage MAP, it was apparent that prazosin, which lowered pre-hemorrhage MAP, may have actually improved the compensatory response. Sodium meclofenamate increased the time to reach the maximum compensatory effort (comp time), while prazosin increased the time to reach 20% uptake from the blood reservoirs (decomp time). Since both drugs enhanced the total time (comp + decomp) and both are known to interfere with alpha 1 function, these studies support the hypothesis stated above.

Animals↗
PubMed1985

Vascular adrenergic interactions during hemorrhagic shock.

The objective of this paper is to review the sequence of vascular events that follows severe hemorrhage. The initial cardiovascular imbalance is a fall in the volume/vascular capacity relationship that leads to reductions in cardiac output and mean arterial pressure (MAP). Peripheral sensors detect the fall in MAP and changes in blood chemistry that cause withdrawal of the normal inhibitory tone from the cardiovascular control centers in the central nervous system. The resulting increased sympathetic activity initiates a series of events that include stimulation of peripheral adrenergic nerves and the adrenal medulla. The magnitude of the compensatory vasoconstriction that follows is the net result of the interaction of the epinephrine (E) from the adrenal medulla and norepinephrine (NE) from the peripheral nerves on the peripheral vascular adrenoreceptors as well as other nonadrenergic mechanisms not discussed here (i.e., angiotensin endogenous opiates). By using pharmacological blocking agents, these adrenoreceptors have been subclassified as: innervated postsynaptic alpha 1; presynaptic alpha 2 (Ps alpha 2); and extrasynaptic alpha 2 (Es alpha 2) adrenoreceptors. The action of E and NE on the alpha 1 and Es alpha 2 receptors initiates the compensatory vasoconstriction, whereas action of these catecholamines on the Ps alpha 2 located on the presynaptic membrane inhibits further release of NE from peripheral nerve terminals, thereby reducing the effect of the innervated alpha 1 receptors. This autoinhibition together with a similar action by prostaglandin E on NE release is thought to be, at least in part, responsible for the vascular decompensation known to occur in the skeletal muscle after hemorrhage. Thus, one of the factors determining survival after hemorrhage may be related to the relative dominance of alpha 1 and Es alpha 2 receptors during the initial compensatory response.

Afferent Pathways↗
PubMed1985

Morphological differences in cutaneous and skeletal muscle vasculature during compensatory and decompensatory hemorrhagic hypotension.

PURPOSE: to determine if morphological differences exist between vasculature shown to decompensate, ie, skeletal muscle (SM) and vasculature that maintains the compensatory effort, ie, cutaneous (C). METHODS: dogs were anesthetized and subjected to a Wiggers hemorrhagic shock protocol. SM and C flows were monitored using electromagnetic flowmeters. Gracilis (SM) and saphenous (C) arterial segments were removed during: prehemorrhage control, compensation, and decompensation. Segments were fixed at in vivo intraluminal pressures. Both light and EM sections were made from each sample. RESULTS: During the compensatory phase, both SM and C showed signs of strong vasoconstriction. Even though the amount of endothelial folding was comparable, the C did and the SM did not sustain the vasoconstriction. Vascular diameters of the SM but not C increased during decompensation. Ultrastructural changes consisted of extreme folding of the internal elastic lamina (IEL) during compensation and subsequent flattening out of the IEL during decompensation in the SM but not the C tissues. Cell deformation, damage, and exfoliation were seen in both SM and C tissues. CONCLUSION: The data are consistent with the theory that SM vasculature, specifically endothelium, synthesizes an inhibitor of NE release, probably prostaglandins.

Animals↗
PubMed1985

Viscous factors in peripheral tissue perfusion.

To ascertain the relative importance of the factors that influence blood viscosity (VIS), we measured hematocrit (HCT), filterability index, fibrinogen level (FIB), and Ektacytometer indices at osmolarities of both 290 (EI 290) and 200 (EI 200) in 21 diabetic patients with peripheral vascular disease (DPVDs) and 11 healthy volunteers (HVs). Stepwise multiple regression analyses generated a formula based on three of the independent variables (FIB, HCT, EI 200) that accurately predicted VIS (r = 0.79, p less than 0.01). Based on the beta coefficients and F statistics, HCT and FIB were the most important elements in the linear regression equation. Compared with HVs the total group of DPVDs had lower HCT (36.5% vs. 42.4%) and higher FIB (661 vs. 276 mg/dl, p less than 0.01) values. When all HVs were compared with a subgroup of DPVDs with similar HCT (n = 10), both FIB and VIS were higher (p less than 0.001) in the DPVD than in the HV group. We conclude that the most important of the multiple factors that influence VIS are HCT and FIB. The finding of increased FIB in DPVDs could have important implications for drug and surgical therapy in this group of patients.

Blood Circulation↗
PubMed1984

Lithium.

Explore the source record for details and available documents.

Aged↗