Changes of trends in the size of the dental implants in recent years Part 1. The role of short implants in dental implantology The literature review

The requirements for osseointegration have been determined decades ago, among which was the appropriate size of the dental implants. In the last few years, in both - domestic and foreign literature- we can find more and more articles suggesting short and narrow dental implants as a treatment possibility. They may serve as an alternative to various bone grafting techniques and may replace the time demanding, more invasive and expensive horizontal and vertical bone augmentation procedures. Using short and narrow implants we can avoid interventions often accompanied by serious complications, such as bone distraction and inferior alveolar nerve transposition which pose greater risk for the patient. Our objective is a two-part review of the periodic literature in order to establish whether short and narrow dental implants can serve as a real alternative treatment modality.

Tissue-specific expression of the p53 tumor-suppressor gene in the intestine of transgenic mice exposed to DMH and p53 antibodies

We studied the tissue-specific expression of the p53 gene in different parts of the intestine of mice treated with low doses of a carcinogen and exposed to different p53 antibodies. The human p53 promoter-CAT transgenic mice were immunized with different p53 antibodies (monoclonal - PAb 421 and DO1, and polyclonal - H-p53 and anti-soluble p53 IgG) and then exposed to low doses of dimethylhydrazine (DMH). Enzymatic CAT activity was determined in the ileum and colon 8 weeks later after the final injection of DMH. Expression of the p53 transgene in the normal ileum was twice as high as in the colon. Treatment with DMH significantly decreased the expression of the p53 transgene both in the ileum (from 18% to 100%) and in the colon (from 10% to 52%). Vaccination of mice protected at least in part such a decrease. The most effective results were found after exposure of mice to polyclonal H-p53 and to a lesser extent to anti-p53 IgG. No difference was found in the effects of antibodies on the small and large intestines. We concluded that polyclonal antibodies were more effective than monoclonal ones in protection against anti-p53 action of DMH. The observation of these effects may make it possible to explain the higher antitumor activity of polyclonal antibodies.

A community hospital experience with colonoscopic polypectomies

This study analyzed 432 consecutive polypectomies performed in 279 patients in the gastroenterology unit of a community hospital. The patients were separated into 2 groups; group I--symptomatic patients considered suitable for colonoscopic examination, and group II--asymptomatic high-risk patients. The mean number of detected polyps was similar in both groups, the vast majority of the polyps in both groups were small (< 5 mm), and were mainly of tubular histology. Polyps in the rectosigmoid area were more common (56.6%) in the symptomatic patients than in the asymptomatic patients (44.1%). Fourteen percent of patients in group I and 33% in group II had no polyps within 60 cm from the anal verge. Carcinoma in situ was found in large polyps mainly in group I. Flat adenomas were not found in the studied population. The incidence of hyperplastic polyps was similar in both groups and did not predict the concomitant existence of adenomatous polyps. The male:female ratio was the same in both groups. The percent of detected polyps increased with age. A strong right shift in the location of the polyps was evident with increasing age. Multiple polyps were a common event in this Israeli population of symptomatic and high-risk asymptomatic patients. More than 30% of the polyps were found outside the reach of the sigmoidoscope, with this proportion increasing with age. These data provide further support to the claim that colonoscopy should therefore serve as the choice diagnostic tool in these high-risk populations.

Hyperinducible expression of the interferon-gamma (IFN-gamma) gene and its suppression in systemic lupus erythematosus (SLE)

Transient expression of IFN-gamma and IL-2 mRNA and its control by post-transcriptional and suppressive mechanisms were analysed in phytohaemagglutinin-induced peripheral blood mononuclear cells (PBMC) from 47 patients with SLE and 31 age-matched normal donors, using quantitative hybridization with antisense RNA probes. In SLE, basal levels of gene expression did not deviate from those of normal donors, but strongly aberrant patterns were obtained upon induction. The ratio of subjects exhibiting highly inducible IFN-gamma gene expression in their PBMC to those showing moderate or low inducibility was increased five-fold in SLE (P = 0.003). High inducibility was observed for 43% of SLE patients and was equally pronounced in partial remission, mild or active disease. Inducibility of IL-2 mRNA, by contrast, remained similar to that for normal donors. However, regulation of IFN-gamma gene expression differed for mild SLE. Patients with mild disease showing high inducibility of IFN-gamma mRNA in their PBMC not only had the highest frequency of responders, but also the highest extent of an individual response, defined by superinduction of mRNA, to agents that relieve suppression (gamma-irradiation) or post-transcriptional down-regulation (cycloheximide). By contrast, patients with active SLE showing high IFN-gamma mRNA inducibility had normal suppressive capacity as well as post-transcriptional control. Hence, both high inducibility of the IFN-gamma gene and its suppression are relevant to disease. Hyperactivation of the IFN-gamma gene may be alleviated in mild SLE by a vigorous, concomitant activation of post-transcriptional control and of cell-mediated suppression.

Short-term effect of erythropoietin on T-cell mitogenic proliferation in chronic renal failure patients

Uremic patients undergoing hemodialysis (HD) are known to be highly susceptible to infections. Recent data indicate that in addition to its well-known stimulating effects on red cell production, erythropoietin (EPO) may also have immunomodulating properties. The aim of this study was to examine the effect of EPO on lectin-induced T-lymphocyte transformation in uremic patients, as part of its effect on the immune response. Sixteen HD patients and 20 age- and sex-matched healthy controls were compared before and after 6 and 20 weeks of EPO treatment. T lymphocytes were analyzed for their mitogenic activity following treatment with phytohemagglutinin (PHA), concanavalin A (CON A) and anti-CD3 by measuring 3H-thymidine incorporation. HD patients showed reduced mitogenic responses to all mitogens tested, compared to healthy controls. During the 6 weeks of EPO administration, a significant increase in T-lymphocyte activity could be demonstrated following exposure to all three mitogens (PHA, from 32 +/- 2 to 45 +/- 8; CON A, from 11 +/- 3 to 25 +/- 9; anti-CD3, from 11 +/- 3 to 22 +/- 5, means +/- SD). This increase was augmented after 5 months of EPO treatment. We conclude therefore that EPO improves in vitro T-cell mitogenic proliferation, even after short periods of treatment.

A new dietary model to study colorectal carcinogenesis: experimental design, food preparation, and experimental findings

Experimental dietary studies of human colorectal carcinogenesis are usually based on the AIN-76A diet, which is dissimilar to human food in source, preparation, and content. The aims of this study were to examine the feasibility of preparing and feeding rats the diet of a specific human population at risk for colorectal neoplasia and to determine whether changes in the colonic morphology and metabolic contents would differ from those resulting from a standard rat diet. The mean daily food intake composition of a previously evaluated adenoma patient case-control study was used for the "human adenoma" (HA) experimental diet. Foods were prepared as for usual human consumption and processed by dehydration to the physical characteristics of an animal diet. Sixty-four female Sprague-Dawley rats were randomized and fed ad libitum the HA or the AIN-76A diet. Every eight weeks, eight rats from each group were sacrificed, and the colons and contents were examined. Analysis of the prepared food showed no significant deleterious changes; food intake and weight gain were similar in both groups. Compared with the controls, the colonic contents of rats fed the HA diet contained significantly less calcium, concentrations of neutral sterols, total lipids, and cholic and deoxycholic acids were increased, and there were no colonic histological changes other than significant epithelial hyperproliferation. This initial study demonstrated that the HA diet can be successfully processed for feeding to experimental animals and is acceptable and adequate for growth but induces significant metabolic and hyperproliferative changes in the rat colon. This dietary model may be useful for studies of human food, narrowing the gap between animal experimentation and human nutritional research.

The novel cyclic dinucleotide 3'-5' cyclic diguanylic acid binds to p21ras and enhances DNA synthesis but not cell replication in the Molt 4 cell line

1. The effect of the novel, naturally occurring nucleotide 3'-5' cyclic diguanylic acid (c-di-GMP) on the lymphoblastoid Molt 4 cell line was studied. When exposed to this guanine nucleotide. Molt 4 cells exhibited a marked increase in [3H]thymidine incorporation, up to 200-fold at 50 microM c-di-GMP. Correspondingly, the DNA content of the treated cells was 9-fold higher than untreated cells. Stimulation of [3H]thymidine incorporation into the cells was time- and concentration-dependent. This effect was specific and was not observed with GMP or cyclic GMP, nor with the unhydrolysable GTP analogues, guanosine 5'-[gamma-thio]triphosphate and guanosine 5'-[beta gamma-imido]-triphosphate. C-di-GMP entrance into the cells was experimentally verified and occurred without using any means of cell permeabilization. SDS/PAGE analysis of cells exposed to [32P]c-di-GMP, followed by autoradiography, revealed the labelling of three low-molecular-mass proteins at 18-27 kDa. The labelling is highly specific to c-di-GMP and its extent was not affected by other guanine nucleotides. 2. One of the c-di-GMP-binding proteins was found to be the p21ras protein, by immunoprecipitation with the anti-Ras monoclonal antibody Y13-259. The effects described appear to be unique for c-di-GMP and, taken together, raise the possibility that an irreversible binding of this guanine nucleotide to the growth-promoting p21ras protein results in a fixed active conformation of this protein affecting DNA synthesis. Strikingly, although at 48 h of growth markedly high DNA levels were found in Molt 4 cells treated with c-di-GMP, this guanine nucleotide had no effect on cell replication during this period. Thus Molt 4 cells exposed to c-di-GMP enter the S phase uncoordinated with their overall replication rate.

Immunohistochemical detection of p53 protein expression in HPV-induced condyloma acuminatum

Immunohistochemical peroxidase staining for p53 protein was performed on 22 condyloma acuminatum tissue samples from patients infected with human papillomavirus (HPV). The purpose of our study was to understand the benign character of this syndrome. The patients studied were infected by HPV type 6 and 11. Two monoclonal antibodies, PAbs DO-1 and 240, were used to detect the p53 protein. Overexpression of wild-type p53 was found in the nuclei of the basal cell layers. In healthy tissues and non-infected patients no p53 protein expression was detected. We would like to speculate that infection with HPVs and their viral protein E7, which is implicated in disruption of normal growth, may regulate the induction of wild-type p53 over-expression, as is known for DNA-damaging agents such as UV- or X-radiation.

Antioxidant enzymes activity in polymorphonuclear leukocytes in chronic renal failure

In the present study, activity of polymorphonuclear leukocyte (PMNL) intracellular antioxidant enzymes, i.e. catalase, superoxide dismutase (SOD) and glutathione peroxidase (GPX), was assessed in CRF patients on hemodialysis (HD), or continuous ambulatory peritoneal dialysis (CAPD) and in healthy controls. The activity of SOD and GPX was reduced in HD and in CAPD (SOD: by 34.2 and 42%, respectively, and GPX 66 vs. 42%, respectively, taking the activity in normal controls as 100%). Catalase activity, on the other hand, was significantly augmented (298 and 175%, respectively) as compared to the healthy controls. This impairment in antioxidant enzymes activity, involved in the respiratory burst and phagocytosis, may contribute to the understanding of the reduced bactericidal ability of PMNL activity found in these patients.

Parathyroid hormone and the cellular immune system

Parathyroid hormone (PTH) is the main hormone controlling calcium concentration in the extracellular fluid (ECF) through its biological activity on bone, kidney and intestine. However, data published over the last two decades indicate that PTH may act as an immunomodulator. The purpose of the present review is to summarize the effects of PTH on various immune functions. Polymorphonuclear leukocytes of patients with chronic renal failure (CRF) and elevated blood levels of PTH showed impaired migration, reduced phagocytic and bactericidal activity, and inhibited granulocyte chemotaxis. Antibody production and T and B lymphocyte proliferation are affected by PTH, both in vivo and in vitro. Possible implications of the involvement of PTH and its fragments in CRF are discussed.

Histochemical studies of progressive p53 mutations during colonic carcinogenesis in Sprague-Dawley rats induced by N-methyl-N-nitro-nitrosoguanidine or azoxymethane

We studied the increasing expression of the p53 tumor suppressor gene in Sprague-Dawley rats, chemically induced to develop colon cancer. p53 expression was evaluated histochemically at various stages of tumor progression (during a period of 40 weeks) that can be followed by colonic hyperproliferation labeled by 3H-thymidine incorporation. We found that high level nuclear expression of p53 protein correlates with progression of malignancy in carcinogen-induced animals, whereas cytoplasmic staining is related to the onset and early development of malignancy.

Red cell filterability in cigarette smokers and its relations to cardiac hypertrophy

The relationship among daily cigarette consumption, washed and non-washed RBC filterability time (FT) as an indicator of erythrocyte deformability and echocardiographic left ventricular mass (LVM) were examined in 25 clinically healthy smokers and in 25 non-smoking controls matched for sex and age. FT of non-washed RBC was significantly higher in smokers than in non-smokers (25.2 +/- 3.6 vs. 16.8 +/- 2.2 min, P < 0.001). A highly significant linear correlation between number of cigarette consumption and FT was found. These differences were not observed when RBC were washed three times with isotonic saline. LVM was significantly greater in smokers (85.5 +/- 13.4 g/m2) than in controls (61.8 +/- 6.7 g/m2, P < 0.001). A linear correlation between daily cigarette consumption and LVM was observed. A positive relationship between LVM and FT of non-washed RBC was also found. These results demonstrated that LVM is significantly elevated in smokers and is linearly correlated with both cigarette consumption and RBC filtratibility. The increased deformability found in smokers may be a determinant to the cardiac hypertrophy. The association of both elevated LVM and rheological impairment may indicate unfavourable prognosis.

Effect of oxygen tension on activity of antioxidant enzymes and on renal function of the postischemic reperfused rat kidney

The aim of the present study was to examine the effect of exposing animals to 100% oxygen instead of room air on renal function and endogenous antioxidant enzymes of the postischemic reperfused rat kidney. Superoxide dismutase (SOD), catalase and glutathione peroxidase (GPX) were determined in the homogenate of the left kidney after 45 min of ischemia, caused by clamping the left renal artery, 10 and 90 min after reperfusion while the animals breathed room air or 100% O2. The right kidney served as a control. The possible influence of trapped blood in the clamped kidney was also investigated by the use of a correction factor based on the Hb concentration in the homogenate. The results indicate that such correction is necessary as the blood adds significant antioxidant activity. The activities of all 3 enzymes after 45 min of ischemia decreased significantly in the left (ischemic) compared to the right (control) kidney, to 64% of the control levels for catalase, 58% for SOD and 49% for GPX. After 10 min of reflow, a further decrease in the activities of catalase (to 49%) and of GPX (to 29%) was found. SOD activity, however, increased to 64%. After 90 min of reperfusion, restoration toward normal levels was noticed (SOD activity increased to 70%, catalase to 76% and GPX to 58%). Breathing 100% O2 resulted in a significant decrease in all enzyme activities (to 38.6% for catalase, 45% for SOD and to 27.4% for GPX). This inactivation can be explained by increased reactive oxygen species (ROS) activity during hyperoxia.(ABSTRACT TRUNCATED AT 250 WORDS)

Regulation of interleukin-2 and interferon-gamma gene expression in renal failure

Regulated expression of interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) genes, induced in cultured peripheral blood mononuclear cells from patients with end-stage renal disease on hemodialysis (HD; N = 13) or peritoneal dialysis (PD; N = 13), was compared to that of 32 normal donors. Culture conditions were chosen that measure the transient, phytohemagglutinin-induced expression of IL-2 and IFN-gamma messenger RNA (mRNA), as well the intactness of post-transcriptional and suppressor T cell-dependent mechanisms that control this expression. The latter was achieved by analyzing the superinduction of IL-2 and IFN-gamma mRNA occurring upon culture with cycloheximide or after low-dose gamma-irradiation, respectively. HD subjects showed a complete loss of inducibility of the IL-2 gene, concomitant with decreased inducibility of IFN-gamma mRNA. In PD subjects, by contrast, expression of IL-2 mRNA was as vigorous as in normal donors, while IFN-gamma mRNA was even more strongly inducible. This difference in gene inducibility is caused by a lack of T cell function in HD subjects. The defect in IL-2 gene expression in HD subjects, occurring most likely at transcription, may underly their impaired immune function.

Effect of converting enzyme inhibitor captopril on T cell functions in essential hypertension

T cell function tests were performed in 6 patients with uncomplicated essential hypertension (EH) before and after treatment with captopril, an angiotensin-converting enzyme inhibitor. Total T and T cell subsets were within normal range and were not affected by the drug. The response of PBL to lectin stimulation was significantly impaired. While the stimulation index (SI) was almost normal when washed PBL were used (32.2 +/- 6.90 with PHA and 20.17 +/- 4.1 with Con A) or after their incubation with serum taken from normal subjects (40.42 +/- 10.9 and 15.53 +/- 3.4, respectively), autologous serum significantly reduced the SI (15.04 +/- 5.9 with PHA, p less than 0.05 and 6.68 +/- 1.45 with Con A, p less than 0.005). While captopril seemed to suppress the SI of washed PBL after 1 week of treatment, it enhanced the SI from 32.21 +/- 6.91 to 55.32 +/- 10.76 for PHA and from 20.17 +/- 4.13 to 30.63 +/- 5.41 for Con A (p less than 0.001). This effect was more obvious when the stimulations were performed with normal serum (from 40.42 +/- 10.9 to 96.47 +/- 17.51 for PTH and from 15.53 +/- 3.43 to 40.02 +/- 8.0 for Con A, (p less than 0.001). These results confirm previous reports indicating that the cellular immune response is impaired in EH. It seems that an inhibitory factor found in the serum of these patients is responsible for this impairment. Our findings may suggest that this factor may be angiotensin II.

Proliferative response of T lymphocytes to mitogenic lectins in essential hypertension

Several studies in human and experimental models indicate the existence of a partial relationship between essential hypertension (EH) and the immune system. In this study, cellular immune functions were investigated in 13 patients with untreated and uncomplicated essential hypertension (EHP) and in 10 of their offspring (EHO) and compared to 13 age- and sex-matched normotensive controls (NC) and 10 of their offspring (NCO). The total number of T cells and T cell subsets were similar in all groups examined. In the EHP, basal lymphocyte transformation without lectins was significantly lower (1,126 +/- 261 cpm of [3H]-thymidine uptake) than in the NC (3,223 +/- 736, p less than 0.01); the response to both phytohemagglutinin (PHA) and concanavalin A (ConA) revealed reduced [3H]-thymidine uptake as compared with NC (21,890 +/- 5,432 compared to 64,574 +/- 9,723 for PHA and 10,488 +/- 2,621 compared to 37,334 +/- 8,148 for ConA, respectively, p less than 0.01). However, the ability to proliferate as a response to lectins was normal. This was leading to a normal stimulation index in both groups. In the EHO, non-significant decrease in basal transformation and reduced uptake with PHA (49,537 +/- 7,478) versus NCO (69,911 +/- 7,254) and NC (64,574 +/- 9,723) were found. These findings suggest that the proliferative response of T lymphocytes is partially suppressed in EH.

Effect of a calcium-enriched diet on the colonic epithelial hyperproliferation induced by N-methyl-N'-nitro-N-nitrosoguanidine in rats on a low calcium and fat diet

We examined whether hyperproliferation of colonic crypt epithelium during cancer induction by N-methyl-N-nitro-N-nitrosoguanidine (MNNG), in rats on a low fat and calcium diet could be reduced by added calcium p.o. From the age of 4 weeks, 104 male Sprague-Dawley rats received a low fat (3.5%), low calcium (0.05% calcium ion), and low vitamin D (0.4 IU/g) diet. Sixty-four also had calcium salts, derived from either calcium lactate or solubilized calcium carbonate, added to their drinking water; therefore their total calcium intake was about 1% of daily diet. At age 12 weeks the rats were divided into 4 treatment groups: 8 rats, not receiving added calcium, had rectal saline instillations weekly (saline control group) and were sacrificed after a further 28 weeks; 3 groups of 32 rats each received intrarectal MNNG (1.5 mg) weekly. One group, not receiving added calcium, was the MNNG control group; while the second group also received added calcium lactate, and the third group received calcium carbonate. Groups of 24 were sacrificed periodically until 28 weeks of treatment. Rats were sacrificed and epithelial proliferation was estimated, 1 week after the last intrarectal instillation, by in vivo labeling with tritiated thymidine and measuring the ratio of labeled to total colonic crypt epithelial cells. The mean labeling index of the MNNG treated and added calcium groups were significantly higher (8.7-9.5%) than that of the saline controls (2.8%) only at week 28; however, it was then still significantly less than that of the MNNG controls not having added calcium (17.9%). Hyperproliferation, during induction of colonic cancer by MNNG in rats on a low calcium diet, can be reduced by a calcium enriched diet even in the presence of a low fat intake.

Effect of parathyroidectomy on T cell functions in patients with primary hyperparathyroidism

The notion that parathyroid hormone (PTH) can serve as an immunomodulator was examined. T cell function tests were performed in 3 patients with primary hyperparathyroidism before and 1 month after parathyroidectomy (PTX). Three normal volunteers, age and sex matched, were used as controls. One patient with lipoma of the neck was also examined before and after surgical removal of the lesion. In the primary hyperparathyroidism patients the total T cells were lower, the suppressors were higher and the helper to suppressor ratio was significantly lower than in control subjects. The lectin-stimulated lymphocyte transformation was significantly inhibited. All these abnormalities were restored to normal after PTX. Depressed lymphocyte activity was found also in the patient with lipoma. However, no change occurred after surgery. These results support the assumption that excess blood levels of PTH may have an immunosuppressive effect.

Methyldopa-induced syndrome of inappropriate antidiuretic hormone secretion and bone marrow granulomatosis

A case of an elderly man who developed severe hyponatremia and bone marrow granulomatosis while taking methyldopa is described. The hyponatremia was found to be due to the syndrome of inappropriate antidiuretic hormone secretion (SIADH). Bone marrow biopsy revealed granulomas. A MEDLINE search of the English literature was done, yielding only one previous report of methyldopa-induced bone marrow granulomatosis and no previous reports of methyldopa-induced SIADH.

Colon cancer bearing rats produce a lymphokine which induces macrophage migration inhibition (MIF) in vitro

We studied a series of 40 rats at various stages of colorectal carcinoma, as induced by N-methyl-N-nitro-Nitrosoguanidine. Lymphokine containing supernatants were obtained simultaneously from splenic and peripheral lymphocytes, after exposure to rat colon cancer antigen in vitro. The lymphokine was found capable of performing Macrophage Migration Inhibition (MIF) when obtained from rats with: carcinoma through serosa, carcinoma of submucosa, carcinoma of the mucosa and carcinoma in situ. All control rats were free of cancer and were MIF negative. The MIF response in this study was evaluated as a marker of chemically induced colorectal carcinoma in rats in order to better understand the lymphocyte response to tumor progression from atypia to adenocarcinoma of the colon.

In vitro effect of PTH on normal T cell functions

Uremia is associated with impairment of various cell-mediated immunity functions. The effect of parathyroid hormone (PTH) - known to be elevated in uremia - on several T cell functions has been studied. Normal peripheral blood lymphocytes incubated with increasing amounts of human PTH (HPTH) or bovine PTH (BPTH) showed a considerable decrease (up to 40%) in lectin-induced lymphocytes transformation, significant decrease in helpers to suppressors ratio, and marked inhibition of E rosette formation and T11-positive cells. PTH alone showed no cytotoxic effect on lymphocytes when incubated with or without mitogens. Glucagon, in concentrations up to 10-fold those found on uremia, had no effect on T cell function. Thus the effect of PTH was specific to the hormone action. The direct effect of PTH on normal T lymphocytes and some of their immunological responses is not clear. However, the results of this study support the hypothesis that excess blood levels of PTH may play a role in the pathogenesis of the impairment of the immune response in uremia.

Comparison of two lymphokines (macrophage migration inhibition, leukocyte adherence inhibition factors) and carcinoembryonic antigen, in colorectal cancer and colonic premalignant lesions

Previous studies in our laboratory on 92 patients with colonic cancer have suggested a promising degree of specificity and sensitivity for a macrophage migration inhibition factor (MIF) test using patient's lymphocytes incubated with a human colon cancer extract. This study compares the results of the MIF technique with serum carcinoembryonic antigen (CEA) levels and with the lymphocyte adherence inhibition (LAI) test in 18 colon cancer patients and 27 patients with conditions considered to predispose to colon cancer (colonic adenomas, ulcerative colitis, and Crohn's disease). Among colonic cancer patients, MIF and LAI were positive in 17 out of 18, but CEA was elevated in eight. MIF and CEA were negative in all 16 normal control subjects; LAI was negative in 13. Among patients with colonic adenomas, MIF and LAI were positive in three of five; CEA was negative in all. In the ulcerative colitis and Crohn's disease group, MIF was positive in seven of 22, LAI was positive in 11, and CEA was negative in all 22. Thus, MIF and LAI appear to be sensitive marker's for human colonic cancer. More extensive studies and precise characterization of these groups are warranted.

The macrophage migration inhibition (MIF) assay as a marker of colorectal cancer. Studies in patients with colorectal cancer, noncolonic neoplasms, and conditions predisposing to colorectal cancer

A specific macrophage migration inhibition assay, using patient lymphocytes incubated with a human colonic cancer extract, was studied in 92 patients with proven colorectal cancer and in 134 other individuals (20 normal controls, 80 patients with various nonmalignant gastrointestinal diseases, and 34 patients with extracolonic malignancies). A positive response was obtained in 78 of 92 colorectal cancer patients, but in none of the 20 normal controls. A positive response occurred in four of 34 patients with extracolonic malignancies and in approximately half of patients with colonic adenomas and in one third of patients with ulcerative colitis. The significance of positive results in these patients (with diseases considered premalignant) is unclear, and is being studied further. In patients with previous resection of colorectal cancers, positive responses were frequent during the first year following resection, and rare thereafter. The results suggest that this method may be useful as a clinical marker for colorectal cancer, and warrants further technical refinement and study of specific patient populations.

Acute undifferentiated leukemia: induction of partial differentiation by phorbol ester

Expression of lineage-associated surface antigens, was studied in 7 patients with acute undifferentiated leukemia (AUL), 3 patients with acute myeloid leukemia (AML), 4 patients with acute lymphoid leukemia (ALL) and bone marrow from 2 healthy donors, before and after exposure to the differentiating agent 12-O-tetradecanoylphorbol-13-acetate (TPA). The surface antigens were identified by monoclonal antibodies (My4, My8, My9, MO1, B1, CALLA, T11) and formation of EA and EAC rosettes. Adherence to plastic was also assessed. Cells from the AML patients responded to TPA with an increase in myeloid antigen positive cells and other markers of differentiation. Four of the AUL patients showed, also, a large increase in the fraction of cells expressing one or more myeloid markers, in correlation with formation of EAC rosettes. In contrast, the percentage of cells expressing myeloid antigens, did not increase in the 4 ALL patients, or in the normal donors. These findings confirm the heterogeneity of undifferentiated leukemias, and suggest the hypothesis that some AUL's can be induced to express markers of early myeloid cells.

Temperature regulation and water metabolism in the elephant shrew Elephantulus edwardi

1. The Cape elephant shrew Elephantulus edwardi maintained a stable body temperature (37.6 C) over a wide range of ambient temperatures. 2. Normal eutherian mechanisms of temperature regulation were employed in the maintenance of homeothermy. 3. Water turnover rate and metabolic rate were lower than predicted for a similar-sized eutherian. 4. Maximal urine concentration was fairly high (3118 +/- 267 mOsm/kg) with urine osmolality largely dependent on the urea concentration. 5. Relative medullary thickness of the kidney (6.61 +/- 0.84) indicated a higher maximum urine concentration than found in the laboratory and reflected an arid habitat. 6. E. edwardi can be classed among the "advanced" homeotherms in view of the physiological adaptations employed for survival.

Effect of polar organic compounds on leukemic cells. Butyrate-induced partial remission of acute myelogenous leukemia in a child

Polar organic compounds, such as dimethylsulfoxide and butyric acid, are known to induce differentiation in Friend erythroleukemia cells as well as in other cell types. It has been found that many of the compounds that induce cellular differentiation, inhibit 3H-thymidine incorporation and induce cell damage when incubated with leukemic cells from patients with acute or chronic myelogenous or acute lymphocytic leukemia. These effects are time and dose dependent. Among the compounds tested, butyrate was the most potent. Parenteral administration of butyrate (500 mg/kg/day) for ten days to a child with acute myelogenous leukemia in relapse, and resistant to conventional therapy, resulted in elimination of myeloblasts from the peripheral blood, an increase in mature myeloid cells and a reduction in 3H-thymidine uptake by the patient's peripheral blood cells. Bone marrow myeloblasts were reduced from 70-80% to 20% following the course of intravenous butyrate. No impairment of liver or renal function and no coagulation abnormalities were observed during butyrate treatment. Organic agents that induce cell differentiation may provide additional reagents for the clinical management of selected cases of leukemia.

Desensitization of enucleated cells to hormones and role of cytoskeleton in control of normal hormonal response

Prostaglandin E1 and the beta-adrenergic hormone l-isoproterenol stimulated cyclic AMP formation in both nucleated and enucleated myeloid leukemic cells that could be induced to differentiate normally to mature cells by the macrophage- and granulocyte-inducing protein MGI (MGI+D+ cells). Enucleated as well as nucleated MGI+D+ cells also desensitized to these hormones, indicating that this desensitization is an extranuclear process. Nucleated or enucleated mutant myeloid leukemic cells that are not induced to differentiate (MGI-D- cells) were not desensitized to these hormones. The antitubulin alkaloids colchicine and vinblastine, but not the antimicrofilament compound cytochalasin B, increased the maximal hormone-induced formation of cyclic AMP in nucleated MGI+D+ cells but not in the MGI-D- cells. These alkaloids also inhibited the development of desensitization to l-isoproterenol and prostaglandin E1 in enucleated MGI+D+ cells. The results indicate that in MGI+D+ cells the cytoskeletal system puts constraints on the cells' ability to respond to these hormones and that these constraints are absent in the mutant MGI-D- cells. Because MGI+D+ but not MGI-D- cells can be induced to differentiate by the macrophage- and granulocyte-inducing protein, cytoskeletal constraints, which are also found in normal myeloid cells, may be necessary for cell competence to differentiate. The results support the suggestion that membrane cytoskeletal constraints generate may control the normal response and desensitization to membrane-mediated cell inducers.