Randomized Comparison of Oral and Intravenous Fluid Regimens after Gallbladder Surgery

Numerous studies of post-operative fluid status have utilized sophisticated measurements of electrolyte distribution and fluid shift without relating results to clinical practice. The aim of this prospective randomized study was to investigate the response of patients undergoing abdominal surgery of moderate severity to conservative post-operative fluid administration. Forty-five patients undergoing open cholecystectomy were randomized to receive 2.51 of fluid (1 l normal saline and 1.51 5% dextrose), 1 l of normal saline, or free oral fluids (groups 1, 2, 3, respectively). Serum and urine osmolality and electrolytes were measured pre-operatively and at 24 and 48 h post-operatively. Patients remained in the study irrespective of the urine output. Plasma electrolytes and osmolality remained within normal limits in all three groups despite significant changes in urine electrolyte and osmolality in groups 2 and 3. This confirms that a conservative approach to fluid administration has no detrimental effect on hydration in fit patients with uncomplicated surgery.

Lectin-like binding ofBacillus thuringiensisvar,kurstakilepidopteran-specific toxin is an initial step in insecticidal action

The two delta-endotoxins comprising the Bacillus thuringiensis var. kurstaki HD1 insecticidal protein crystal were separated. The lepidopteran-specific protoxin was activated in vitro and its mechanism of action investigated. Toxicity towards Choristoneura fumiferana CF1 cells was specifically inhibited by preincubation of the toxin with N-acetylgalactosamine and N-acetylneuraminic acid. The lectins soybean agglutinin and wheat germ agglutinin, which bind N-acetylgalactosamine, also inhibited toxicity. Since N-acetylneuraminic acid is not known to occur in insects, these results suggest that the toxin may recognise a specific plasma membrane glycoconjugate receptor with a terminal N-acetylgalactosamine residue.

Structural insights into the mechanical regulation of molecular recognition sites

Intriguing experimental and computational data are emerging to suggest that mechanical forces regulate the functional states of some proteins by stretching them into nonequilibrium states. Using the extracellular matrix protein fibronectin as an example, we discuss molecular design principles that might control the exposure of a protein's recognition sites, and/or their relative distances, in a force-dependent manner. Fibronectin regulates many cellular functions by binding directly to integrins. Although integrins have a key role in the transduction of force across the cell membrane by coupling the extracellular matrix to the cytoskeleton, the studies reviewed here suggest that fibronectin might be one of the molecules responsible for the initial transformation of mechanical force into a biochemical signal.

In vitro responses of gallbladder muscle from patients with acalculous biliary pain

BACKGROUND

Diagnosis and identification of patients with acalculous biliary pain, who would benefit from surgery, remains a significant clinical problem. The cholecystokinin (CCK) provocation test helps diagnosis, but lack of consistency limits its usefulness.

AIM

To characterize the response of gallbladder muscle strips, from patients with acalculous biliary pain, to hormonal and muscarinic stimulation and to compare these with strips from gallstone patients and normal controls.

PATIENTS

Eleven patients with acalculous biliary pain were studied, 5 had a positive CCK test. Eight gallbladders from gallstone patients and 6 from partial hepatectomies were used for comparison.

METHODS

Muscle strips from the body and neck of the gallbladder were suspended in organ baths and dose-response curves were constructed for CCK-8 and carbachol.

RESULTS

In the acalculous group the strips from the body were less sensitive to carbachol than those of the neck.

CONCLUSION

Since we found no differences in the CCK responses for the groups, it casts doubt over the effectiveness of the CCK test to diagnose acalculous biliary pain. Since carbachol sensitivity was different, it might be that a similar test using muscarinic stimulation would help in the diagnosis of this difficult group of patients.

Cellular mechanisms of CNS pericytes

Three major functional roles have been ascribed to pericytes associated with central nervous system microvasculature-contractility, regulation o f endothelial cell activity, and macrophage activity. A host of different cell factors and signalling agents appear to be involved with these cellular functions, some effecting the pericyte and others produced by this cell. These include neuromodulators, vasoactive peptides, metabolic factors, growth factors and cytokines. The specific compounds and their actions are collectively viewed in an effort to provide an overall picture of the regulation of pericyte functional activity. This small vascular cell is emerging as a significant entity in several physiological processes through the functions of above; these processes include control of blood flow, regulation of vascular development and immune responses. Defining the regulatory agents and their mechanisms is key to understanding the role that pericytes play in these processes. Because these cells have begun to receive increasing attention in neurobiological studies, an overview of signalling properties should be timely and beneficial.

Cholecystectomy: does subspecialization alter workload?

AIMS: Cholecystectomy is a common operation. This study reviewed the changes in workload and practice in a teaching hospital over a 4-year period, during which a hepatobiliary subspecialist unit was developed. METHODS: Computerized demographic data, and details of operations and inpatient events were reviewed for all patients undergoing cholecystectomy in a single teaching hospital from 1993 to 1997. For statistical analysis the consultants were grouped into those with a hepatobiliary interest (n = 3) and those with other primary interests (n = 6); and the workload for the first 12 months of the study was compared with that of the last 12-month period. RESULTS: Between April 1993 and April 1997, 1121 cholecystectomies were performed, of which 75 were excluded because they were performed with other simultaneous procedures. Of the remaining operations, 911 involved cholecystectomy alone (mean patient age 52. 9 years), and 135 (12.9 per cent) comprised cholecystectomy with exploration of the common bile duct (ECBD) (mean age 60.1 years). Between the first and last years studied, the rate of ECBD rose significantly from 7.4 to 14.9 per cent (P < 0.01, chi2 test), and the proportion of ECBD procedures being performed by hepatobiliary specialists rose from 31.6 to 52.7 per cent, but this was not statistically significant (P = 0.13). However, for cholecystectomy in the same period the proportion performed by hepatobiliary surgeons rose from 40.4 to 58.5 per cent, representing a highly significant trend (P < 0.001). Following cholecystectomy alone there was a significantly shorter stay associated with patients treated by hepatobiliary surgeons (P = 0.002, F test), although the median postoperative hospital stay was 2 days for both groups of surgeons (interquartile range 1-3 days for hepatobiliary and 1-4 days for non-hepatobiliary surgeons). CONCLUSIONS: Although cholecystectomy is not viewed as a specialist procedure, the trend in this teaching hospital reveals a steady increase in the proportion of cholecystectomies being performed by teams with a biliary interest. The data indicate that this practice is associated with a shorter hospital stay.

Brain macrophages: on the role of pericytes and perivascular cells

Pericytes are a unique cell group intimately associated with the vasculature and that appear to be present in most tissues. Their presence is generally considered to be restricted to the microvessels - arterioles, venules and particularly capillaries, where there is little or no smooth muscle. Morphologically, the pericytes exhibit a small, oval cell body with multiple processes extending for some distance along the vessel axis; these primary processes then give rise to orthogonal secondary branches which encircle the vascular wall. Through this morphology and their close association with the vasculature, the contour of the cells conforms to that of the adjacent vascular element; also, they are usually enclosed within the basal lamina of the microvasculature. While many earlier studies suggested brain pericytes as a source of macrophage activity, recent results substantiate this functional role; these recent findings include the demonstration of macrophage markers, phagocytosis and antigen presentation. Coupled with current knowledge on the entry of lymphoblasts into brain tissue and perivascular areas as potentially being the primary site of cellular interactions for production of immune responses, this places the pericytes in a position to significantly contribute to central nervous system (CNS) immune mechanisms. They may in fact be the population of brain macrophages most instrumental in the initiation of an immune response. Although these cells constitutively express several macrophage properties, they are also capable of up-regulation to display the full range of macrophage functional activity. At least, some of the pericytic macrophages are located on the surface of the basal lamina as opposed to completely within it; however, their potential transformation into microglia of the parenchyma remains an open issue. In addition to their function as macrophages, pericytes appear to serve a host of other functional roles. They are contractile and seem to serve as a smooth muscle equivalent in the capillaries performing vasoconstriction; they regulate endothelial cell properties and contribute to the stability and maintenance of blood vessels; and they appear to directly participate in coagulation through the extrinsic pathway. Also, pericytes have been suggested to be pluripotential and serve as precursors for a variety of other cell types. From these functional roles, comes their involvement in various disease processes. In association with the macrophage function, they are involved in numerous autoimmune and infectious diseases. Through their vascular role, they are involved in diabetic retinopathy and inflammation. Also, the pericytes appear to have involvement in Alzheimer's as well as other diseases. Thus, these cells are presented not only as macrophages but as a group with broad functional activities and significant potential for contributing to disease states.

Mesenteric infarction due to combined protein C deficiency and prothrombin 20210 defects

The prothrombin gene mutation, 20210A, a guanine to adenine substitution at nucleotide position 20210, has recently been described as an additional risk factor for venous thromboembolic disease. We describe the case of a patient with combined heterozygous prothrombin 20210A mutation and type 1 protein C deficiency who presented with massive mesenteric venous infarction of his small bowel and survived following the use of protein C concentrate and extensive small bowel resection.

Affinity purification and catalytic properties of a soluble, Ca2+-independent, diacylglycerol kinase

We used a new procedure that involved selective enzyme binding to lipid vesicles to partially purify a soluble diacylglycerol kinase, then studied the relation between enzyme-vesicle binding and activity in vesicle-based assays. The vesicle-binding procedure required about 2 h, increased the enzyme's specific activity 50-fold with a 50% yield of activity, and combined well with additional purification steps. Studies of the activity of the partially purified diacylglycerol kinase toward vesicle-associated diacylglycerols revealed linear reaction kinetics that reflected enzyme binding to the vesicles; factors known to influence enzyme binding to the vesicles affected enzyme activity only indirectly, not by influencing the diacylglycerol kinase reaction itself. On the other hand, special incubation experiments that caused both substrate depletion in vesicles and enzyme stalling provided evidence that the diacylglycerol kinase could desorb from these vesicles, adsorb to freshly added, substrate-containing vesicles, and resume catalysis of phosphorylation reactions. The molecular basis for this enzyme-vesicle "hopping" behavior remains to be clarified. But enzyme-catalyzed conversion of diacylglycerol to phosphatidic acid may not have been a contributing factor because separate, enzyme-vesicle binding experiments showed that the enzyme had only a marginally higher affinity for diacylglycerol-containing vesicles than it did for vesicles that contained comparable amounts of phosphatidic acid. The combined results of our experiments suggest that the linear rates of diacylglycerol phosphorylation observed in standard assays with diacylglycerol-containing vesicles may have been combined functions of both the rate of enzyme hopping among vesicles and the rate of diacylglycerol phosphorylation by enzyme that was bound transiently on substrate-containing vesicles.

Multiple factors influence the binding of a soluble, Ca2+-independent, diacylglycerol kinase to unilamellar phosphoglyceride vesicles

We studied the influence of membrane lipids, MgCl2, and ATP on the ability of a soluble diacylglycerol kinase to bind to 100-nm lipid vesicles. The enzyme did not bind detectably to vesicles that contained phosphatidylcholine alone or to vesicles that contained 50 mol % phosphatidylcholine + 50 mol % phosphatidylethanolamine. But it did bind to vesicles that contained anionic phosphoglycerides, and maximal binding occurred (in the presence of MgCl2) when the vesicles contained anionic phosphoglycerides alone. When increasing amounts of phosphatidylcholine were included in phosphatidylserine-containing vesicles, enzyme binding to the vesicles decreased by as much as 1000-fold. However, when increasing amounts of phosphatidylethanolamine were included in phosphatidylserine-containing vesicles, little change in binding occurred until the concentration of phosphatidylserine was reduced to below 25 mol %. These results and results obtained with vesicles that contained various mixtures of anionic phosphoglycerides, phosphatidylcholine, phosphatidylethanolamine, and unesterified cholesterol provided evidence that anionic phosphoglycerides were positive effectors of binding, phosphatidylcholine was a negative effector, and phosphatidylethanolamine and unesterified cholesterol were essentially neutral diluents. Other experiments showed that diacylglycerol and some of its structural analogues also were important, positive effectors of enzyme binding and that addition of ATP to the medium increased their effects. The combined results of the study suggest that the enzyme may bind to vesicles via at least two types of binding sites: one type that requires anionic phospholipids and is enhanced by Mg2+ but inhibited by phosphatidylcholine, and one type that requires diacylglycerol and is enhanced by ATP.

Are complications of endoscopic sphincterotomy age related?

BACKGROUND

Endoscopic retrograde cholangiopancreatography sphincterotomy is increasingly performed in younger patients undergoing laparoscopic cholecystectomy. However, the safety of endoscopic sphincterotomy in this age group, relative to that in older patients, is unknown.

AIM

To determine whether the development of short term complications following endoscopic sphincterotomy is age related.

PATIENTS AND METHODS

A prospective multicentre audit of 958 patients (mean age 73, range 14-97, years) undergoing a total of 1000 endoscopic sphincterotomies.

RESULTS

Two deaths occurred, both from postsphincterotomy acute pancreatitis. Postprocedural complications developed in 24 patients: pancreatitis in 10, ascending cholangitis in seven, bleeding in four, and retroperitoneal perforation in three. There were six complications (five cases of pancreatitis and one bleed; 2.2%) and no deaths in the 281 (29.3%) patients aged under 65 years. In comparison, 18 (2.6%) of the 677 patients aged over 65 years developed a complication (cholangitis in seven, pancreatitis in five, bleeding in three, and perforation in three). Patients under 35, 45, 55, and 65 years were not at significantly increased risk of complication than those over these ages (relative risk for those under compared with those over 65 years 0.83, 95% confidence intervals 0.41-1.67, p = 0.74).

CONCLUSION

Short term complications following endoscopic sphincterotomy are not related to age. Younger patients undergoing laparoscopic cholecystectomy need not be denied endoscopic sphincterotomy for fear that the risks are greater than if they undergo surgical exploration of the common bile duct.

Extracorporeal shockwave lithotripsy for common bile duct stones

BACKGROUND

Successful extraction of common bile duct stones after endoscopic sphincterotomy may be achieved in 86-96 per cent of cases. However, some stones are too large to be removed in this manner. This study looks at the role of extracorporeal shock-wave lithotripsy to break up common bile duct stones as an adjunct to sphincterotomy in patients with stones greater than 10 mm in size.

METHODS

Twenty-seven patients with large (10-35 mm) common bile duct stones were treated with piezoelectric generated extracorporeal shock-wave lithotripsy (ESWL) following failed stone extraction after endoscopic sphincterotomy (ES). The stones were visualized ultrasonographically and a piezolith 2300 Wolf lithotripter used to administer the shockwaves.

RESULTS

Visualized stone fragmentation was reported in 20 of 48 sessions. Clearance of targeted stones was achieved in 18 of the 27 patients, but actual duct clearance was demonstrated in only 17 of the 27. There were few adverse effects and mortality was nil.

CONCLUSION

This study concludes that ESWL following failed ES is a useful additional treatment option for very large bile duct stones, but should only be used after surgical risk and past history of biliary disease have been carefully reviewed and found to contraindicate conventional surgical management. An algorithm of treatment options for common bile duct stones is presented.

A preliminary evaluation of an innovative synthetic soft tissue simulation module ('Skilltray') for use in basic surgical skills workshops

The results of a preliminary evaluation comparing the relative merits of biological (freshly-prepared animal offal tissue) and synthetic (Skilltray) simulation modalities are presented, subsequent to their use during two basic surgical skills courses organised by The Royal College of Surgeons of England and The Royal College of Physicians and Surgeons of Glasgow in September 1995, and at which 18 SHO grade surgical trainees attended. Each trainee completed a questionnaire at the end of the first session on the second day of the course to assist the evaluation. Our conclusions were as follows: 1. The synthetic tissues evaluated provided a useful and functionally reproducible means for learning the basic exercises included in the mandatory skills course. 2. Freshly-prepared animal tissues undoubtedly provided a more "realistic' medium for rehearsing the basic surgical techniques taught. Trainees preferred to use the synthetic tissues initially and then to progress to the fresh equivalents subsequently. 3. The Skilltray provided all the requisite elements for rehearsing basic tissue handling, suturing, and anastomotic techniques in a self-contained, easily transportable module. We would suggest that such a unit be given to each participant to take away at the end of the basic skills course, to enable consolidation of the skills learned. 4. Where the use of fresh tissues is not possible the highly functional nature of the synthetic simulators evaluated make it acceptable then to use them as the only training modality.

Longitudinal changes in bone mineral density and bone turnover in postmenopausal women with primary hyperparathyroidism

The aims of this study were to determine 1) whether primary hyperparathyroidism (PHPT) is associated with accelerated bone loss in postmenopausal women, 2) whether bone mineral density (BMD) and bone turnover change to a similar extent with surgery and hormone replacement therapy (HRT) in these patients, and 3) whether biochemical markers of bone turnover measured at baseline can be used to predict the change in BMD in these patients after different therapies. We studied 33 postmenopausal women with PHPT; their ages at the time of study ranged from 48-80 yr (mean +/- SD, 63 +/- 10). Total body (TB), lumbar spine (LS), and femoral neck (FN) BMD and biochemical markers of bone turnover were measured at baseline and 10-30 months (19 +/- 5) after parathyroid surgery, HRT, or no treatment. BMD was measured in 33 age-matched healthy controls at baseline and at a mean of 24 months. Baseline biochemical markers of bone turnover were measured in controls. In PHPT at baseline, the mean z-score of BMD was -1.25 at TB (95% confidence interval, -1.64 to -0.86), -0.95 at LS (-1.37 to -0.53), and -1.30 at FN (-1.65 to -0.95), whereas the mean z score was 0.45 for serum carboxy-terminal propeptide of human type I procollagen (0.02-0.89), 1.05 for bone alkaline phosphatase (0.38-1.71), 2.38 for 24-h urinary excretion of cross-linked N-terminal telopeptide of type I collagen (NTx; 1.63-3.13), and 2.36 for 24-h urinary excretion of galactosyl hydroxylysine (1.97-2.74). After surgery and HRT, BMD increased and bone turnover decreased during the follow-up. In the untreated group, BMD decreased at TB and FN, and levels of bone alkaline phosphatase, NTx/creatinine, and galactosyl hydroxylysine/creatinine increased. When the rate of change in BMD (percentage per yr) was compared with that in the control group, bone gain was significant at all three skeletal sites after surgery and HRT, and bone loss was significant at TB and FN, but not at LS, in the untreated group. There was a weak, but significant, correlation between baseline urinary NTx and the change in femoral neck BMD in the untreated group (r = -0.36; P = 0.05). We conclude that untreated postmenopausal women with PHPT have low BMD resulting from accelerated bone loss at the TB and FN. Surgery and HRT both restore BMD and bone turnover toward normal in postmenopausal women with PHPT. A single measurement of bone turnover is insufficient to predict BMD changes in individual patients with PHPT.

Local anaesthesia for major general surgical procedures. A review of 116 cases over 12 years

Between 1980 and 1992, 116 patients had either a simple mastectomy (32) or intra-abdominal procedures (84) under local anaesthesia (0.5-1% lignocaine with 1:200 000 adrenaline). A wide variety of general surgical procedures were feasible using only supplementary intravenous sedation (54%). Complications were uncommon and related to surgical procedure (three incorrect diagnoses, three procedures impossible) rather than the anaesthetic technique. There were no anaesthetic toxicity or postoperative problems. Local anaesthesia is extremely safe and facilitates larger surgical procedures than is generally appreciated.

Cavitation of mesenteric lymph nodes: a rare complication of coeliac disease, associated with a poor outcome

Five cases are presented, all of which showed peculiar cavitation of mesenteric lymph nodes. Clinically, three presented with abdominal symptoms, a mass or obstruction, warranting laparotomy. Two patients showed cavitating mesenteric lymph nodes at autopsy. Lymph nodes were enlarged with central, partly cystic degeneration; milky fluid exuded from the cut surface. In each case, investigation showed intestinal villous atrophy and splenic atrophy; coeliac disease was confirmed by response to gluten withdrawal. Three patients died, two from cachexia and the other from pneumonia; the other two are alive and well one year and six years after presentation. Review of the literature shows 12 previously reported cases, with a mortality of about 50%. The diagnosis is made by the histopathologist, alerting appropriate treatment. The pathogenesis is unknown.

Cellular forms and functions of brain microglia

Consistent with the recent characterization of microglial cells as macrophages, an overall picture for the unique function of these cells in CNS tissue has developed. The microglia are derived from blood monocytes that migrate into the tissue during fetal development and subsequently remain after complete formation of the blood-brain barrier. These monocytes give rise to the ramified microglia of adult tissue through the developmental intermediate of amoeboid microglia. Ramified microglia appear uniquely adapted in contrast to other tissue macrophages based on their stability or lack of turnover and mitotic capability. The ramified cells, while usually downregulated, can convert into active macrophages termed reactive microglia; this conversion appears to occur nonspecifically in response to any injury. Further, reactive microglial cells can fuse to form giant multinucleated cells during viral infections. Each microglia cell form possesses a characteristic morphology and differing functional state with regard to macrophage activity. In their role as tissue macrophages, microglia are involved in immune responses, tissue transplantation, and AIDS dementia complex, as well as many other neurological mechanisms and diseases.

Histochemical evidence for microglia-like macrophages in the rat trigeminal ganglion

Of the 4 major cell types in CNS parenchyma, microglia appear to serve the unique functional role of tissue macrophages. The distribution of equivalent cells in the PNS is unclear. Recently, the B4 isolectin of Griffonia simplicifolia was shown to bind selectively to microglia as well as to other macrophages under specific conditions. In the present study, this lectin was used to assess the existence of macrophages in the rat trigeminal ganglion. Vibratome sections of fixed ganglia were incubated with horseradish peroxidase (HRP)-conjugated isolectin, an HRP reaction subsequently performed, and sections processed for histology and viewed by light microscopy. Staining activity was found to be localised to a population of cells throughout the ganglion. These cells possessed small oval somata and several thin crenated processes, an appearance typical of ramified microglia. Stained cells also exhibited a regular, evenly spaced tissue distribution similar to CNS microglia. Finally, similar cells were also labelled by thiamine pyrophosphatase histochemistry, a cellular marker for CNS microglia/macrophages. It was concluded that there are microglia-like macrophages in the trigeminal ganglion and that these cells may function in immune reactions.

Identifying potential gun offenders

According to the results of a Saulwick Age Poll (The Age, 13 June 1988) one in three Australians aged 18 to 24 would like to have a gun. Many of them join pistol shooting clubs. Target pistol shooting, part of the Olympic Games programme, is a safe sport. It develops self discipline, teaches body control, to make decisions under pressure, how to handle stress and think logically as an individual. There are about 70 pistol clubs in Victoria. Following the rule "prevention is better than the cure" MISC introduced screening of new members. The system--interview, the questionnaire, a probation period--was found during the two year trial period successful as a strategy to identify people who are potential risks to society.

Who's afraid of informed consent?

OBJECTIVE

To test the assumption that patients will become unduly anxious if they are given detailed information about the risks of surgery in an attempt to obtain fully informed consent.

DESIGN

Preoperative anxiety assessed before and after patients were randomly allocated an information sheet containing either simple or detailed descriptions of possible postoperative complications.

SETTING

Four surgical wards at two Sheffield hospitals.

SUBJECTS

96 men undergoing elective inguinal hernia repair under general anaesthesia.

MAIN OUTCOME MEASURE

Change in anxiety level observed after receiving information about potential complications.

RESULTS

Detailed information did not increase patient anxiety (mean Spielberger score at baseline 33.7 (95% confidence interval 31.3 to 36.2), after information 34.8 (32.1 to 37.5); p = 0.20, paired t test). A simple explanation of the facts provided a statistically significant degree of reassurance (mean score at baseline 34.6 (31.5 to 37.6), after information 32.3 (29.8 to 34.9); p = 0.012), although this small effect is likely to be clinically important only in those whose baseline anxiety was high (r = 0.27, p = 0.05).

CONCLUSIONS

In men undergoing elective inguinal hernia repair a very detailed account of what might go wrong does not increase patient anxiety significantly and has the advantage of allowing patients a fully informed choice before they consent to surgery, thus reducing the potential for subsequent litigation.

Characterisation of ramified microglial cells: detailed morphology, morphological plasticity and proliferative capability

Several cellular properties of brain microglia in the rat were investigated using both whole tissue and cultures of dissociated cerebral cortical cells. As revealed by thiamine pyrophosphatase histochemistry, tissue microglia possessed a highly distinctive cellular morphology. Stained microglia showed similar overall features of morphology and distribution in both preparations; however, the cells in culture displayed some slight differences from those of the tissue, including larger somata and less developed processes. Through studying living ramified cells in culture, both morphological plasticity as evidenced by patterned variations in soma size and mitotic activity were directly confirmed. It was concluded that ramified microglia definitely possess proliferative capability, and this may reduce the need for blood cell recruitment in brain immune responses. In addition, cultured microglia exist in a somewhat more activated state than those in normal tissue, and in some instances undergo further activation as macrophages. This cortical tissue culture system should provide an amenable preparation for investigating the regulation of microglial function.

Brain macrophages: evaluation of microglia and their functions

There is now evidence approaching, if not having already surpassed, overwhelming in support of microglial cells as macrophages. Consistent with this cellular identity, they appear to arise from monocytes in developing brain where amoeboid microglia function in removing cell death-associated debris and in regulating gliogenesis. In normal adult tissue, ramified microglial cells with down-regulated macrophage functional properties may serve a constitutive role in cleansing the extracellular fluid. Under all conditions of brain injury, microglia appear to activate and convert into active macrophages. Activated and reactive microglia participate in inflammation, removal of cellular debris and wound-healing, the latter through regulation of gliosis in scar formation and a potential contribution to neural regeneration and neovascularization. In the activated state, microglia also express MHC's and, thus, may function in antigen presentation and lymphocyte activation for CNS immune responses. As uniquely adapted tissue resident macrophages within the CNS, microglia serve a variety of functional roles over the lifespan of this tissue. These cells may therefore be involved in or contribute to some disease states; such has been indicated in multiple sclerosis and AIDS dementia complex.

Partial splenectomy for massive splenomegaly secondary to Gaucher's disease

A 16 year old girl with Type 1 Gaucher's disease presented with massive splenomegaly, hypersplenism and abdominal discomfort. Traditionally hypersplenism has been treated with splenectomy, but this results in a high incidence of overwhelming sepsis and accelerated sphingolipid deposition in both liver and bone. A 90% partial splenectomy was therefore performed leaving a fully vascularized inferior segment of the spleen and resecting 5.8 kg of splenic tissue. The patient made an uneventful recovery with a marked improvement in her haematological parameters and general condition.

Loss of monomorphic and polymorphic HLA antigens in metastatic breast and colon carcinoma

MHC class I antigens are intimately involved in intercellular communication, and recognition by cytotoxic T cells. Thus tumour cells that fail to express them may be at a growth or metastatic advantage. A series of ten colorectal and ten breast carcinomas, and their respective lymph node metastases, were examined immunohistologically using monoclonal antibodies (mAb) against both monomorphic and A2 polymorphic determinants, and beta-2-microglobulin (beta 2m). Four colon polypoid adenomas stained positively throughout, but 6/10 primary tumours had partial or complete loss of expression of monomorphic determinants using mAb W6/32: two node and the liver metastasis showed less, four more expression. Similar results were seen for beta 2m. HLA-A2 expression was absent or reduced in 4/4 colon tumours and all their metastases. Among the breast tumours, W6/32 staining was absent or reduced in 2/10, and node deposits showed two with less reactivity than their primary. Beta 2m staining was reduced or absent in 8/10 primaries and all the node metastases; in every case in which beta 2m was detected in the primary tumour their corresponding lymph node metastasis showed a decreased expression. HLA-A2 expression was absent or reduced in 3/4 primary breast carcinomas, and all their metastases. These results show that individual human colon and breast carcinomas often have a reduced HLA class I antigen expression, which apparently confers a metastatic advantage.

Pinocytosis as a select marker of ramified microglia in vivo and in vitro

Based on previous observations in tissue culture, we investigated pinocytotic activity as a potential cell marker for brain microglia. This functional activity was assessed in three different preparations derived from rat: primary cultures of mixed cerebral cortical cells, tissue slabs of whole cerebrum, and cultures of isolated or enriched microglial cells. Each preparation was incubated with the fluorescent dye lucifer yellow as a soluble tracer and then processed for light microscopy. Under the conditions utilized, ramified microglia specifically exhibited differentially high pinocytotic labeling in all cases; the dye was mainly localized within the cell somata, where it was sequestered in pinocytotic vesicles. In each preparation, the identity of the labeled cell population was confirmed as microglia through immunohistochemical staining with the monoclonal antibody (MAb) OX-42, a specific microglial marker. Therefore, pinocytotic labeling is proposed as a select cell marker for microglia, which may be extremely useful in the identification and study of ramified microglial cells.

Evidence for motility and pinocytosis in ramified microglia in tissue culture

Ramified microglial cells were investigated in primary cultures of dissociated cerebral cortical tissue from rats. The identification of these cells was confirmed through immunohistochemical staining with 7 monoclonal antibodies selective for microglia. While there was significant variation in staining intensity with different antibodies, all stained the identified ramified cells; the antibodies OX-42 and ED1 yielded the most intense immunoreactivity. Based on distinctive morphological features, the microglia could be identified in living cultures where they were monitored using time-lapse video recording. This technique revealed extremely dynamic features of cellular plasticity and motility. Ramified microglia exhibited constant and rapid alterations in the size and shape of their cell body with an associated extension and retraction of processes; concomitantly, the cells moved about in a circumscribed area. These features of plasticity and motility were unique to this cell type, and correlated with OX-42 immunostaining. The microglia also possessed a differentially high level of pinocytotic activity; this too was correlated with OX-42 staining. From the nature of their morphological plasticity and motility, high pinocytosis, and cellular distribution, it is hypothesized that the ramified microglia specifically function as a system of fluid cleansing in normal brain tissue.

Characterization of ramified microglia in tissue culture: pinocytosis and motility

Functional properties of ramified microglia were investigated in primary cultures of rat cerebral cortical cells. These microglia could be readily identified in both fixed and living cultures through previously established features. Based on their destruction by 5 mM L-leucine methyl ester, a high level of intrinsic endocytotic activity was established. When cultures were incubated with fluorescent latex beads to assess phagocytosis, little or no such activity was exhibited by ramified cells. However, when cultures were incubated with dyes or other soluble tracer compounds, these cells always exhibited labeling. This labeling was selective for ramified microglia in the cultures and was demonstrated using a variety of compounds, including trypan blue, lucifer yellow, horseradish peroxidase (HRP), and India ink. Intracellular label could be observed in vesicular structures; this localization corresponded to an active cellular process. Also, cellular labeling was inhibited by the presence of colchicine. These features supported the inference that the labeling was attributable to pinocytosis, and this process appeared to account for the vast majority of endocytotic activity in the ramified microglia. Possible physiological significance of this pinocytotic activity was indicated by the accumulation of various neurotransmitters/modulators: gamma-aminobutyric acid and vasoactive intestinal polypeptide (VIP). Ramified cells in these cultures have been previously noted to exhibit a constant and rapid pattern of motility, which was consistently observed here through time-lapse video recording; pinocytosis and rapid motility were shown to concur in individual cells. Based on their high intrinsic pinocytotic activity and pattern of cellular motility, the ramified microglia specifically are suggested to serve a constitutive function of fluid cleansing within the interstitial spaces of brain tissue.

Pinocytotic activity in ramified microglia

Pinocytotic activity was investigated in rat cerebral cortex using the soluble tracers horseradish peroxidase and Lucifer yellow. A subpopulation of cells selectively accumulated both compounds and the labelling was mainly present in pinocytotic vesicles associated with the cell body. Labelled cell bodies were small, round to oval, and distributed in an almost regular array throughout the tissue. Based on distinctive morphological features, some of the labelled cells could be determined as ramified microglia. This identification was confirmed by immunofluorescence staining with the monoclonal antibody OX-42, which specifically recognizes microglia; OX-42 staining consistently co-localized with pinocytotic labelling. The possibility that ramified microglial cells perform a normal function of continuous fluid exchange in brain tissue is discussed.

Factors influencing the establishment of tumour-infiltrating lymphocyte cultures from human breast carcinoma and colon carcinoma tissue

Tumour-infiltrating lymphocytes (TIL) were obtained from breast and colon tumour tissue and cultured in vitro in the presence of recombinant human interleukin-2. Seven of 35 breast tumours and five of 41 colon TIL cultures were established in vitro: proliferation rates of greater than 10(3) were achieved. The cytotoxic capacity of these cells was determined against the cell lines K562 and SW742, and percentage cytotoxicity levels of greater than 97% and 79%, respectively, were seen. An inverse relationship between the ability of TIL to kill and their proliferative capacity was observed in all cultures. The prominent phenotype was CD3 positive, with greater than 55% of TIL expressing this antigen; there was no expression of CD16. The expression of CD56 and CD25 varied, being maximumly expressed on 64% and 38% of TIL, respectively. When greater than 90% of TIL expressed CD3, the ability of the culture to kill the target cell lines was low; only when there was an increase in the proportion of cells expressing CD56 and a decrease in the expression of CD3 was there high cytotoxicity. This study indicates that the TIL which proliferate in vitro in the presence of interleukin-2 are not necessarily the mediators of cytotoxicity.

Dynamic features of cells expressing macrophage properties in tissue cultures of dissociated cerebral cortex from the rat

Two previously identified forms of macrophage were investigated in primary cultures of cerebral cortical cells. Dynamic features were revealed through time-lapse video recording and aspects of macrophage function were assessed. The two cell forms were shown to be different pre-mitotic stages of a single cell type. The cell cycle for these cells involved an initial large, flat, quiescent cell which retracted to yield a slightly rounded form with numerous processes. This latter form lost processes and developed profuse filopodia as it became very rounded just prior to division; both resulting daughter cells then regained the initial large flat appearance. These cells possessed several properties of macrophages, including phagocytosis, nucleoside diphosphatase enzyme, and CR3 receptors. These properties were transient, expressed just before and after mitosis, but subsequently down-regulated in the flat daughter cells. Because of this feature, it was difficult to determine the exact size of this cell population; however, the observed rate of proliferation suggests it may be substantial. It is suggested that these cells correspond to non-microglial macrophages of brain tissue and, because of their significant down-regulation, they may be difficult to detect. This may be important in studies of brain accessory immune cells in tissue culture.

Squamous cell carcinoma of the stomach following gastric surgery

The development of adenocarcinoma in the gastric remnant following surgery for peptic ulceration is well recognised. However, squamous cell carcinoma of the stomach is rare, with only 80 cases being reported in the literature and none reported following gastric surgery. We report a case in which a squamous cell carcinoma with only minute areas of adenocarcinoma developed 22 years after surgery for a duodenal ulcer.

Characterization of the dynamic nature of microglial cells

Dynamic properties of ramified microglia were investigated in tissue cultures of rat brain cells. Microglia were identified in viable cultures based on previously determined aspects of their morphology and location, and this identification was confirmed through immunohistochemical staining for type-three complement receptors. When living microglial cells were monitored using time-lapse video recording, an extremely dynamic nature was revealed. These cells exhibited morphological alteration, surface and cytoplasmic activity, and migration. All of these properties were both constant and rapid, with individual cells being capable of assuming a completely different overall morphology within a period as short as 5-10 min. These dynamic properties were consistently observed in microglia and appeared specific to this cell type. Thus, ramified microglia appear to possess a unique and highly dynamic nature, and this feature is proposed as a potential marker for these cells. Additionally, the significance of microglial cellular dynamics in the functional role of this cell population in vivo is considered.

Morphological diversity of ependymal cells in tissue culture

Ependymal cells were visualized in primary cultures of cerebral cortex from rat using an immunohistochemical staining technique. Five different morphological subtypes of cuboidal ependyma were recognized: 1) round, 2) triangular, 3) columnar, 4) cone- and spindle-shaped, and 5) large pleomorphic cells. These cells varied in size and almost all possessed cilia. Two distinct forms of tanycyte ependyma were detected based on the presence of cilia. These features reflect a significant level of development of the ependymal cells in culture and may correspond to functional diversity within this group.

Method for the identification of brain macrophages/phagocytic cells in vitro

The use of labelled latex beads, with acute incubation conditions, for the identification of active macrophages in mixed cell cultures based on their phagocytic activity is described. Fluorescent beads provided the best results and selectively labelled active macrophage cells in cultures of blood monocytes. When this technique was applied to primary cultures of rat cerebral cortex, a specific cell type was significantly labelled. This was a small round cell, previously uncharacterized, which in addition to phagocytic activity indicated by the ingestion of beads also possessed macrophage biochemical markers. Thus, the procedure appears useful for phagocytic macrophage identification in vitro, and should be generally applicable to any tissue culture system. Additionally, this procedure can be rendered compatible with cell viability and, therefore, be utilized for long-term monitoring of macrophages.

Gastrointestinal malignancies as a complication of chronic myeloid leukaemia

A 70-year-old patient is presented who, after chemotherapy for chronic myeloid leukaemia, developed two separate gastrointestinal malignancies. His family history indicated a strong family tendency towards neoplasia, and it is speculated that this predisposition may have been potentiated by the chemotherapy or the leukaemic process itself. It is stressed that, in such cases of multiple malignancy, each condition should be treated on its own merits.

Further studies on the identification of microglia in mixed brain cell cultures

The investigation of brain microglia in primary cultures of dissociated cerebral cortical cells has been continued here utilizing a histochemical procedure for thiamine pyrophosphatase, which selectively stains microglia in whole tissue. This procedure also selectively stained a subpopulation of cells in the cortical cultures. The stained cells were small and exhibited quite variable morphology; from these features, a corresponding cell population could be identified in viable cultures. The stained cells, which were distinct from previously identified macrophage forms, were also distinguished from similar appearing cell types--small neurons and oligodendrocytes. Based on their staining properties, morphology, and distinction from other cell types, the identified cells are proposed as equivalents of ramified microglia.

Ontogeny of dopaminergic function in the rat midbrain tegmentum, corpus striatum and frontal cortex

Ontogenic development of the dopaminergic system in rat brain was investigated. This was accomplished by monitoring changes in postsynaptic dopamine receptor formation and presynaptic dopamine content in the midbrain tegmentum, frontal cortex and corpus striatum from the 18th day of gestation through adulthood. The dopamine antagonist spiperone was used as the binding ligand to quantitate receptor number while dopamine content was measured chromatographically. [3H]Spiperone binding kinetics in adult animals revealed that the maximum number of receptor sites (Bmax) was 160, 900 and 597 fmol/mg protein in midbrain tegmentum, frontal cortex and corpus striatum, respectively, while the corresponding equilibrium constant (Kd) values were 0.15, 0.52 and 0.15 nM. During the course of development, the affinity for spiperone binding in corpus striatum and frontal cortex did not change significantly, while in midbrain tegmentum the binding affinity in younger animals was significantly lower. Results from competitive inhibition experiments using various serotonergic and dopaminergic antagonists suggested that at all ages dopamine D2-receptors were responsible for spiperone binding in corpus striatum and midbrain tegmentum. In frontal cortex, binding properties consistent with D2-receptors were observed in non-adult animals; by the time adulthood was reached, however, spiperone binding characteristics were altered and appeared to correspond to serotonin sites. The developmental patterns of the dopaminergic markers were different in all 3 tissues. Adult receptor levels were achieved very early in midbrain tegmentum, while increases in receptor number continued in corpus striatum and frontal cortex, at different rates, throughout the postnatal period. A marked increase in dopamine in corpus striatum occurred during the second and third postnatal weeks and the transmitter content remained relatively constant after this time. Transient fluctuations in endogenous dopamine during the postnatal period were observed in midbrain tegmentum and frontal cortex. A general feature of the ontogenic pattern in all tissues appeared to be increases in dopamine receptor preceding increases in dopamine synthesis. A hypothesis on the developmental regulation of dopamine neurons was derived.

Acquired dysfibrinogenaemia masquerading as disseminated intravascular coagulation in acute pancreatitis

Acquired dysfibrinogenaemia as the cause of coagulation abnormalities occurred in a case of acute pancreatitis. Initial coagulation studies showed a prolonged thrombin time and increased concentrations of serum fibrinogen/fibrin degradation products and plasma D-dimer. Further studies on purified fibrinogen showed evidence of degradation of the C-terminal ends of the A-alpha chains, which, it is suggested, resulted from the action of circulating pancreatic proteases. Fibrin polymerisation was thus shown to be impaired, which explains the prolongation of the thrombin time. There was a temporal relation between increased amylase activities and the prolonged thrombin time, both of which returned to normal three weeks after admission. Acquired dysfibrinogenaemia may be an underrecognized phenomenon in acute pancreatitis and may lead to misinterpretation of coagulation test abnormalities.

Brain macrophages: questions of origin and interrelationship

Brain tissue appears to contain several distinct types of macrophages. An effort is made here to present a description of the complete cohort of macrophages and sources of phagocytic activity in this tissue. Initially, the criteria and methods used for the identification of tissue macrophages in general are considered. These include some morphological and ultrastructural features, assessment of phagocytic activity, and histochemistry for intracellular and surface components. Each of these methods or criteria has certain advantages but also associated problems and limitations; all have been applied in various instances to brain tissue. In a final analysis, the most reliable means of identification of tissue macrophages involves a combination of all of these approaches. The identification and characterization of macrophages have been rendered extremely confusing in the brain because of so many different sources of these cells, both intrinsic and blood-derived. The classes of macrophages or phagocytic cells in brain tissue are microglia, supraependymal cells, epiplexus cells, meningeal macrophages, pericytes, and direct blood-derived macrophages. The morphology, location, and functional properties of each of these classes is described. In an overall view, brain tissue is very well protected by intrinsic macrophages, and the locations and distribution of these cells are consistent with other tissues. Finally, in a consideration of origin and interrelationship, the idea is presented that the most likely source for all or most brain macrophages is monocytic blood cells. The latter cells appear to migrate into the tissue from several sites during embryogenesis and may continue to enter, at least from blood vessels, in the adult state.