Gastrointestinal lymphoma

The gastrointestinal tract is the commonest site for primary extranodal malignant lymphoma. Despite this, gastrointestinal lymphomas are rare and present diagnostic and conceptual challenges. Principal among these are the differential diagnoses of malignant lymphoma and carcinoma and malignant lymphoma and pseudolymphoma, especially in the stomach; the nature of Mediterranean lymphoma and of the lymphoma complicating celiac disease; and the conceptual basis for differentiation of follicular centre cell lymphomas in the intestine.     

Effect of D-tryptophan on hemolysin production in Vibrio parahaemolyticus

Production of the Kanagawa hemolysin by a strain of Vibrio parahaemolyticus isolated from a gastroenteritis patient was found to correlate with the presence in cell lysates of two unidentified compounds, designated X and Y. The two compounds were present in cell lysates of the organism grown in peptone at the optimal pH for hemolysin synthesis but were not present when cell lysates were grown in peptone at a constant pH of 8.0. They were also absent in cells grown in synthetic medium at pH 6.2 without the addition of D-tryptophan, a condition under which hemolysin is not produced. Both X and Y were present intracellularly only from the time that D-tryptophan was added to synthetic medium, a known method of inducing hemolysin synthesis.     

Mechanisms of trafficking in axons and dendrites: implications for development and neurodegeneration

In the area of routing and sorting of dendritic traffic, the current phenomenological data beg questions about the cellular mechanisms utilized not only to transport material but also to modulate activity in a process, even apoptosis. To aid in formulating testable hypotheses, many plausible models are developed here and linked with some of the preliminary data that supports them. We first assume that in long dendrites the sorting of membranous proteins into transport vesicles also involves the linkage of motor proteins to the vesicles. Second, we assume that the cytoskeleton in dendrites is altered from the cytoskeleton in axons and the cell body. Viral glycoproteins, MAP2 and specific mRNA sorting into dendrites provide the simplest models for analyzing vesicular, cytoskeletal and RNA sorting. In the case of viral glycoproteins, initial sorting appears to occur at the Golgi but additional routing steps involve further complexities that could best be served by an additional sorting step at the junction of the cell body and the process. Transport of the specialized cytoskeletal proteins and specific mRNAs as well as vesicular material could be controlled by a similar gatekeeper at the mouth of a process. Studies of the microtubule-organelle motor complex, regulation of microtubule-based motility by microtubule-associated proteins, and slow axonal transport all provide insights into important aspects of the routing and sorting. These processes are in turn controlled by extracellular signals such as those generated by matrix molecules or their hydrolysis products in the case of amyloid precursor protein (APP). Routing and sorting mechanisms may be central to the development of Alzheimer's disease in view of evidence that APP processing is affected, transport is disturbed, and intracellular vesicles (early endosomes) hypertrophied. Further it is possible that routing mechanisms play a role in cell–cell interactions as, for example, the possibility that pathogenic/cellular stress signals may be passed along circuits transsynaptically.     

The effect on total renal and tubular function and plasma renin of a moderate isotonic saline load in rats anesthetized with amytal and inactin.

The renal effects of i.v. saline loading equal to 1% body weight (b.wt.) were studied in 2 groups of rats: group I was anesthetized with Amytal (15 mg/100 g b.wt. plus supplementary doses), group II with Inactin (12.5-15.0 mg/100 g b.wt.). In group I the saline load caused an increase in urine flow (+92%), solute excretion (+67%), inulin clearance (CIN) (+24%), PAH clearance (+31%) and absolute proximal reabsorption rate (+27%). Proximal fractional reabsorption and filtration fraction (FF) remained unchanged, while plasma oncotic pressure (COP) decreased by 10%. Plasma renin fell and there was an inverse relationship between renin concentration and proximal reabsorption rate. In group II urine flow and solute excretion increased after saline (+85% and 110%, respectively); CIN and absolute proximal reabsorption rate was lower than in group I and failed to increase after saline. Proximal fractional reabsorption was also lower and decreased after saline. COP as well as renin decreased as in group I, but no relationship between renin concentration and proximal reabsorption rate could be demonstrated. The data indicate that Inactin depresses both resting proximal tubular reabsorptive capacity and the tubular response to a physiological volume expansion. The results are compatible with the hypothesis that the renin-angiotensin system is significantly involved in regulation of proximal tubular function, while they are incompatible with the idea that peritubular COP plays any major role in this adjustment.     

Follicular fluid renin concentration and IVF outcome

Total renin protein concentration (TRC) was measured in stored follicular fluid (FF) samples from 42 women. Samples were selected according to their origin from follicles either without recovered ova ('empty', n = 38) or fertilized but with failed implantation ('failed', n = 36) or successful deliveries ('deliveries', n = 71). Ratios of number of embryos transferred to number of infants delivered were 2:1, 3:1 or 4:2 but 1:1 was not available. Non-parametric testing was applied to FF-TRC, volume and outcome. TRC was significantly higher in the delivery than the failed (P = 0.001) or empty (P = 0.002) categories. Assuming that the range of renin in failed follicles can identify the sub-population of unsuccessful follicles in the delivery category, then elevated FF-TRC was clearly associated with successful outcome. For individual women, the odds of infant delivery increased 17-fold as a function of average FF-TRC between 10,000 and 25,000 microIU/ml. For failed and delivery but not empty follicles, higher renin levels occurred in the smaller follicles, consistent with a burst of renin synthesis associated with the presence of an oocyte. The results suggest that FF-TRC relates to ovum viability with ovarian hyperstimulation and may have predictive use in IVF programmes.     

Sarcoma of the pulmonary artery: report of four cases with electron microscopic and immunohistochemical examinations,and review of the literature

Herein we report the clinicopathological features of four cases of pulmonary artery sarcoma that appeared at our institution during a period of 30 years. The patients, 2 males and 2 females, were 50–62 years old. Tumour was found in the pulmonary trunk and right pulmonary artery in all cases, in the pulmonary valve and left pulmonary artery in three of the four cases, and in the right ventricular outflow tract in one case. There was direct extension or metastases to the lungs in two cases, the heart in one case, mediastinum or lymph nodes in two cases and the pleura in one case. Ultrastructural examination in one case revealed cells with features of smooth muscle cells and myofibroblasts. Immunohistochemical examination of three cases gave the following results: vimentin and smooth muscle specific actin was positive in all three cases, desmin in one case and cytokeratin in one case. No positivity was found for Factor VIII. This and other studies indicate that histologically most pulmonary artery sarcomas are leiomyosarcomas or undifferentiated spindle cell sarcomas. Immunohistochemical and ultrastructural examinations favour an origin from myofibroblasts, probably derived from multipotent (undifferentiated) cells in the wall of the vessel. Most lesions show extensive intrathoracic growth although they rarely metastasize outside the thoracic cavity. They have a poor prognosis although some cases are currently being diagnosed during life.     

Incidence of and risk factors for lipoatrophy (abnormal fat loss) in ambulatory HIV-1-infected patients

To identify clinical factors associated with the incidence of HIV-1-associated lipoatrophy, HIV-1-infected patients in the HIV Outpatient Study (HOPS) were prospectively evaluated for clinical signs of lipoatrophy at two visits about 21 months apart. Development of lipoatrophy was analyzed in stratified and multivariate analyses for its relationship to immunologic, virologic, clinical, and drug treatment information for each patient. Of 337 patients with no lipoatrophy at Survey 1, 44 (13.1%) developed moderate or severe lipoatrophy between the two surveys. In multivariate analyses, significant risk factors for incident lipoatrophy were white race (OR = 5.2; 95% CI: 1.9-17.1; =.003), CD4 T-lymphocyte count at Survey 2 less than 100 cells/mm3 (OR = 4.2; 95% CI: 1.3-13.1; =.013), and body mass index (BMI) less than 24 kg/m2 (OR = 2.4; 95% CI: 1.1-5.4; =.024). Analyses that controlled for the severity of HIV illness demonstrated no significant association with use of or time on any antiretroviral agent or class of agents and the development of lipoatrophy. Some host factors and factors associated with previous or current severity of HIV infection, especially CD4 T-lymphocyte cell count, appeared to have the strongest association with incidence of lipoatrophy.     

Purification of a baculovirus-expressed hepatitis E virus structural protein and utility in an enzyme-linked immunosorbent assay.

We report on the purification of the full-length structural protein encoded by open reading frame 2 (ORF-2) of hepatitis E virus. The ORF-2 protein, expressed in Sf9 cells by using a recombinant baculovirus vector system, was successfully purified to homogeneity. Gel electrophoresis of the purified ORF-2 protein showed a single polypeptide of 75 kDa by Coomassie blue staining and by Western blot (immunoblot) analysis. We demonstrated that the partially purified ORF-2 protein could be used successfully in a sensitive and specific enzyme-linked immunosorbent assay for the detection of antibodies to hepatitis E virus.     

A simple and practical technic for detecting cancer cells in urine and urinary bladder washings by flow cytometry

DNA measurement by flow cytometry has been demonstrated to be a potentially useful technic in the diagnosis of bladder cancer by detecting neoplastic cells in bladder washings and urine specimens. The authors' goal was to develop a simple and practical method utilizing the new generation of cytofluorographs designed for use in the clinical laboratory. This method combined direct fixation with cell lysis yielding fixed intact nuclei. Following RNase and pepsin digestion, the nuclei were separated from debris and aggregates on a sucrose barrier, stained with ethidium bromide, and analyzed with an argon laser analytic cytofluorograph. Urines and bladder washings from 14 patients with positive urinary cytology and histologically diagnosed bladder cancers were compared with specimens from patients without urothelial malignancies. DNA histograms clearly delineated aneuploid from diploid populations and often identified S, G2M, and G1 phase nuclei. Aneuploid populations have been detected in all tumor specimens with positive cytologies studied to date.