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Biomedical subjects

S D Colquhoun

Publications and source records attributed to S D Colquhoun.

27 records · Page 2Linked to original sources
PubMed1993

IL-4 inhibits IL-2 induction of LAK cytotoxicity in lymphocytes from a variety of lymphoid tissues.

The purpose of this study was to determine the influence of recombinant human interleukin-4 (IL-4) on the regulation of lymphokine-activated killer (LAK) and mixed lymphocyte culture cytotoxic activity. Lymphocytes from several lymphoid tissues were studied including human peripheral blood leukocytes (PBL), spleen cells, thymocytes, and thoracic duct lymphocytes. Cells were cultured with IL-4 in the presence or absence of recombinant human interleukin-2 (IL-2) in 4-day cultures. LAK and natural killer (NK) activities were measured in a standard chromium release cytotoxicity assay against LAK-sensitive, NK-resistant M14 melanoma targets and NK-sensitive K562 erythroleukemic cells. IL-4 alone does not increase NK or LAK activity under the conditions studied. However, IL-4 does inhibit the induction of cytotoxic activity by IL-2. IL-4 inhibits IL-2-induced thymidine incorporation in 3-day PBL cultures, suggesting that the inhibition of cytotoxicity is not a dilution effect due to the proliferation of noncytotoxic cell populations. IL-4 also inhibits the development of LAK and NK-like activities generated in mixed lymphocyte culture (MLC) while augmenting MLC-generated allospecific cytotoxic T lymphocyte activity. Thus, IL-4 appears to inhibit the induction of nonspecific cytotoxic effectors while augmenting the generation of MHC-specific responses. This confirms an important regulatory function for this lymphokine in the generation of cytotoxic effectors.

Cell Division↗
PubMed1993

Celiac compression syndrome and liver transplantation.

OBJECTIVE: The authors assessed the prevalence and clinical significance of the celiac compression syndrome in liver transplantation patients. SUMMARY BACKGROUND DATA: Compression of the celiac axis by the median arcuate ligament of the diaphragm, causes a decrease in celiac artery blood flow which may lead to hepatic artery thrombosis in patients undergoing orthotopic liver transplantation. METHODS: From July 1991 to July 1992, 17 (10%) cases of celiac compression syndrome were identified among 164 consecutive adult patients who underwent liver transplantation. The diagnosis was confirmed by blood flow recording demonstrating a typical pattern of accentuated decrease in celiac blood flow during expiration. RESULTS: Surgical transection of the median arcuate ligament resulted in normalization of the hepatic artery blood flow. In two cases (11.7%), an interposition iliac graft from the recipient supra-celiac aorta was used for the arterial reconstruction. During the follow-up period of up to 15 months, there was no incidence of hepatic artery thrombosis. CONCLUSIONS: The clinical significance of the celiac compression syndrome is evident in liver transplantation in which the collateral circulation to the liver is compromised and the celiac artery remains the only source of arterial blood. It is imperative to identify and remove the obstruction of the celiac axis to prevent severe complications and potential graft loss.

Adult↗
PubMed1992

Biliary strictures complicating liver transplantation. Incidence, pathogenesis, management, and outcome.

Six hundred sixty-six patients received 792 liver transplants between February 1, 1984 and September 30, 1991. Biliary reconstruction was by choledochocholedochostomy (CDCD) with T-tube (n = 509) or Roux-en-Y choledochojejunostomy (CDJ) (n = 283). Twenty-five patients (4%) developed biliary strictures. Anastomotic strictures were more common after CDJ (n = 10, 3.5%) than for CDCD (n = 3, 0.6%). Intrahepatic strictures developed in 12 patients. Six patients had occult hepatic artery thrombosis (HAT). The other six patients received grafts in which cold ischemia time exceeded 12 hours. Anastomotic strictures were successfully managed by percutaneous dilation (PD) in five patients (n = 10), operation in three (n = 6), with retransplantation required in two patients. Intrahepatic strictures were managed by PD in seven, retransplantation in one, and expectantly in four patients. Of 25 patients, 19 (76%) are alive with good graft function. In three of six deaths, the biliary stricture was a significant factor to the development of sepsis and allograft failure. The authors conclude that (1) anastomotic strictures are rare after LT; (2) the development of biliary strictures may signify occult HAT; (3) PD is effective for most strictures; and (4) extended cold graft ischemia (less than 12 hours) may be injurious to the biliary epithelium, resulting in intrahepatic stricture formation.

Adult↗
PubMed1991

Role of percutaneous fine-needle aspiration biopsy in suspected intrathoracic malignancy.

Percutaneous fine-needle aspiration (PFNA) biopsy is an accepted technique for the diagnosis of suspected intrathoracic malignancy, but the appropriate indications for its use have not been clearly defined. To help establish guidelines, we performed a retrospective analysis of 188 patients who underwent PFNA biopsy for suspected intrathoracic malignancy. Biopsy led to a diagnosis in 72% (135/188) of the patients, but in 27% (50/188) samples were inadequate for cytological diagnosis, and in 2% (3/188) samples were adequate but failed to yield a diagnosis. Fifty-three patients underwent surgical intervention, thus allowing histological confirmation of the cytological diagnosis. In patients with a diagnosis from PFNA biopsy, operation confirmed malignancy in 97% (37/38) and a specific cell type in 79% (30/38). In patients without a diagnosis after biopsy, a malignancy was found in 73% (11/15) at the time of operation. This suggests a high rate of accuracy when PFNA biopsy provides a diagnosis. However, it also illustrates that a substantial percentage of PFNA biopsy attempts fail to yield a diagnosis in patients ultimately found to have malignancies. This implies that PFNA biopsy might best be reserved for patients who are not surgical candidates.

Adenocarcinoma↗
PubMed1988

Interleukin-1 and tumor necrosis factor production by tumor-associated mononuclear leukocytes and peripheral mononuclear leukocytes in cancer patients.

The production of interleukin-1 (IL-1) and tumor necrosis factor (TNF) by tumor-associated mononuclear leukocytes (TAML) and peripheral mononuclear leukocytes (PMBL) from 9 otherwise untreated patients with a variety of malignancies (lung, sarcoma, stomach, renal) was assessed. Cells were cultured for 24 hr in vitro in the presence or absence of lipopolysaccharide (LPS), and IL-1 and TNF levels were measured in culture supernatants. TNF production was comparable between TAMLs and PBMLs. However, a striking defect in IL-1 production by TAMLs was noted. There was no basal production of IL-1 and LPS-stimulated TAMLs produced only 1% the amount of IL-1 produced by LPS-stimulated PBMLs.

Biological Assay↗
PubMed1988

Effects of systemic recombinant interleukin-2 on natural killer and lymphokine activated killer activity of human tumor infiltrating lymphocytes.

The purpose of these studies was to compare local and systemic human lymphokine activated killer (LAK) and natural killer (NK) cytotoxicity and to determine its modulation by the systemic administration of recombinant interleukin-2 (rIL-2). After preoperative systemic rIL-2, we extracted tumor infiltrating lymphocytes (TIL) and peripheral blood lymphocytes (PBL) from patients with pulmonary tumors and compared pre- and posttreatment spontaneous NK activity and their response to in vitro rIL-2. Spontaneous TIL NK activity was increased in patients receiving 15,000 units/kg rIL-2 preoperatively [6.6 lytic units (LU)] compared to those receiving 1,000-10,000 units/kg (0.8 LU) or no rIL-2 (1.4 LU). After 3 days incubation with 1,000 units/ml rIL-2, TIL NK cytotoxic activity was increased in patients receiving 15,000 units/kg rIL-2 (65.4 LU) compared to those receiving 1,000-10,000 units/kg (6.0 LU) or no treatment (24.9 LU). Spontaneous TIL LAK activity was low overall (1.1 LU) with the exception of two patients receiving 15,000 units/kg who had 3.1 and 3.7 LU spontaneously. TIL LAK precursor activity was only slightly increased in patients receiving 1,000-10,000 units/kg rIL-2, whereas those receiving 15,000 units/kg rIL-2 had an average of 22.8 LU. Systemic rIL-2 also increased spontaneous PBL NK activity. Reincubation of PBL obtained at time of surgery or 3 days after discontinuing systemic rIL-2 resulted in significant increases in cytotoxic response to in vitro rIL-2 compared to pre-IL-2 in vitro responses. Systemic rIL-2 had no effect on spontaneous PBL LAK activity. Thus, the immunosuppressive tumor environment can be partially reversed with 15,000 units/kg systemic rIL-2. Higher doses of systemic rIL-2 also increased spontaneous PBL NK activity at time of surgery and 3 days after discontinuing rIL-2. Both TIL and PBL inducible cytotoxicity were boosted in vitro following higher doses of systemic rIL-2.

Humans↗