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Biomedical subjects

J Crowell

Publications and source records attributed to J Crowell.

34 records · Page 2Linked to original sources
PubMed1984

[Clinical and diagnostic considerations on a case of pancreatic plasmacytoma].

An unusual case of obstructive jaundice due to metastatic pancreatic plasmacytoma is described. Initially post-transfusion hepatitis was suspected in the patient who suffered from multiple myeloma (IgA) and had received numerous transfusions for severe anemia. Clinical and laboratory findings indicated obstructive jaundice and the ecographic examination showed a dishomogeneous mass at the level of the pancreas. The investigators suggest that after this type of ecographic finding a percutaneous biopsy should be performed eliminating exploratory laparotomy, a high risk procedure in this type of patient, and eventually radiotherapy should be initiated since this type of tumor is radiosensitive.

Female↗
PubMed1984

[Unusual ultrastructural findings in a case of asymptomatic primary biliary cirrhosis].

The investigators report an ultrastructural study of a case of primary biliary cirrhosis histologically in stage II (Scheuer), a rare disease which has not been investigated extensively at the ultrastructural level. Biliary canaliculi are dilated and microvilli are scarce. Large granular formations are observed in the perisinusoidal cytoplasm. The plasma membrane between adjacent hepatocytes appears convoluted. The ultrastructural alterations of the biliary canaliculi which we observed have been described in the literature in cholestatic patients and ascribed to cholestasis. Our patients, however, has never suffered episodes of jaundice or itching and has no histological signs indicating cholestasis. We suggest that these are precocious alterations which precede the appearance of clinical and histological signs of cholestasis. It is necessary to study other cases in order to evaluate the significance of the large granular formations and the changes observed in the plasma membrane.

Adult↗
PubMed1982

[Ultrastructural changes in hepatocytes of mice treated with morphine].

In a study of the ultrastructure of hepatocytes in mice treated with morphine a statistically significant increase in the volume density and surface density of smooth endoplasmic reticulum (SER) was observed. Morphometric measurements using the method described by Weibel (2,3) were employed to calculate volume density of smooth and rough endoplasmic reticulum mitochondria, and surface density of rough and smooth endoplasmic reticulum membranes and of the mitochondrial envelope and cristae. Statistical analysis using the t test of Student was carried out for all parameters. Both surface density and volume density of SER in mice treated with morphine increased significantly when compared to mice of control group (P less than 0.05 for surface density of smooth endoplasmic reticulum and P less than 0.01 for volume density of smooth endoplasmic reticulum). These ultrastructural changes after administration of morphine and related opiates are not accompanied by an increase of drug metabolizing enzymes and the huge tolerance observed in mice can be a phenomenon of adaptation at the receptor site (4).

Animals↗
PubMed1982

[Ultrastructural changes in hepatocytes of mice treated with heroin].

In a study of the ultrastructure of a hepatocytes in mice treated with heroin a statistically significant increase in the volume density and surface density of smooth endoplasmic reticulum (SER) was observed. Morphometric measurements using the method described by Weibel (2,3) were employed to calculate volume density of smooth and rough endoplasmic reticulum and mitochondria, and surface density of rough and smooth endoplasmic reticulum membranes and of the mitochondrial envelope and cristae. Statistical analysis using the t test of Student was carried out for all parameters. Both surface density and volume density of SER in mice treated with heroin increased significantly when compared to mice of the control group. An increase in volume density of SER is generally believed to be correlated to an increase in drug metabolizing enzymes localized in or on smooth endoplasmic reticulum membranes. We have demonstrated a statistically significant increase in SER in mice treated with heroin which is not accompanied by an increase in drug metabolizing enzymes (7). We feel that further investigation of these anomalous cases is necessary in order to clarify the role of the SER membranes and their function in the metabolism of drugs.

Animals↗
PubMedDate not supplied

The effect of 3-palmitoyl-(+)-catechin on Kupffer cells in guinea pig liver.

We report a morphometric study on the effect of 3-palmitoyl-(+)-catechin on phagocytic activity of latex particles by Kupffer cells in guinea pig liver. We found an increase in the density of latex particles in Kupffer cells of animals treated with 3-palmitoyl-(+)-catechin. The volume and density of Kupffer cells of treated animals increased (p less than 0.01); there was no significant difference in surface density of the plasma membrane. None of the parameters measured was altered in endothelial cells. These results show that 3-palmitoyl-(+)-catechin produces morphological and functional changes in Kupffer cells.

Animals↗
PubMedDate not supplied

Morphological and functional abnormalities in platelets exposed in vitro to ioglicinic acid, a new ionic contrast medium.

The inhibitory effect on platelet function induced by several radiographic contrast media is still poorly understood. In this study platelet abnormalities caused by in vitro addition of ioglicinic acid, a new ionic contrast medium, were evaluated. The appearance of several granules similar to dense bodies associated with shape change and internal reorganization were detected by electron microscopy techniques. A functional study revealed a marked decrease in the aggregating response of platelets to adenosine diphosphate and calcium ionophore A23187, while aggregation in response to collagen was completely normal. It is suggested that ioglicinic acid induces platelet abnormalities related to the effect on calcium movements and that studies with this contrast medium may help the understanding of some basic events of platelet activation.

Adult↗
PubMedDate not supplied

Combined oral isoprinosine-intraventricular alpha-interferon therapy for subacute sclerosing panencephalitis.

Eighteen patients, 16 boys and 2 girls, aged 5-14 years, with subacute sclerosing panencephalitis (SSPE) were treated with oral isoprinosine (100 mg/kg/day) and intraventricular alpha-interferon 2b (Intron A, Schering Corp.), starting at 500,000 U twice a week and later increasing to 3 million U biweekly. Minimal follow-up of living patients is 12 months; maximal 40 months. On the basis of the Neurological Disability Index (NDI) scores and staging, 8 have treatment-induced remissions (3 improved, 5 arrested), 4 are worse and 6 died. This 44% (8/18) rate of remission/improvement compares well with the 9% (1/11) remission in historical controls in the same institution (p = < 0.05) and 5% spontaneous remission in the literature. Combined oral isoprinosine-intraventricular alpha-interferon appears to be an effective treatment for SSPE.

Administration, Oral↗
PubMedDate not supplied

Attachment security in infancy and early adulthood: a twenty-year longitudinal study.

Sixty White middle-class infants were seen in the Ainsworth Strange Situation at 12 months of age; 50 of these participants (21 males, 29 females) were recontacted 20 years later and interviewed by using the Berkeley Adult Attachment Interview (AAI). The interviewers were blind to the participants' Strange Situation classifications. Overall, 72% of the infants received the same secure versus insecure attachment classification in early adulthood, K = .44, p < .001. As predicted by attachment theory, negative life events-defined as (1) loss of a parent, (2) parental divorce, (3) life-threatening illness of parent or child (e.g., diabetes, cancer, heart attack), (4) parental psychiatric disorder, and (5) physical or sexual abuse by a family member-were an important factor in change. Forty-four percent (8 of 18) of the infants whose mothers reported negative life events changed attachment classifications from infancy to early adulthood. Only 22% (7 of 32) of the infants whose mothers reported no such events changed classification, p < .05. These results support Bowlby's hypothesis that individual differences in attachment security can be stable across significant portions of the lifespan and yet remain open to revision in light of experience. The task now is to use a variety of research designs, measurement strategies, and study intervals to clarify the mechanisms underlying stability and change.

Adult↗
PubMedDate not supplied

The relationship of Mlsx to Mlsc.

Among T cell clones with specificity for cow insulin and autologous class II MHC products, a significant number displayed interesting patterns of alloreactivity to non-MHC antigens. Four clones are described in this report. One is a typical Mlsa-reactive clone, while the other three proliferate to a variety of allogeneic spleen cells with reportedly different Mls phenotypes. These include PL/J stimulator cells, designated Mlsx, all strains reported to be Mlsc, and several strains previously typed as Mlsa. Little is known about Mlsx except that it does not appear to be cross-reactive with Mlsa. In this report, therefore, we attempt to investigate the reasons why these clones seem to be stimulated by a variety of different Mls phenotypes. Our conclusions are, first, that some of the strains previously typed as Mlsa may actually express a second Mls product, either c or x, in a manner analogous to the CBA/J strain (which expresses both Mlsa and Mlsc), and second, that Mlsc and Mlsx are cross-reactive. In preliminary experiments, we investigate the genetic relationship between Mlsc and Mlsx by analysis of backcrosses, and the extent of cross-reactive recognition of Mlsc and Mlsx by raising T cell clones which recognize one but not the other. Our preliminary conclusion is that Mlsc and Mlsx are cross-reactive, but represent distinct gene products.

Alleles↗
PubMedDate not supplied

The effect of temperature on the ultrastructure of Histoplasma capsulatum during the mycelium-yeast transition.

The ultrastructural morphology of the early phases of mycelium-yeast transition in Histoplasma capsulatum after a temperature shift from 25 degrees C to only 34 degrees C is described. Under this condition of lower temperature oxidative phosphorylation is not completely uncoupled and maximum production of heat shock proteins (hsp) occurs. 24 h after temperature shift more than 90% of the cells still appear vital. Alterations in the organization of the mitochondrial cristae are the only ultrastructural changes observed in these cells. In contrast, 70% of the cells degenerate 24 h after a temperature shift from 25 degrees C to 37 degrees C and in the remaining cells mitochondria are rarely observed. These observations are discussed in relation to the production of hsp, the uncoupling of oxidative phosphorylation and the virulence of different strains of H. capsulatum.

Heat-Shock Proteins↗