Multiple myeloma and human immunodeficiency virus-1 (HIV-1) infection.

Multiple myeloma (MM) in three human immunodeficiency virus (HIV)-infected patients is reported. HIV infection predisposes to the development of high-grade B-cell lymphomas, but few cases of plasma cell tumours in association with HIV have been reported. The coincidence of HIV infection and neoplasia highlights the distinct roles of immunodeficiency and infection with herpesviridae, including HIV itself, in the pathogenesis of HIV-related tumours. In addition, a number of cytokines (e.g., interleukin-6 [IL-6]) and angiogenic factors (e.g., vascular endothelial growth factor [VEGF] and basic fibroblastic growth factor [bFGF]) may play a role in the initiation, maintenance, and progression of multiple myeloma (MM). Infection was the first clinical consideration to the cause of the illness in two of our HIV-seropositive patients. The diagnosis of MM may be difficult in patients with advanced HIV infection as they often have renal failure, bone marrow plasmacytosis, repeated infections, and polyclonal hypergammaglobulinaemia, due to HIV infection itself, opportunistic pathogens, and/or medication.

Evidence for horizontal and not vertical transmission of human herpesvirus 8 in children born to human immunodeficiency virus-infected mothers.

A survey of antibody responses to human herpesvirus 8 (HHV-8) was undertaken to examine the mode of transmission of this virus to children born to mothers with HIV. Methods. Serum samples from a cohort of 92 mother-infant pairs and a cross-sectional cohort of 100 children (median age, 4 years) were tested. In the cohort of mother-infant pairs, 14 infants were HIV-infected, 72 were not and the HIV status was unknown for 6. In the cohort of children 70 were HIV-infected and 30 were vertically exposed but uninfected. Serologic responses to two HHV-8 antigens, latency-associated nuclear antigen and the structural antigen encoded by open reading frame 65 were detected by immunofluorescent antibody test and enzyme-linked immunoassay. Results were confirmed by Western blot. Results. All HHV-8-seropositive mothers were African (17 of 92, 18.5%). Six of their infants were HHV-8-seronegative and 11 had at least 1 HHV-8-seropositive sample. One of the 11 infants tested only at birth had a lower antibody titer than the mother; the remaining 10 infants had decreasing titers up to 7 months of age and 6 became seronegative. No infants born to HHV-8-seronegative mothers had antibodies to the virus. The seroprevalence to HHV-8 was 6% in the cohort of children. All had African mothers and their median age was greater than that of the cohort (8.4 vs. 4.0 years). Five were coinfected with HIV. Conclusions. HHV-8 was not vertically transmitted by any of the HIV-coinfected mothers. Acquisition of antibody to HHV-8 occurred in older children, implying a horizontal route of transmission.

No evidence of pig DNA or retroviral infection in patients with short-term extracorporeal connection to pig kidneys.

BACKGROUND: The xenotransplantation of organs and tissues, in particular those from pigs, is viewed as a means to alleviate the shortage of human donor organs and cells available for transplantation and also as a therapy for other diseases. The potential microbiological hazards of xenotransplantation have recently attracted much attention. One concern is over pig endogenous retroviruses (PERV). Until the possible consequences of infection by PERV are better understood it is unlikely that a significant number of porcine xenotransplants will proceed. However, a small number of patients have already been treated with or exposed to living porcine cells or tissue, and investigation of these patients may provide valuable information. METHODS: We took serial blood samples from two renal dialysis patients whose circulation had been linked extracorporeally to pig kidneys and tested them for pig DNA and PERV DNA by nested PCR. The patients' plasma was also tested for neutralising antibodies to two anthropotropic PERV strains. FINDINGS: Having established that the nested PCRs could detect single molecules of target sequence, we analysed DNA isolated from patients' peripheral blood mononuclear cells. We found no evidence of pig or PERV DNA in either patient, even in samples taken as early as 6 h after the perfusion. Furthermore, we found no evidence of seroconversion for PERV-specific antibodies. INTERPRETATION: The absence of porcine cells in the circulation of both patients, even in the samples taken soon after the perfusion experiment, suggests that any porcine cells dislodged from the kidney became rapidly sequestered from the circulation. Since cell-to-cell contact increases the efficiency of infection of PERV this removal of porcine cells may increase the risk of transmission of PERV to the xenograft recipient. We did not, however, detect indications of infection by PERV by PCR or neutralisation assay. The genetic and serological methods described here will be useful for detection of possible PERV infection in other patients.

Effect of peripheral versus portal venous administration of insulin on postprandial hyperglycemia and glucose turnover in alloxan-diabetic dogs.

The effects of peripheral venous and portal venous delivery of insulin by a closed-loop insulin infusion device (Biostator GCIIS) on postprandial hyperglycemia and rates of glucose appearance, disappearance, and clearance were compared in alloxan-diabetic dogs. The amounts of insulin required and the peripheral venous plasma insulin concentrations achieved were not different for the two routes of insulin administration. No statistically significant differences in postprandial hyperglycemia or patterns of glucose disposal were observed between the two routes of insulin delivery. These studies indicate that in terms of hepatic versus extrahepatic disposal of glucose, there appears to be no practical advantage of portal venous over peripheral venous administration of insulin when a closed-loop insulin infusion device is used.

Pancreatic immunoreactive somatostatin release.

The location of the somatostatin-containing D-cells of the pancreatic islets between the A- and B-cells suggests that their function might be to inhibit insulin and/or glucagon secretion by these neighboring cells. To determine if insulin and/or glucagon, in concentrations that might be present in the extracellular space surrounding the D-cells, stimulate immunoreactive somatostatin (IRS) release, we perfused 10 microng of glucagon or 10 milliunits of insulin per ml in 11 isolated dog pancreases, for 40 min in seven experiments and for 100 min in four experiments. In eight of the nine experiments in which glucagon was perfused, a prompt and significant rise in mean IRS release, ranging from 71 to 128% above the control level, was observed. In the eight experiments in which insulin was perfused. IRS did not increase during the first 40 min; in the two 100-min insulin experiments, it did rise during the final 50 min, however. To determine the effect of an A- and B-cell secretogogue on IRS release, we perfused 20 mM arginine for 60 min in six experiments. In all, IRS rose within 3 min and reached a level 71-465% above the control, remaining significantly elevated throughout the perfusion, while glucagon and insulin rose to peak levels at 2 min and then declined somewhat despite continuing arginine perfusion. The results indicate that perfusion of the normal dog pancreas with high doses of glucagon or arginine is accompanied by a prompt increase in IRS release and are compatible with a local feedback circuit involving A- and D-cells. Insulin appears not to augment IRS release, at least not promptly, but IRS stimulated by local endogenous glucagon could inhibit the B-cell response to locally secreted glucagon and thereby influence the composition of the insulin/glucagon secretion mixture.

Demonstration of gastric glucagon hypersecretion in insulin-deprived alloxan-diabetic dogs.

The contribution of the gastric fundus to the hyperglucagonemia of poorly controlled diabetes was studied in insulin-deprived alloxan-diabetic dogs by simultaneously measuring plasma glucagon in the venous effluents of the fundus and the pancreas, and the inferior vena cavae plasma. In the basal state, mean glucagon averaged 411 +/- 45 pg./ml. in the gastric vein and 941 +/-161 in the pancreaticoduodenal vein; both values were significantly above the vana caval level of 281 +/-35 (p less than 0.01). Intravenous arginine infusion to 1,180 +/- 432 after 1.5 minutes; this was significantly above the mean vena caval glucagon concentration which reached a peak of only 352 +/- 74 (p less than 0.01 to 0.05). Intragastric instillation of arginine was followed by a doubling of gastric vein glucagon within 10 minutes, and the increases in the gastric vein were significantly greater than in the peripheral plasms at several points. The infusion of insulin at a rate of 0.0015 u./kg./min. rapidly lowered glucagon in the gastric and pancreaticoduodenal veins, abolishing the gradient across the stomach and reducing the transpancreatic gradient. The studies raise the possibility that extrapancreatic glucagon may contribute to the hyperglucagonemia of insulin deficiency.

Gastric A-cell function in insulin-deprived depancreatized dogs.

To determine if gastric A-cells are a major source of the glucagonemia of insulin-deprived depancreatized dogs and to examine their secretory behavior, immunoreactive glucagon (IRG) was measured simultaneously in plasma from the inferior vena cava (VC) and from a gastric vein (GV) draining the fundus. Basal GV IRG averaged 205 +/- 35 pg/ml, significantly above the VC level of 71 +/- 30 (P less than 0.001) and rose to 1417 +/- 498 1.5 minutes after the start of an arginine infusion, exceeding VC IRG at all points (P less than 0.01). Measurement of IRG in gastric, jejunal, and ileal veins and vena cava revealed an IRG gradient only across the stomach. Measurement of glucagon-like immunoreactivity (GLI) revealed no gradient across the stomach, jejunum, or ileum, thus excluding cross-reaction with GLI as the cause of the GV hyperglucagonemia. Intragastric arginine elicited a near doubling of GV IRG within 1.5 minutes and this persisted for at least 120 minutes, ranging from 142 to 623 pg/ml above the VC level. Infusion of insulin at a physiologic rate lowered GV IRG from 665 +/- 66 to 151 +/- 49 pg/ml in 20 minutes and abolished the GV-VC gradient within 60 minutes, whereas intravenous and intragastric glucose administration without insulin did not alter GV IRG. It is concluded that: 1) in the insulin-deprived depancreatized dog, the stomach is a major source of IRG; 2) gastric IRG secretion is somehow stimulated by intravenous and intragastric arginine administration; 3) it is not influenced by intravenous or intragastric glucose administration; and 4) its release is suppressed by physiologic levels of insulin.

Gastric A-cell function in normal dogs.

Glucagon release from the gastric fundus and pancreas were compared in normal dogs by measuring glucagon in plasma from a major gastroepiploic vein, the superior pancreaticoduodenal vein, and the inferior vena cava. In 32 dogs in the basal state, gastric vein glucagon averaged 97 +/- 40 pg/ml, not significantly different from the 93 +/- 41 pg/ml level in the vena cava. Pancreaticoduodenal vein glucagon averaged 250 +/- 32 pg/ml (P less than 0.001). Intravenous arginine infused in four dogs caused a rise in mean gastric vein glucagon to 210 +/- 33 pg/ml within 3 min, and glucagon remained between 53 and 98 pg/ml above the vena caval level thereafter. In the gastric vein, the rise in glucagon was significantly greater than in the vena cava at 3, 5, and 10 min (P less than 0.05), but was far less than in the pancreaticoduodenal vein where glucagon rose to 1,295 +/- 379 pg/ml at 1.5 min. Evidence of modest gastric glucagon release was observed after the intragastric instillation of arginine, but not during insulin or phloridzin-induced hypoglycemia. It was concluded that in normal dogs under the circumstances studied, the gastric fundus is not a major source of circulating glucagon.