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Purpose: Calcium channel blockade has been shown to inhibit experimental atherosclerosis in cholesterol-fed animals, and early clinical trials suggest its benefit in human subjects as well., Methods: To determine the effect of the calcium channel blocker nifedipine on lipid and monocyte infiltration of the subendothelial space, an endothelial cell (EC)-smooth muscle cell (SMC) bilayer model of the arterial wall was incubated for 18 hours with nifedipine (0.1 micrograms/ml). Iodine 125-labeled low-density lipoprotein (125I-LDL) (10 micrograms protein/ml) was then added to the upper-well medium., Results: After a 3-hour incubation period, nifedipine-treated bilayers showed an increased permeability to LDL (p < 10(-7). Nifedipine had no effect on the membrane binding or cellular uptake of LDL by the EC but did increase SMC binding and uptake (p < 0.0005). U937 monocytes were found to incorporate 125I-LDL in a concentration-dependent fashion, without saturation to 25 micrograms/ml, the highest concentration studied. Nifedipine increased monocyte uptake of LDL (10 micrograms/ml; p < 0.003 but reduced monocyte movement through the EC barrier (p < 10(-7). A study of the selective preincubation of each cell type (EC, SMC, and monocyte) with nifedipine indicated that this reduction was likely the result of a direct effect on the monocyte., Conclusions: Given the potential cytotoxic effects of the monocyte within the subendothelial space, nifedipine-induced inhibition of monocyte infiltration and enhancement of lipoprotein uptake by the SMC may be protective.

Stool specimens were collected from healthy neonates at Ga-Rankuwa Hospital in the winters of 1984 and 1986 and tested for the presence of rotavirus infection. Asymptomatic excretion was found to occur in 25% of the newborn babies analysed. Gel electrophoresis of the rotavirus RNA genome revealed that a genomically stable strain of rotavirus was endemic in the ward at the time intervals examined. Hybridisation analysis of the VP4 and VP7 rotavirus genes, which encode the outer capsid neutralization proteins of the virus, was conducted. These results showed the presence of a serotype 4 rotavirus strain with an M37-like VP4 gene allele, which remained conserved in the nursery over the time period examined. Partial nucleotide sequences were obtained for a variable region of the VP7 gene and for the hyperdivergent region of the VP4 gene from 8 of these viruses and showed that remarkable conservation of these regions in the genes of the viruses occurred over time.

Thrombin, a mediator of thrombosis, has been shown to directly alter the function of vascular cells. We studied the effect of thrombin on low-density lipoprotein permeability and uptake by an arterial endothelial cell-smooth muscle cell bilayer to determine its potential role in atherogenesis. Confluent cell bilayers were incubated in media containing thrombin (10 or 50 units/ml) for a period of 24 hours to 9 days. Iodine 125 (125I)-LDL (10 micrograms protein/ml) was then added to the media, and after a 3-hour incubation, 125I-LDL transit through the endothelial cell layer as well as membrane binding and uptake by each cell type were measured. The lower concentration of thrombin caused a delayed increase in both the permeability (p less than 0.0001) and uptake (p less than 0.05) of LDL, but had no effect on membrane binding of the lipoprotein. The higher thrombin concentration led to an immediate increase in endothelial cell permeability to LDL (p less than 10(-7)) and a significant reduction in both cellular uptake (p less than 10(-7)) and membrane binding (p less than 0.0005). In contrast, smooth muscle cell binding and uptake were unaffected at the lower concentration of thrombin. At the higher concentration, smooth muscle cell uptake of LDL was increased (p less than 10(-7)) disproportionately to a more limited increase in membrane binding (p less than 0.05). Endothelial DNA content, reflecting cell number, was increased at 10 units/ml thrombin (p less than 0.001) but markedly reduced at 50 units/ml thrombin (p less than 0.0005), whereas smooth muscle cell DNA content remained unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

Unilateral lower extremity edema and an increased risk of thromboembolism have been associated with hemiplegia following stroke. This study was undertaken to determine the effect of knee-high, graded elastic stockings on venous hemodynamics in hemiplegic patients. Thirty-six patients with recent cerebral infarcts were studied. The presence of underlying venous or arterial occlusive disease was excluded in all patients. Duplex scanning techniques were used to measure femoral and popliteal venous circumference, cross-sectional area, and peak flow velocity in the normal and paralyzed extremities both with and without stockings. All patients were examined and assessed for the degree of motor weakness and Brunnstrom stage of recovery. Associated medical illnesses were also reviewed. These patients were found to have a decreased flow in the femoral (p = 0.0002) and popliteal (p = 0.006) veins and an increase in the femoral vein size. The application of compression stockings resulted in a significant increase in venous size and flow velocity in both areas. The femoral and popliteal velocity correlated inversely with the degree of motor impairment and Brunnstrom stage, suggesting that factors other than the muscle pump may be responsible for the augmentation of femoral flow velocity in the paralyzed leg. There was no correlation demonstrated with other variables such as age, gender, cardiovascular disease, or diabetes. These results would indicate a potential benefit of graded knee-high elastic compression stockings in reducing venous flow stasis in hemi-paretic patients., (Copyright © 1992 National Stroke Association. Published by Elsevier Inc. All rights reserved.)

Rotaviruses were detected in 32.8% (71/216) of stool specimens collected from young children with gastro-enteritis attending the Rehydration Unit at Umtata General Hospital between April 1988 and March 1989. A seasonal distribution was observed with an increase in numbers shedding the virus during the colder months of the year. Based on variations in the migration pattern of the RNA genome segments when passed through polyacrylamide gels, 14 different electrophoretypes were identified: 69% were long patterns and 27% were short patterns. A single dominant long electrophoretype persisted throughout the 12-month study period, whereas 13 other minor types co-circulated at varying intervals. Mixed infections were observed in three cases, including one infant who was infected with both a long (Wa-like) virus and a short (DS-1-like) virus.

There is evidence to suggest that the deposition of lipid within the arterial wall, which is characteristic of atherosclerosis, involves a break in the integrity of the endothelial barrier. Oxidative modification of low density lipoproteins by reactive oxygen species may enhance this process. In this study, an aortic endothelial (EC) smooth muscle cell (SMC) bilayer was briefly exposed to a free-radical generating system to determine the effect of superoxides on lipid permeability and uptake. 125I-LDL (10 micrograms/ml) was added to the EC medium at various time intervals (3, 24, and 48 hr and 9 days). The amount of lipid reaching the subendothelial space was measured. Measurements of EC and SMC binding and uptake of LDL were also obtained and compared with those of untreated cells. The results demonstrate a significant increase in the permeability of the treated EC layer to LDL (P less than 10(-6)), which was sustained over time. Superoxide exposure led to a limited initial increase in EC binding and uptake of LDL, which later returned to control values. In contrast, SMC uptake of LDL was significantly (P less than 10(-3)) and persistently increased over control values and disproportionately increased over cellular binding. Such results suggest that superoxides can increase LDL permeability of the EC barrier. Because this was not associated with a comparable increase in EC binding and uptake, it is unlikely to be due to changes in receptor-mediated, transcellular transport.(ABSTRACT TRUNCATED AT 250 WORDS)

The use of venoplasty to widen the antecubital venous outflow during the placement of arterio-venous grafts in the forearm for angioaccess is described. This has allowed an increased use of grafts for the forearm for angioaccess in instances in which antecubital veins were otherwise believed to be inadequate in size. Expansion of the venous outflow tract may also increase the long term patency of these grafts.

Thirty-two patients undergoing limb salvage procedures for complex vascular and orthopedic injuries of the lower extremity were studied in order to identify prognostic indicators for delayed amputation in this select group. A high incidence of nerve (38%), soft tissue (66%), and remote injury (47%) was noted. A comprehensive and integrated approach to vascular, orthopedic, and plastic reconstruction was utilized. Of the 32 patients studied, 1 (3.1%) died as a result of remote injury and sepsis. Amputation was required in 9 patients (28%), while 13 (56%) of the patients with limb salvage showed persistent functional or neurologic deficits. Infection was the most significant factor associated with amputation (p less than 0.0005) and was not avoided by the perioperative use of antibiotics. Delayed amputation resulted in a significant extension of total hospitalization (p less than 0.005). The authors favor an aggressive approach to limb salvage with IIIC injury but recommend early amputation in the presence of significant nerve disruption. An attentive use of tissue debridement, intravenous antibiotics, and early wound coverage is needed to limit infection.

To study the interaction of endothelial and smooth muscle cells, and the means by which such interaction may affect lipid permeability of the arterial wall, cell bilayers were established by use of a transwell culture system. After confluent growth of both cell types had been achieved, iodine 125 bound to low-density lipoprotein (10 ng protein/ml) was added to the media of the upper well. After a 3-hour incubation period, the iodine 125-bound low-density lipoprotein content of the upper and lower media demonstrated an impedance to lipoprotein movement across the endothelial cell monolayer as compared to the bare porous polycarbonate filter of the transwell (p less than 10(-6)). The presence of smooth muscle cells in the bottom well significantly enhanced the permeability of the endothelial cell layer (p less than 10(-60). This effect remained unchanged over a 9-day time course. Membrane binding and cellular uptake of low-density lipoprotein by endothelial cells was not altered by smooth muscle cells, indicating that this change in permeability could not be easily attributed to changes in receptor-mediated transport or transcytosis. Membrane binding (p less than 0.02) and cellular uptake (p less than 10(-6)) of low-density lipoprotein by smooth muscle cells in the bilayer, when adjusted for counts available in the smooth muscle cell media, were both reduced in the early incubation period as compared to isolated smooth muscle cells. The disproportionate reduction in uptake as compared to binding would suggest that this was not entirely a receptor-dependent process.(ABSTRACT TRUNCATED AT 250 WORDS)

Interactions between vascular endothelial (EC) and smooth muscle cells (SMC) contribute both to the normal function of the vascular wall and to the pathogenesis of lesions such as atherosclerosis and fibrointimal hyperplasia. However, study of these interactions has been hampered by the difficulty in growing these two cell types in simultaneous culture. Methods using conditioned media, shared media, and bilayer culture have been described, but none is well suited to the study of vascular cell interactions. We report a method for EC-SMC co-culture that preserves bilayer morphology, allows independent study of the cells and their matrices after intervention, remains stable over long periods in culture, and permits study of changes in cell-cell interaction with growth of the cells to confluence. This simple bilayer co-culture system simulates the in vivo situation and may enhance our understanding of EC-SMC interactions.

The antiatherogenic effect of high density lipoprotein (HDL) has been attributed to either an inhibition of cholesterol uptake or to reversed cholesterol transport from peripheral cells. In order to determine whether HDL competitively blocks receptor-mediated low density lipoprotein (LDL) binding and uptake, bovine aortic endothelial cells (BAECs) were cultured in Dulbecco's modified Eagles Medium (DMEM) containing 10% LDL-free fetal bovine serum, and incubated with 125I-LDL in concentrations of either 10 or 25 micrograms protein/mL. Varying amounts of HDL (0-200 micrograms/mL) were added to the media. Following a twenty-four hour incubation period at 37 degrees C, 125I-LDL binding and uptake were measured. At the lower concentration of 125I-LDL, which represents high-affinity receptor binding, there was no significant difference in either binding or uptake within the range of HDL concentrations studied. At the higher concentration of LDL, however, there was a marked inhibition of 125I-LDL binding (p less than .006) and uptake (p less than, 001; ANOVA), which did not saturate at the highest HDL concentrations used. These data suggest that HDL does not influence high-affinity, receptor-mediated binding and uptake of LDL but that its effect is seen at a concentration of LDL representing nonspecific binding. The lack of saturation at increasing concentrations of HDL also indicates that HDL-receptor interaction is not essential for the effect.

High-density lipoprotein (HDL) may inhibit the binding and cellular uptake of low-density lipoprotein (LDL) as one means of regulating the delivery of exogenous cholesterol to nonhepatic tissues. This may play an important role in atherogenesis, by altering lipid metabolism in cells of the arterial wall. To verify and better characterize this effect, endothelial cells were harvested from bovine aorta and maintained in tissue culture. Following initial preincubation in lipid-deficient culture media, these cells were incubated for 2 hr at 4 degrees C in media containing 125I-LDL (10 micrograms protein/ml) and varying concentrations of either HDL (0-400 micrograms protein/ml) or comparable amounts of Apoprotein A (Apo A), the major protein component of HDL. Intracellular and trypsin-released counts were assayed separately, as a measurement of cellular uptake and membrane bound LDL, respectively. Results of this study indicated an inhibition of LDL binding and uptake by HDL (P less than 0.005, ANOVA). A similar inhibition was found with Apo A alone (P less than 0.005). When identical studies were performed using 125I-Apoprotein B, the protein component of LDL, and Apo A, the latter was found to inhibit the binding of Apo B to the same extent (P less than 0.0006). These results indicate that HDL does inhibit LDL binding and uptake by bovine aortic endothelial cells and that, because this effect is seen equally with only the protein component of these lipoprotein particles, it is most likely due to competitive binding at the receptor level rather than to stearic hindrance or an alteration of the cell membrane.

Recent evidence suggests that thrombin interacts with various cell types, stimulating cellular proliferation and protein and prostanoid production. To further delineate its role in vascular healing, we have studied the effects of thrombin on proliferation and matrix production by the cells of the vessel wall. The addition of thrombin (1 unit/ml) to cultures of bovine aortic smooth muscle cells resulted in an increase in cell proliferation (p less than 0.01) and number (p less than 0.03), whereas in cultures of bovine aortic endothelial cells thrombin produced a decrease in cell proliferation (p less than 0.01) and number (p less than 0.02). Thrombin also altered matrix composition in cultures of these cells. In both bovine aortic endothelial cells and bovine aortic smooth muscle cell cultures grown in the presence of thrombin, total protein content was significantly increased when compared to controls (p less than 0.03). In bovine aortic endothelial cell cultures the addition of thrombin resulted in a decrease in collagen content (p less than 0.01) and an increase in sulfated glycosaminoglycan content (p less than 0.02). In contrast, in bovine aortic smooth muscle cell cultures thrombin resulted in an increase in collagen content (p less than 0.03), whereas glycosaminoglycan content was unaffected. These findings suggest that thrombin may significantly influence vascular healing and function by altering cell number and matrix composition.

Aortic dissections limited to the abdominal aorta occur infrequently. We have identified four cases of abdominal aortic dissection and have reviewed these in combination with 43 previously reported cases to identify factors that influence the prognosis and management of this disease. Abdominal aortic dissections are similar to thoracic dissections in their presentation, with acute shearing pain and systolic hypertension occurring commonly. Although the diagnosis may be made by ultrasonography or CT scanning, angiography is the definitive diagnostic study. Factors found to be associated with high mortality include presentation with acute pain (p less than 0.0003), involvement of visceral vessels (p less than 0.02), and rupture (p less than 0.000002). Chronicity appears to be protective (p less than 0.04), although chronic dissections may present acutely. Although prosthetic replacement of the involved aorta is the treatment of choice in most cases, nonoperative management with regular follow-up can be considered in asymptomatic chronic dissections.

The case is presented of a 38-year-old woman who suffered multiple cerebellar infarctions as a result of emboli from a vertebral artery dissection. Surgical therapy led to a satisfactory recovery. This case emphasizes the importance of an aggressive approach to such lesions.

PLC/PRF/5, a tissue culture cell line isolated from a human hepatocellular carcinoma and producing hepatitis B surface antigen, was studied for the presence of hepatitis B virus (HBV)-specific DNA and RNA. PLC/PRF/5 cell DNA accelerated the rate of reassociation of HBV [32P]DNA, and quantitative experiments indicated that the cells contained approximately four copies of viral DNA per haploid, mammalian cell DNA equivalent. PLC/PRF/5 DNA accelerated the rate of reassociation of all individual restriction endonucleases HincII and HaeIII fragments of HBV [32P]DNA, indicating that DNA from all regions of the viral genome is present in the cells. This suggests that these cells contain at least most, and possibly all, of the viral genome. Digestion of PLC/PRF/5 cell DNA with restriction endonuclease HindIII (an enzyme found not to cleave the DNA of any HBV isolate so far examined) yielded only three fragments, all larger than virion DNA, which contained HBV DNA base sequences, suggesting that HBV DNA is integrated in high-molecular-weight DNA at three different sites in these cells and that there is no viral DNA in an episomal form. PLC/PRF/5 cell [32P]RNA was found to hybridize with all restriction fragments of HBV DNA adequately tested, indicating that at least most, and possibly all, of the viral DNA in these cells is transcribed.

The effects of free and liposome-encapsulated bleomycin and adriamycin on a human hepatocellular carcinoma cell line were studied in vitro. Free and encapsulated bleomycin inhibited cell growth over 24 hours by the same amount, but DNA synthesis was inhibited more by the encapsulated form. Twenty-five per cent of the cell population showed drug resistance to the free drug, whereas this decreased to 17% with encapsulated bleomycin. These results suggest that the cell membrane plays a role in bleomycin resistance, and that cell death is not solely due to inhibition of DNA synthesis. Encapsulated adriamycin inhibited cell growth and DNA synthesis by the same amount or less than the free drug. Possible explanations are that adriamycin exerts its main cytotoxic action by interacting with the cell surface, or that at the low concentrations used, free drug is taken up more efficiently than the encapsulated drug. Liposomes as drug carriers constitute a useful system for studying the basic mechanisms involved in drug action and in particular the role played by cell membranes.

Faecal specimens from 122 infants in the Neonatal Unit at Ga-Rankuwa Hospital were examined by electron microscopy for the presence of virus. In total 40% of the neonates were excreting virus. Rotavirus was the commonest, found in 33.5% of the infants, with small round viruses (SRVs) found in 12.3% and adenovirus seen in 1 baby. RNA analysis of the rotavirus genome revealed a similar electrophoretype in all specimens. Most of the babies infected with rotavirus were less than 7 days old, and very little excretion occurred after 21 days of age. Only 8% of the babies excreting virus had any clinical signs of infection. Rotavirus infection appears to be endemic and SRV infection common in the Neonatal Unit at Ga-Rankuwa Hospital.

Between March 1983 and December 1986, a total of 1571 stool specimens were collected from black South African infants and young children with acute gastroenteritis, and tested for the presence of rotavirus. Monoclonal antibodies against the major inner capsid protein were used in an enzyme linked immunosorbent assay to determine the subgroup specificity of the rotavirus isolates. Subgroup II rotaviruses occurred more frequently than subgroup I isolates (74.4% vs 12.3%), while 13.3% could not be typed and may indicate the presence of a third subgroup. Two of the subgroup I isolates had a long RNA profile (ie, faster moving gene segment 11) typical of the subgroup II human rotaviruses, and a single subgroup II strain had a short RNA profile possibly indicating an in vivo rotavirus reassortant.

Hepatitis A virus (HAV) was isolated directly from human feces and propagated serially in an HBsAg producing human hepatoma cell line. No cytopathic effect was observed in the tissue culture and no detectable amounts of HAV were present in the tissue culture supernatant fluid. However, increasing amounts of hepatitis A antigen (HAAg) were detected by radioimmunoassay in the cell extracts obtained by freezing and thawing of cells. Specificity of the HAAg determination was shown by neutralization with convalescent sera of marmosets experimentally infected with the MS-1 strain of hepatitis A and by the absence of this neutralization with preinoculation sera. HAAg was first detected after four weeks in the cell extract of infected cultures after inoculation of 10(2)--10(4) tissue culture infectious doses of HAV from second passage.

The major part of APGA Press production editor's jobs is copy editing manuscripts before they are set in type. In this article, written at the invitation of the P&G editor, two APGA Press Staff members use specific examples to illustrate the grammatical and stylistic errors that cause problems for them and, if not corrected, for readers. The authors hope that contributors and potential contributors to professional journals will find this article helpful in expressing their ideas clearly when preparing material for publication.

Some authorities state that urine may be refrigerated overnight and still be satisfactory for quantitative bacteriologic evaluation. The papers cited appear to us to be inadequate. Four hundred and fourteen urine cultures were evaluated comparing colony count before and after overnight refrigeration. Overnight refrigeration appears to be a satisfactory means of urine preservation for culture.

In order to identify patients who, having had an initial pulmonary embolism, are likely to develop recurrent emboli despite adequate anticoagulation therapy, ten patients (group 1) with documented recurrent pulmonary embolism during anticoagulation therapy were compared with 31 patients (group 2) who showed no evidence of recurrent emboli during the treatment period. Risk factors for thromboembolic disease were similar between the two groups. Noninvasive venous studies of the lower extremities, including Doppler venous ultrasound and phleborheography (PRG), were performed upon all patients after the initial embolic event. Of the ten patients in group 1, seven (70 per cent) had clinical signs of deep vein thrombosis (DVT). Doppler studies were positive for eight of the nine patients studied, and PRG studies were positive for eight of eight patients tested. In contrast, of the 31 patients who responded well to medical therapy, one patient (3 per cent) had clinical signs of DVT, three patients (10 per cent) had positive Doppler studies and one patient (3 per cent) had a positive PRG. Combined Doppler and PRG studies were positive in 100 per cent of the patients in group 1 but in only 6 per cent of the patients in group 2 (p less than 0.001). The results of this study suggest that patients having an initial pulmonary embolism and DVT of sufficient extent detected by noninvasive studies may be at an increased risk for recurrent PE despite anticoagulation therapy. Insertion of a vena cava filter should be considered in these patients prior to the second embolic event.

The inhibition of atherosclerosis by estrogen has been shown clinically and experimentally, but the mechanism by which this occurs is unknown. Previous studies have shown that estrogen enhances the uptake of low-density lipoprotein (LDL) by bovine aortic endothelial cells (BAEC) while not altering membrane binding at saturating levels of LDL. In this study the effect of estrogen on LDL binding kinetics has been investigated. Computer-assisted Scatchard analysis of binding data suggests a single-site binding model. Estrogen-treated BAEC showed a lower binding affinity (Ka = 2.47 +/- 0.74 E7 M-1) than control cells (1.95 +/- 0.21 E7 M-1) (p = 0.0012). Estrogen-treated cells, however, had a greater binding capacity (Bmax = 1.26 +/- 0.07 E-10M) than control cells (Bmax = 8.49 +/- 0.44 E-11M) (p = 0.0004). The latter was due primarily to a difference in LDL binding at higher concentrations of LDL (greater than 40 micrograms/ml). These findings are consistent with an estrogen-stimulated increase in low-affinity binding of LDL to BAEC, which may not be directly receptor mediated and which appears to enhance the uptake of LDL at higher lipoprotein concentrations. Such alterations in LDL uptake by endothelial cells could influence the formation of atherosclerotic plaque.

From March 1983 to February 1985, rectal swabs were collected from the black infants admitted to the gastroenteritis unit at Ga-Rankuwa Hospital, Pretoria, Republic of South Africa, to investigate the prevalence of rotavirus-associated gastroenteritis. Overall, 23.1% of the patients tested were found to be positive for rotaviral illness; a definite seasonal pattern emerged, showing a marked increase in the number positive during the autumn. Other factors of importance in terms of rotaviral illness included the age distribution of the patients, the presence of vomiting, and duration of illness.

Hepatitis B virus surface antigen (HBsAg) could be studied until recently only by isolating it from the blood of carriers, thus making incorporation of radioactive precursors into this protein(s) impossible. The isolation of a cell line producing HBsAg [Alexander et al, 1978] has eliminated this obstacle. The cell line was therefore used for labeling HBsAg either with 35S-methionine or with 35S-cystine. HBsAg was purified by pelleting the component and by isopycnic centrifugation in CsCl gradients. HBsAg-positive fractions (as determined by solid-phase radioimmunoassay) were isolated from the gradients and analyzed in sodium dodecyl sulfate-containing polyacrylamide gels. It was found that although HBsAg contains substantial amounts of 35S-cystine, very little 35S-methionine was incorporated into this protein. In contrast, both labels were found in other structures having a buoyant density of about 1.3 gm/cm3 in CsCl. It was concluded that HBsAg is very low in methionine, and therefore this amino acid should not be used for labeling HBsAg in cells or in a cell-free system. Analysis of 35S-cystine-labeled HBsAg-positive material (buoyant density about 1.2 gm/cm3 in CsCl) revealed five proteins with molecular weights in the range of 48,000-82,000.

In 1831 James Syme described the unusual occurrence of an aortocaval fistula in a 22-year-old man with luetic aortitis. This initial report was followed by illustration of this phenomenon in Rokitanski's Book of Pathologic Anatomy in 1841 and by Ryle's delineation of an aortocaval fistula on a pathologic specimen placed in Guy's Hospital Museum in 1892. The first series of aortocaval fistulas, cited by Rudolf Matas in 1909, consisted of a collection of 20 cases gathered by Boinet 10 years earlier. Several later reports, including those by Reid in 1925 and by Lehman in 1938, failed to add any additional cases. It was not until 1955 that Boffi presented an additional six patients who had this disorder, none of whom survived. Since that time, more than 100 cases of spontaneous aortocaval fistulas have been documented. This increasing experience has resulted in improved understanding and surgical treatment of these large-vessel arteriovenous communications. Nevertheless, lack of awareness and failure of recognition of this problem continue to impede its successful management. In this review we present two additional illustrative cases, summarize the clinical and pathophysiologic features of aortocaval fistulas, and outline present approaches to treatment.

A dose of 10 microgram/ml bleomycin inhibited the growth of oesophageal carcinoma cells and non-squamous cells in vitro. Drug concentration, density of cells and the time of exposure to the drug were important variables. The oesophagus cancer cells increased in volume by 2,5 +/- 0,2% per hour until the onset of lysis at 96 hours. The effects of the drug were irreversible even when the exposure time was only 24 hours. A certain proportion of the cell population was resistant to bleomycin and these cells remained resistant when the drug was removed for 48 hours and then replaced. No drug inactivation or uptake could be detected with the use of microbiological assay after 4 days of incubation with 3 cell types. There is poor correlation between in vitro and in vivo results.

Membrane fluidity, transmembrane signaling responses, and proliferative characteristics of endothelial cells were studied to characterize biochemical and molecular changes after treatment with argon laser energy. Bovine aortic endothelial cells grown in monolayers were irradiated at 50, 100, and 200 J with an argon laser (wavelength, 488 and 514 nm). Proliferation, assayed by [3H]thymidine incorporation, was measured daily for 6 days. An initial lag phase was observed for irradiated cells when compared to nonirradiated controls (P less than 0.03), with eventual recovery by the third day. Membrane fluidity, determined by fluorescence anisotropy, was measured 1 hr after irradiation. A decrease in static rotational motion of 1,6-diphenyl-1,3,5-hexatriene (DPH) was noted in irradiated versus nonirradiated cells indicating a decrease in membrane fluidity (P less than 0.02). Dynamic studies of intracellular calcium and pH flux utilizing fluorescent probes demonstrated a preserved response to mitogenic stimulation. An increase in intracellular Ca2+ with a concomitant alkalinization of the intracellular milieu was observed in irradiated and non-irradiated cells in response to stimulation with endothelial cell growth factor (ECGF). These responses resemble those characterized for other mitogens. Argon laser energy applied to aortic endothelial cells decreases membrane fluidity early after irradiation. These alterations probably cause the initial lag observed in their proliferative response; however, the capacity to respond to exogenous mitogenic stimulation is maintained.

The human hepatoma cell line, PLC/PRF/5, was shown to produce hepatitis B surface antigen (HBsAg). Immunologically reactive material was present in the supernatant tissue culture medium in significant amounts, and was associated with spherical particles approximately 20 nm in diameter. The rate of antigen production by the cells was estimated at 500 ng/day/10(6) cells by reference to a purified HBsAg standard. All immunological activity was neutralized by specific antibody and the subtype was ad. The studies reported here broaden the scope of investigations on both the in vitro production of HBsAg and the association between this antigen and primary liver cancer.

The PLC/PRF/5 cell line derived from a human hepatoma produces hepatitis B surface antigen (HBsAg) in 22-nm particles of the same buoyant density as those found in the serum of infected patients. The HBsAg particles from this cell line were labeled with [35S]methionine and purified, and the polypeptides were compared by sodium dodecyl sulfate-polyacrylamide gel electrophoresis with those of serum-derived particles. The two major polypeptides of serum-derived HBsAg particles (p20 and p23) were found in the same relative amounts in the particles from the cell line. The three smallest of the five minor components observed in HBsAg particles from serum were present in particles from the cell line. These polypeptides (p31, p36, and p43), as well as p20 and p23, were precipitated with anti-HBs-containing serum. The two largest polypeptides of serum particles (p49 and p66) were not detected in particles from these cells. When the PLC/PRF/5 HBsAg particles were radiolabeled with tritiated sugars, p23, and not p20, was found to contain radioactivity, indicating that the pattern of polypeptide glycosylation is similar to that of serum HBsAg. None of the other possible gene products of hepatitis B virus was detected in the PLC/PRF/5-derived HBsAg particles, in the cells, or in the cell supernatants.

During a prospective 3-year study, clinical and epidemiological features of rotavirus gastroenteritis in black infants were investigated. Fever and temperatures exceeding 39 degrees C were more frequent in children shedding subgroup II rotaviruses, whereas vomiting was more pronounced in children with subgroup I infection. Diarrhea, dehydration, duration of illness, and the need for admission to a hospital ward were similar in both groups.

The molecular epidemiology of rotavirus infections in black infants in Ga-Rankuwa, South Africa, was investigated by polyacrylamide gel electrophoresis. Between 1983 and 1986, 14 different RNA electrophoretic patterns were observed for children with acute gastroenteritis. These electrophoretypes showed a sequential pattern of appearance, with a limited number being present at any one time. In contrast, for neonates only one RNA electrophoretype was detected, which persisted for at least 3 years.

A prospective 3-year study for enteric pathogens associated with diarrhoea in children was undertaken at Ga-Rankuwa Hospital, South Africa. Rotavirus was the most commonly isolated pathogen (24%), showing a marked seasonal distribution, with an autumn peak in activity. Enterotoxigenic and enteropathogenic Escherichia coli were frequently identified, and Salmonella, Shigella and Campylobacter were also isolated. Cryptosporidium and Giardia lamblia were the most frequently seen parasites. Rotavirus, E. coli, Salmonella and Campylobacter occurred predominantly in children less than 1 year old, whilst Shigella and the parasites were prevalent at all ages.

The means by which estrogen retards atherosclerosis cannot be explained solely by changes in circulating lipoprotein levels. We studied the effects of 17 beta-estradiol on the binding, incorporation, and degradation of low density lipoprotein (LDL) by cultured bovine aortic endothelial cells (BAEC). Estrogen receptors in the cytoplasm and nucleus of BAEC could be demonstrated by immunofluorescent staining. Estradiol was found not to affect surface binding of LDL to BAEC. However, at physiologic concentrations (50 pg/ml), estradiol did enhance LDL uptake by the BAEC (P less than 0.005). This enhancement was present but somewhat reduced at higher concentrations of estrogen (P less than 0.05). Only approximately 10% of incorporated LDL was trichloroacetic acid soluble, indicating a low rate of LDL degradation. The relative rate of LDL breakdown within the BAEC was not altered by estrogen. These results, showing estrogen stimulation of LDL uptake by the BAEC, do not clarify the protective effect of this hormone. It is speculated that estrogen may augment the cellular clearance of LDL.

A continuously growing cell line has been established from autopsy material taken from a primary liver carcinoma, a cancer which has a high incidence in Southern Africa. The cell line was initiated from multifocal areas of outgrowth in the primary culture, and adaptation to in vitro conditions was completed after 18 months. The cells resemble hepatocytes in culture, have a doubling time of 35-40 hours and a plating efficiency of 40-50%. No virus particles have been found in the cells by ultrastructural examination. The isozyme pattern and the karyology of the cells are human. The chromosome pattern is heteroploid (mean number 56) and there are marker chromosomes.

The properties of a new cell line derived from a human retroperitoneal liposarcoma are described. The cells do not grow at low cell concentrations and contain in their cytoplasm large numbers of droplets that stain with Oil Red O. No indication of the presence of endogenous virus particles could be found. The mean chromosome number per cell is 36, with several constant markers, the most conspicuous of which is a large submetacentric marker due to a translocation between chromosomes 4 and 11, which is present in every cell. The liposarcoma cells show an enhanced uptake of [14C]acetate compared to normal human fibroblasts.

A case illustrating fracture and translocation of a Kim-Ray Greenfield filter strut due to intraoperative manipulation of the filter during cholecystectomy is presented. Awareness of this previously unreported complication is essential in preventing its occurrence.

The Alexander hepatoma cell line, PLC/PRF/5, was studied for evidence of hepatitis B virus markers and alpha-fetoprotein. Only hepatitis B surface antigen and alpha-fetoprotein were detected. Induction experiments with 5-iodo-2'-deoxyuridine and inoculation of chimpanzees with whole cells or tissue culture fluid did not reveal evidence of synthesis of additional hepatitis B virus markers or of production of infectious virus.

An oesophageal carcinoma cell line was karyotyped at passages 8,48,64 and 88. It showed a persistent loss of D group chromosomes and subtelocentric, acrocentric, dicentric and other markers were frequently present. During 80 passages the modal number declined from 60,5 to 54,09. The chromosome pattern of a hepatoma cell line was studied at passages 15/17 and 28. It showed a loss of D and G group chromosomes and the presence of various markers including a D/G fusion.