The college viewpoint

Our changing health care environment presents new challenges to the surgical profession. This article examines those concerns, including strains on surgeons' professional values, financial pressures resulting from federal laws and regulations, the expansion of managed care, and demands for improved continuing education opportunities. This article illustrates how the American College of Surgeons has been helping surgeons cope with the shifts in balance taking place around them. It further highlights how the American College of Surgeons is moving forward in all areas of concern to surgeons by promoting standards for surgical care, educating third-party payors about the effects of financial constraints, expanding its educational programs, and seeking innovative methods to fulfill its mission.

Endodontic pathogens stimulate monocyte chemoattractant protein-1 and interleukin-8 in mononuclear cells

Microbial infection of the dental pulp leads to the recruitment of leukocytes and the formation of lesions of endodontic origin. The chemokines interleukin-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1) are relatively specific chemoattractants for neutrophils and monocytes, respectively. In the present studies, peripheral blood mononuclear cells were stimulated by Streptococcus mutants, Porphyromonas endodontalis, and Peptostreptococcus anaerobius, which are associated with lesions of endodontic origin. Each of these bacteria induced a dose-dependent increase in IL-8 and MCP-1, determined by ELISA. The levels induced are physiologically relevant. However, low doses of P. endodontalis were less effective in inducing IL-8 or MCP-1 expression, compared with S. mutants or P. anaerobius. Thus, these bacteria can induce significant levels of the chemokines IL-8 and MCP-1, which could contribute to the recruitment of neutrophils or monocytes in vivo. The expression of these mediators may contribute to the development of endodontic infections, particularly with regard to inflammatory leukocyte recruitment.

A whole blood alternative to traditional methods for CD4+ T lymphocyte determination

Flow cytometry, the method of choice for determining subset cell populations, requires sophisticated instrumentation and highly trained operators. An alternative method for subpopulation determinations is presented that is fast, simple, and readily interpreted for absolute subset counts. This method uses antibody labeled microspheres added to whole blood and after lysing, read on a hemocytometer using an ordinary light microscope. The total time of testing is less than 10 min with results comparable to that obtained using a flow cytometer and a hematology analyzer to calculate absolute subpopulation values. This method is demonstrated for CD4+ lymphocytes which have considerable value in following HIV-infected individuals.

A simple and rapid method for removal of specific cell populations from whole blood

A method is presented in which specific cells can be rapidly separated from whole blood by the use of antibody labelled dense particles utilizing gravity as a means of separation. This method specifically removes the targeted cells with minimal non-specific cell loss. The method is simple to perform and rapid, requiring less than 10 min for cell/particle binding and separation. The method is robust so that exact ratios of particles to cells are not needed. This method could be used in any separation scheme to remove specific cell populations without significant modification.

Monocyte chemoattractant protein 1 and interleukin-8 production in mononuclear cells stimulated by oral microorganisms

Chemokines are a family of low-molecular-weight proinflammatory cytokines that stimulate recruitment of leukocytes. The chemokines interleukin-8 (IL-8) and monocyte chemoattractant protein 1 (MCP-1) are relatively specific chemoattractants for neutrophils and monocytes, respectively. Chemokine expression contributes to the presence of different leukocyte populations observed in normal and pathologic states. In the present studies, peripheral blood mononuclear cells (PBMC) were stimulated by microbes (Candida albicans, Streptococcus mutans, Porphyromonas gingivalis, and Actinobacillus actinomycetemcomitans) selected based upon their importance as oral pathogens. IL-8 and MCP-1 gene expression and protein release were determined by Northern blot (RNA blot) analysis and enzyme-linked immunosorbent assay. C. albicans, P. gingivalis, and A. actinomycetemcomitans induced high levels of production of both MCP-1 and IL-8. S. mutans was a strong inducer of MCP-1, but it did not stimulate significant production of IL-8. C. albicans, S. mutans, and A. actinomycetemcomitans were 500 to 5,000 times more potent than P. gingivalis in terms of MCP-1 production. In general, the microbe-to-PBMC ratios required for maximum gene expression of MCP-1 were lower than those for IL-8. However, for actual protein release of MCP-1 versus IL-8, differences in the effects of various microbe concentrations were observed only for A. actinomycetemcomitans. These results demonstrate that different oral pathogens induce specific dose-dependent patterns of chemokine gene expression and release. Such patterns may help explain the immunopathology of oral infections, particularly with regard to inflammatory leukocyte recruitment.

Flow cytometric immunofluorescence and DNA analysis: using a 1.5 mW helium-neon laser (544 nm)

We evaluate a 1.5 mW HeNe laser (544 nm) for use on an EPICS Elite with a 76 microns Sortsense flow cell. The two applications chosen were immunofluorescence and DNA analysis. We measured the fluorescence threshhold of phycoerytherin calibration beads to be approximately 336 MESF. Cell analysis with a HeNe laser and Argon laser correlated well for the CD4PE, CD56PE, CD19PE conjugates, with correlation coefficients of 0.98, 0.99, 0.94, respectively. The % positive and mean channel fluorescence were comparable to the results obtained with a 15 mW Argon laser. In addition, a three-color configuration yielded excellent results. Cell analysis of CD4PE, CD3ECD and CD19Cy-Chrome with the HeNe laser and Argon laser correlated well with correlation coefficients of 0.96, 0.95, and 0.92, respectively. The histograms showed good separation between the negative cells, the dimly staining cells and the brightly staining cells. Propidium Iodide was chosen for DNA analysis. Full CV values for whole blood DNA fluorescence using the green laser were good at 2.6%. These data indicate the low power 544 nm laser is sufficient to do immunophenotyping and DNA analysis. Results may be explained by higher quantum efficiency and lower background fluorescence. The wavelength of the 544 nm laser is much closer to the excitation peaks of PI, PE, and the tandem dyes ECD and Cy-Chrome. Also, the Raman scattering of water for the 544 nm laser has a longer wavelength maximum than the emission peaks of PI, PE, and ECD. The major advantages of this laser for the research laboratory are small size, no cooling fan, low power requirements and low cost.

Lymphocyte subset determination using a hematology analyzer

Anti-CD4 antibody (T4)-coated microspheres were used to label CD4 cells in whole blood. The mixture was lysed and analyzed by a modified Coulter VCS hematology analyzer, which differentiated microsphere-labeled cells by a change in Coulter volume, conductance, and light scatter. %CD3+/CD4+ fluorescent values from a profile were compared to %CD4 values using the VCS-microsphere method. CD3 gating was used to exclude CD4+ monocytes from the 90LS-FALS lymphocyte gate. The results correlated well (R = 0.996). The percentage of CD4+ lymphocytes from profile scatterplots and VCS scatterplots showed a line of regression close to the equivalence line (n = 76, slope = 0.96) when CD3 gating was used for the profile. These results suggest that CD3 gating, though necessary for 90LS-FALS scatterplots, may not be necessary for volume-conductance-light scatterplots.

Comparison of transjugular and surgical portosystemic shunts on the outcome of liver transplantation

OBJECTIVE

To analyze the effect of previous transjugular intrahepatic portosystemic shunt (TIPS) vs surgical portosystemic shunt (SPS) on the outcome of orthotopic liver transplantation (OLT).

DESIGN

A case series of 38 patients who underwent OLT: 25 with a previous TIPS and 13 with a previous SPS.

SETTING

A liver transplant center and interventional radiology service in a private, tertiary referral medical center.

PATIENTS

Eighteen men and seven women who had a TIPS before OLT were compared with nine men and four women who had an SPS before OLT.

MAIN OUTCOME MEASURES

Operative transfusion requirements, operative time, length of hospital stay, postoperative liver chemistry studies, and graft and patient survival.

RESULTS

Compared with patients who had an SPS, patients who had a TIPS had significantly less median transfusion requirements for packed red blood cells (5 vs 12 U), fresh-frozen plasma (0 vs 8 U), and thrombocytes (0 vs 1 U). The median operative time (9 vs 13 hours), length of intensive care unit stay (3 vs 5 days), and length of hospital stay (12 vs 24 days) were also significantly less in patients who had a TIPS. The 2-year actuarial patient survival rate was 92% in both groups.

CONCLUSIONS

In patients undergoing OLT, TIPS is associated with reduced operative transfusion requirements, operative time, and length of intensive care unit and hospital stays compared with SPS. In the potential liver transplant candidate with refractory complications of portal hypertension, TIPS is preferred to SPS.

Emergent abdominal surgery in AIDS: experience in San Francisco

Several recent reviews have suggested that aggressive surgical intervention can reduce morbidity and mortality associated with intra-abdominal crises in AIDS patients. We reviewed our experience with 57 AIDS patients with 63 emergent laparotomies performed at 4 hospitals affiliated with the University of California in San Francisco. Fifty-five patients (96%) were homosexual men. Thirty-nine (68%) had been treated for an opportunistic infection. Indications for exploration included right lower quadrant pain consistent with appendicitis in 24 patients (38%), visceral perforation or obstruction in 11 (17%), right upper quadrant pain in 9 (14%), diffuse peritonitis in 8 (13%), and uncontrollable hemorrhage in 8 (13%). Perioperative mortality was 12% (7/57). Fifteen patients (26%) suffered major complications including pneumonia, sepsis, multi-organ failure, and intra-abdominal abscess. Forty-five of 50 survivors (90%) were receiving some type of chronic antimicrobial or antineoplastic chemotherapy, compared to only 2 of the 7 patients who died (28.6%) (P < 0.001). Lack of ongoing prophylactic treatment for AIDS-related disease, active opportunistic infections, Walter Reed VI classification, and ongoing sepsis at the time of exploration were noted to be associated with increased morbidity and mortality.

Autologous fibrin glue in the treatment of rectovaginal and complex fistulas

This nonrandomized series reports the use of autologous fibrin glue to treat complex rectovaginal and anorectal fistulas. The use of an autologous source to prepare fibrin glue eliminates the risk of disease transmission. Ten patients, six women and four men, with complex fistulas were treated with autologous fibrin glue application. Five patients had rectovaginal fistulas; one of them had Crohn's disease. Five patients had complex anal fistulas; two of them had Crohn's disease, and one had a large postanal ulcer associated with HIV disease. All patients had outpatient preoperative mechanical bowel preparation and prophylactic parenteral antibiotics. Six of the ten patients (60 percent) reported complete healing of the fistulas. Follow-up ranged from three months to one year. Four of five rectovaginal fistulas healed. The two patients with Crohn's disease and complex anal fistulas and the patient with HIV disease did not heal, but all three reported significantly less drainage. Autologous fibrin glue is a viable alternative for the treatment of recurrent rectovaginal and complex abscess/fistulas.

Adenocarcinoma of the anal glands. Results of a survey

Anal gland adenocarcinoma is rare, with information concerning this lesion communicated mostly as case reports. Cases seen by authors, combined with a survey of the membership of The American Society of Colon and Rectal Surgeons, allowed 52 cases with sufficient data for analysis. It became clear from the survey that most colorectal surgeons have not treated this malignancy. Predominant symptoms are anal pain (58 percent), rectal bleeding (40 percent), and the presence of perianal mass (37 percent). Fifty-four percent of patients present with a fistula, the incidence of fistula being significantly higher in males. Metastases, which may be inguinal, pelvic, or hepatic, are present at diagnosis in 13.5 percent of patients. Three-fourths of patients are eventually treated by abdomino-perineal resection (APR). Twelve percent of the patients in this series had an APR after a failed local excision. The conclusions from this study are: 1) if local excision is attempted, it must be complete, and the patient must be followed closely for many years, and 2) APR is needed in most patients for local control, with the role of subsequent radiation therapy and/or chemotherapy not yet defined.

Appendicitis in acquired immunodeficiency syndrome

Reports in the surgical literature are few regarding common intra-abdominal disease processes, such as gallstone disease or appendicitis, in patients with AIDS and instead have focused on AIDS-related intra-abdominal diseases that infrequently require surgical intervention unless complicated by bleeding, obstruction, or perforation. A literature review for appendicitis in AIDS patients revealed only 30 well-documented cases drawn from 13 studies, with a 40% perforation rate and frequent delays and errors in diagnosis. A 7-year experience with 28 patients with appendicitis and AIDS from 4 urban San Francisco hospitals is reviewed. There were no perioperative deaths and an 18% postoperative complication rate. Five patients (18%) were found to have normal appendices with other intra-abdominal pathology, and an AIDS-related etiology for appendicitis was discovered in 7 of 23 patients with appendicitis (30%). With the exception of diffuse versus localized abdominal pain, no preoperative symptom or sign was useful in differentiating AIDS-related and non-AIDS-related disease. Aggressive use of ultrasound and abdominal computed tomographic scanning, along with early surgical intervention, is recommended.

The impact of liver reductions in pediatric liver transplantation

Reduced-size liver transplantation (RSLT) in children was introduced to alleviate a shortage of small-organ donors. The impact of RSLT on the waiting time for an organ and on morbidity and mortality was investigated. Between March 25, 1988, and August 11, 1990, 61 hepatic transplantations were performed in 55 children at the Pacific Transplant Institute in San Francisco, Calif. Full-size liver transplantation was performed in 41 cases and RSLT in 20 cases. The overall 30-month actuarial patient and graft survival rates were 89% and 73%, respectively. A comparison between full-size liver transplantation and RSLT showed no difference in patient and graft survival, reoperations, infections, or rejection. Benefits of RSLT were an increase in the donor pool size, a decrease in waiting time for a suitable donor, and a decrease in the rate of arterial thrombosis. The main morbidity of RSLT was an increase in perioperative blood requirement. We conclude that RSLT offers small children with end-stage liver disease a chance for long-term survival.

Gastrointestinal tuberculosis. Report of four cases

Gastrointestinal tuberculosis is a rare disease in the United States. Correct identification is often delayed because it is not considered early on in the differential diagnosis. Four patients with gastrointestinal tuberculosis and the symptoms, diagnosis, complications, and treatment of the disease are discussed. Gastrointestinal tuberculosis should be considered in Asian immigrant patients who present with symptoms and signs of inflammatory bowel disease.

Hemorrhoidal banding. A warning

Band ligation of symptomatic internal hemorrhoids is a well-established and accepted outpatient procedure. The purpose of this paper is to alert the medical profession to potential complications and death following this procedure. Each of the four patients described in this report experienced pain and inability to urinate following banding. This report does not condemn banding but, rather, focuses on problems associated with a procedure perceived by many to be risk free.

Cyclic AMP effects on cell-to-cell junctional membrane permeability during adipocyte differentiation of 3T3-L1 fibroblasts

Mouse 3T3-L1 fibroblast cells, also know as preadipocytes, differentiate in vitro into adipocytes when treated with promoting agents and acquire numerous properties characteristic of mature fat cells. We studied junctional cell-to-cell communication by measuring the incidence of electrical coupling and transfer of carboxy-fluorescein among these cells. When 3T3-L1 cells were induced to differentiate into adipocytes, they lost virtually all cell-cell communication. Preadipocytes that remained nondifferentiated after the treatment maintained normal communication. Loss of communication in the adipocytes invariably coincided with appearance of lipid droplets and not with other phenotypic changes. In the differentiating cells, loss of cell-to-cell communication and lipid accumulation was prevented if dibutyryl cyclic AMP and caffeine were present in the culture medium. Addition of dibutyryl cyclic AMP and caffeine to already differentiated adipocytes resulted in loss of lipid and simultaneously improved junctional permeability. The results demonstrate that in the in vitro 3T3-L1 cell system, (a) cell-to-cell communication and lipid synthesis are intimately related during the adipose conversion and (b) cAMP affects the expression of the two phenotypes.

Purification of beta cells from rat islets by monoclonal antibody-fluorescence flow cytometry

Fluoresceinated monoclonal antibody plus flow cytometry was used to purify beta cells from mixed pancreatic islet endocrine cell populations. A2B5, a monoclonal antibody to a glycolipid on the surface of cells of neuroendocrine origin, was incubated with single cells dissociated from rat pancreatic islets. Antibody-bound cells were labeled with fluoresceinated goat F(ab')2 antimouse immunoglobulin and highly fluorescent cells were separated from less fluorescent cells on a Coulter EPICS IV cell sorter. Sorted cell populations were analyzed by radioimmunoassay for insulin, glucagon, and somatostatin. The highly fluorescent cell population was enriched sixfold for insulin-containing beta cells, indicating that islet beta cells are relatively enriched in A2B5 antigen and can be partially purified by this method.

Percutaneous gastrostomy. A new simplified and cost-effective technique

A refined endoscopically controlled percutaneous tube gastrostomy has been described in detail, and the experience gained in 28 patients has been reported herein. A majority of the patients had severe underlying neurologic disorders, malignancy of the oral pharynx or esophagus or chronic intestinal obstruction due to advanced malignancy. The three groups of patients were analyzed regarding mortality and morbidity. Three minor complications occurred in the entire group, and three in-hospital deaths occurred which were unrelated to the tube. In addition, four other patients died from their underlying disease several months after discharge from the hospital. Analysis of this technique has shown it to be safe, easy to perform, and acceptable to the patients and supporting personnel. A cost analysis showed significant savings when this technique was utilized instead of operative gastrostomy.

Percutaneous gastrostomy. A new simplified and cost-effective technique

A refined endoscopically controlled percutaneous tube gastrostomy has been described in detail, and the experience gained in 28 patients has been reported herein. A majority of the patients had severe underlying neurologic disorders, malignancy of the oral pharynx or esophagus or chronic intestinal obstruction due to advanced malignancy. The three groups of patients were analyzed regarding mortality and morbidity. Three minor complications occurred in the entire group, and three in-hospital deaths occurred which were unrelated to the tube. In addition, four other patients died from their underlying disease several months after discharge from the hospital. Analysis of this technique has shown it to be safe, easy to perform, and acceptable to the patients and supporting personnel. A cost analysis showed significant savings when this technique was utilized instead of operative gastrostomy.

Mitosis of contact-inhibited 3T3 preadipocytes precedes chemically induced differentiation into adipocytes

We studied the conversion of 3T3 cells into adipocytes in vitro after pulsed exposure of confluent, nongrowing cultures to various combinations of the "triggering" agents, methylisobutylxanthine, dexamethasone, and fetal calf serum. Conversion of nongrowing 3T3 preadipocytes into adipocytes takes place after the cells have been stimulated to undergo one round of cell division. Maximal cell division and cytodifferentiation occur only when all three triggering agents are present.

Rectalepidural fistula complicating Crohn's enterocolitis

A previously unreported complication of a patient with Crohn's enterocolitis and internal fistulation is presented. The patient presented with meningeal signs in the lumbosacral region, fever, and sepsis. Computerized axial tomography revealed air in the epidural space, and a presumptive diagnosis of rectalepidural fistula was made. Surgical management included a diverting end sigmoid colostomy and presacral drainage.

Ischemic colitis. Comparison of surgical and nonoperative management

A retrospective review of 18 patients with ischemic colitis is presented. Patients who developed ischemic colitis following abdominal aortic surgery were excluded, as were patients in whom the diagnosis was made on clinical grounds only. The diagnosis was confirmed in each case either by proctosigmoidoscopy, colonoscopy, barium enema, surgery, or autopsy. Nine patients were treated surgically and nine nonoperatively. The mortality in the operated group was 55 per cent, compared to a 45 per cent mortality in the nonsurgically managed patients. Successful treatment of ischemic colitis depends on early recognition, which requires a high index of suspicion for this common but frequently unrecognized entity.

Acquisition of an insulin-sensitive activity of adenosine-3',5'-monophosphate phosphodiesterase during adipose conversion of 3T3-L2 cells

Mouse 3T3-L2 fibroblasts differentiate when cultured and express a new phenotype which is characteristic of adipose cells. One aspect of this differentiation is the acquisition of hormone sensitivities typical of adipocytes. The sensitivity of adenosine-3',5'-monophosphate (cAMP) phosphodiesterase to brief insulin treatment in 3T3-L2 cells at various stages of adipose conversion was examined. The capacity to increase the activity of a low-Km form of the enzyme in response to acute insulin exposure is a property which is acquired as the cells begin to express the adipose phenotype. Enzyme activity in preadipocytes is not affected by inslin, nor is there an effect in the non-differentiating 3T3-C2 line under any of the conditions tested. Since insulin receptors and cAMP phosphodiesterase are both present in the preadipocytes, one result of this cytodifferentiation is to effectively couple receptors to the enzyme activity. Insulin-sensitive cAMP phosphodiesterase in 3T3-L2 adipocytes is characterized by a 40-50% increase in enzyme activity during insulin treatment when determined at 0.1 microM cAMP. This activation results from an increase in the apparent V of the enzyme and does not involve a change in enzyme-substrate affinity. Maximal stimulation is seen within 2-5 min and is sustained for at least 45 min when high levels of insulin (850 nM) are used. Lower concentrations of insulin (1.7 nM) also bring about rapid activation, although the activation is not completely sustained during longer incubations. Stimulated activity falls off to about 60% of peak values by 30 min. Re-addition of insulin after 30 min raises enzyme activity back to the maximal level. Further, the insulin response is completely reversible in that the insulin-sensitive cAMP phosphodiesterase activity disappears within 10 min after removal of insulin from the cultures.

Inhibition of adipose conversion in 3T3-L2 cells by retinoic acid

The role of retinoic acid in modulating the differentiation of 3T3-L2 fibroblasts into adipocytes has been examined. Results indicate that the retinoid is capable of effectively inhibiting the degree of adipose conversion which is brought about by treatment of preadipocytes with 1-methyl-3-isobutylxanthine plus dexamethasone. MOrphological and enzymatic (fatty acid synthetase activity) expression of the adipose phenotype are both inhibited more than 90% by 10(-6) M retinoic acid. The inhibition is concentration dependent with retinoic acid must be administered simultaneously with the triggering agents to be effective. Exposure of nongrowing preadipocytes to retinoic acid does not alter the ability o the cells to differentiate in response to a subsequent treatment with methylisobutylxanthine plus dexamethasone. Further, the inhibition is reversible. Cultures i which methylisobutylxanthine plus dexamethasone triggered differentiation has been blocked by addition of retinoic acid (10(-6) M) will readily undergo adipose conversion in response to a second treatment with methylisobutylxanthine plus dexamethasone in the absence of the retinoid. Similar inhibition of differentiation was found when cultures were treated with drugs in medium supplemented with either newborn calf serum or fetal calf serum. However, the extent to which methylisobutylxanthine plus dexamethasone are able to promote differentiation in these cells is considerably greater in medium containing fetal calf serum.

Differentiation of 3T3-L2 fibroblasts into adipose cells in bromodeoxyuridine-suppressed cultures

Growth of 3T3-L2 fibroblasts in medium containing 5-bromo-2'-deoxyuridine prevents the spontaneous cytodifferentiation of these cells into adipose cells. Treatment of bromodeoxyuridine-suppressed cultures at confluence with 1-methyl-3-isobutylxanthine, a promoter of the adipose conversion, results in differentiation of the fibroblasts into adipose cells but the extent of the conversion is less than that seen in cultures not treated with bromodeoxyuridine. 1-Methyl-3-isobutylxanthine appears to function without altering the amount of bromodeoxyuridine present in DNA.

Increase in fatty acid synthetase content of 3T3-L cells undergoing spontaneous and chemically induced differentiation to adipocytes

3T3-L fibroblasts differentiate into adipose cells when maintained in a non-growing state. The specific activity of fatty acid synthetase of differentiated cells was 25--30-fold higher than that present in 3T3-L fibroblasts or in 3T3-C2 cells that possess an extremely low incidence of differentiation to adipocytes. The results of immunochemical analysis indicate that the increased specific activity of fatty acid synthetase in the differentiated cells is due to an increase in the cellular content of this enzyme. The rate of conversion of adipose cells was accelerated by brief exposure of confluent non-growing cultures of 3T3-L cells to 3-isobutyl-1-methylxanthine. This was accompanied by an increase in the specificity activity of fatty acid synthetase, which was also shown to be due to an increase in the cellular content of this enzyme. The continuous presence of 3-isobutyl-1-methylxanthine in the culture medium was not required to elicit the morphological and biochemical changes in 3T3-L cells that occurred many days after the removal of the inducer but earlier than the onset of spontanous differentiation.

Modulation of granulopoiesis: opposing roles of prostaglandins F and E

CSF-dependent myeloid colony growth can be augmented or inhibited by a number of modulating factors. PGs of the E series are known to inhibit colony formation. The antagonistic actions of PGE and PGF in many biological systems prompted us to compare their effects on myelopoiesis in vitro. PGF2alpha at an optimal concentration of 1 x 10(-9)M increased colony formation by 50% over that stimulated by CSF alone. Similar augmentation was also observed from 16,16-dimethyl PGF2alpha, PGF1alpha, 6-keto PGF1alpha, and MIX. In contrast PGE1, PGE2, and 15(S),15-methyl PGE1 inhibited colony growth. Simulation by PGF reflected an absolute increase in granulocytic colonies, whereas inhibition by PGE affected both granulocyte and macrophage colony formation. The relative levels of PGE and PGF may play a determining role in the modulation of granulopoiesis.

Low rectovaginal fistulas. Approach and treatment

Experience with thirty-two patients with a low rectovaginal fistula with or without attendant sphincter damage is reported. The technic used is advancement of the anterior rectal wall with excision of the infected anal glandular tissue and repair of muscle tissue when indicated. Anorectal infection and childbirth injuries were the common causes. An acceptable recurrence rate was achieved. Colostomy was not used in this series.

Conversion of 3T3 fibroblasts into adipose cells: triggering of differentiation by prostaglandin F2alpha and 1-methyl-3-isobutyl xanthine

Green and Kehinde [(1974) cell 1, 113-116] have isolated clones of Swiss 3T3 fibriblasts that are able to convert to adipose cells. In this paper we report on two chemicals (prostaglandin F2alpha, 0.1 mug ml, and 1-methyl-3-isobutyl xanthine, 0.5 mM) that are able to rapidly and irreversibly program the fibroblasts to differentiate into adipose cells. Confluent cultures treated with prostaglandin F2alpha and insulin for 3-5 days, followed by insulin alone for 7-48 hr, yield numerous adipocyte colonies compared to control dishes and dishes treated with insulin alone. Cells treated with prostaglandin F2alpha or 1-methyl-3-isobutyl xanthine alone, rinsed, and then exposed to insulin gave similar results, indicating that the continuous presence of the triggering agent is not required to elicit the conversion of the fibroblasts to adipocytes. Agents that raise intracellular levels of 3':5'-cyclic AMP. 1.0 mM; 8-bromo-cyclic AMP,0.5 mM; and prostaglandin E1, 0.1 mug/ml) do not trigger the conversion process, suggesting that cyclic AMP may not be the mediator of differentiation in these cells. 8-Bromo-cyclic AMP, however, does induce thase; 3':5'-nucleotidohydrolase; EC 3.1.4.17) in these cells; the induction appears to be mediated by increases in intracellular cyclic AMP levels. These results indicate that this cell line might offer a system for studying the regulation of a type of cellular differentiation.

Guanylate cyclase and cyclic guanosine 3':5'-monophosphate phosphodiesterase activities and cyclic guanosine 3':5'-monophosphate levels in normal and transformed fibroblasts in culture

To investigate the role of guanosine 3':5'-monophosphate (cyclic GMP) in cultured cells we have measured guanylate cyclase and cyclic GMP phosphodiesterase activities and cyclic GMP levels in normal and transformed fibroblastic cells. Guanylate cyclase activity is found almost exclusively in the particulate fraction of normal rat kidney (NRK) and BALB 3T3 cells. Enzyme activity is stimulated 3- to 10-fold by treatment with the detergent Lubrol PX. However, enhancement of guanylate cyclase by fibroblast growth factor could not be demonstrated under a variety of assay conditions. In both NRK and BALB 3T3 cells guanylate cyclase activity is low during logarithmic growth and increases as the cells crowd together and growth slows. Guanylate cyclase activity is undetectable in homogenates of NRK cells transformed by the Kirsten sarcoma virus (KNRK cells) either in the presence or absence of Lubrol PX. Guanylate cyclase activity is also greatly decreased in NRK cells transformed by Moloney, Schmidt-Ruppin, or Harvey viruses. BALB 3T3 cells transformed by RNA viruses (Kirsten, Harvey, or Moloney), by a DNA virus (SV40), by methylcholanthrene, or spontaneously, all have diminished but readily detectable guanylate cyclase activity. Cyclic GMP phosphodiesterase activity is found predominately in the soluble fraction of NRK cells. This activity increases slightly as NRK cells enter the stationary growth phase. Cyclic GMP phosphodiesterase activity is undetectable in two clones of KNRK cells under a variety of assay conditions, and is decreased relative to the level present in NRK cells in a third KNRK clone. However, both Moloney- and Schmidt-Ruppin-transformed NRK cells have a phosphodiesterase activity similar to that found in NRK cells. Boiled supernatant from both NRK and KNRK cells is observed to appreciably enhance the activity of activator-deficient phosphodiesterase from bovine heart. This result indicates that the absence of cyclic GMP phosphodiesterase activity in KNRK cells is not due to a loss of the phosphodiesterase activator. The intracellular concentration of cyclic GMP is found to be very low in transformed NRK cells when compared to levels measured in confluent NRK cells. The low levels of cyclic GMP in transformed NRK cells reflect the greatly decreased guanylate cyclase activity observed in these cells. These results do not appear to support the suggestion that cyclic GMP promotes the growth of fibroblastic cells.