Fas and Fas ligand interactions suppress melanoma lung metastasis.

Apoptosis induced by Fas (CD95) ligation is frequently lost during tumor progression; however, there is no direct evidence to support an association of Fas loss-of-function with metastatic tumor behavior. To determine whether Fas loss-of-function is critical for acquisition of the metastatic phenotype, we have compared the ability of Fas-sensitive K1735 murine melanomas to form spontaneous lung metastases in wild-type and Fas ligand-deficient mice. Fas-sensitive melanoma clones are highly tumorigenic but rarely metastatic in wild-type syngeneic mice. However, in Fas ligand-deficient mice, both the incidence and number of metastases are increased. These findings provide the first evidence that Fas-Fas ligand interactions can suppress metastasis and that tumor Fas loss-of-function may be causally linked to metastatic progression.

A critical role for Fas ligand in the active suppression of systemic immune responses by ultraviolet radiation.

Induction of antigen-specific suppression elicited by environmental insults, such as ultraviolet (UV)-B radiation in sunlight, can inhibit an effective immune response in vivo and may contribute to the outgrowth of UV-induced skin cancer. Although UV-induced DNA damage is known to be an initiating event in the immune suppression of most antigen responses, the underlying mechanism(s) of such suppression remain undefined. In this report, we document that Fas ligand (FasL) is critical for UV-induced systemic immune suppression. Normal mice acutely exposed to UV exhibit a profound suppression of both contact hypersensitivity and delayed type hypersensitivity (DTH) reactions and the development of transferable antigen-specific suppressor cells. FasL-deficient mice exposed to UV lack both transferable suppressor cell activity and primary suppression to all antigens tested, with the exception of the DTH response to allogeneic spleen cells. Interestingly, suppression of this response is also known to occur independently of UV-induced DNA damage. Delivery of alloantigen as protein, rather than intact cells, restored the requirement for FasL in UV-induced immune suppression of this response. These results substantiate that FasL/Fas interactions are essential for systemic UV-induced suppression of immune responses that involve host antigen presentation and suggest an interrelationship between UV-induced DNA damage and FasL in this phenomenon. Collectively, our results suggest a model whereby UV-induced DNA damage disarms the immune system in a manner similar to that observed in immunologically privileged sites.

Fas ligand: a sensor for DNA damage critical in skin cancer etiology.

DNA-damaged cells can either repair the DNA or be eliminated through a homeostatic control mechanism termed "cellular proofreading." Elimination of DNA-damaged cells after ultraviolet radiation (UVR) through sunburn cell (apoptotic keratinocyte) formation is thought to be pivotal for the removal of precancerous skin cells. Sunburn cell formation was found to be dependent on Fas ligand (FasL), a pro-apoptotic protein induced by DNA damage. Chronic exposure to UVR caused 14 of 20 (70 percent) FasL-deficient mice and 1 of 20 (5 percent) wild-type mice to accumulate p53 mutations in the epidermis. Thus, FasL-mediated apoptosis is important for skin homeostasis, suggesting that the dysregulation of Fas-FasL interactions may be central to the development of skin cancer.

Antiglobulins and glomerulonephritis. Classification of patients by the reactivity of their sera and renal tissue with aggregated and native human IgG.

Renal biopsies and sera from 41 consecutive patients were studied to determine if antiglobulins were found more frequently in patients with severely diseased glomeruli. Patients were classified into three groups: A, 12 patients with normal renal function and minimal histological evidence of glomerular disease; B, 18 patients with normal renal function but distinctly abnormal biopsies (16 cases) or proteinuria greater than 16 g/24 h (2 cases); and C, 11 patients with both decreased function and abnormal histology. Positive latex fixation tests for rheumatoid factor were found in none of group A, four (22%) of group B, and five (45%) of group C patients. Sera heated 56 degrees C for 30 min contained precipitins reactive with heat-aggregated IgG in none of seven group A, five of ten (50%) group B, and four of ten (40%) group C patients. The quantity of 135I-labeled patient globulin which bound to immunoadsorbents coated with Cohn fraction II in competition with an equal quantity of 131I-labeled globulin from pooled plasma of normal donors was also measured. Patient globulins bound in significantly greater quantity (greater than or equal 2 SD) than the control in none of the group A, 7 of 18 (39%) group B, and 7 of 11 (64%) group C patients. Renal biopsies from 18 patients were also studied for the ability to fix fluorescein-conjugated heat-aggregated and native human IgG. None of nine tissue specimens from group A or B patients fixed either fluorescein-conjugated protein whereas tissue from eight of nine group C patients showed glomerular localization of one or both reagents. Severity of disease as judged by renal function and glomerular histology correlated with the presence of tissue-fixed and serum antiglobulins. Thus, detection of antiglobulins in glomeruli and sera of patients with glomerulonephritis may indicate a relatively poor prognosis and raises the possibility that antiglobulins may be implicated in some way in the pathophysiology of human glomerulonephritis.

Effect of human natural killer cells on the metastatic growth of human melanoma xenografts in mice with severe combined immunodeficiency.

An in vivo model for human melanoma was established with the growth of CR3 and DE5 human melanoma tumor cells following i.v. injection into C.B.-17 severe combined immunodeficient mice depleted of murine natural killer (NK) cells. The ability of human NK cells to mediate antitumor activity in vivo was investigated by evaluating the number of lung nodules and survival of mice given injections of human NK cells i.v. early after injection of CR3 tumor cells. Under these conditions, human NK cells effectively reduced lung nodule counts and prolonged survival when coinjected with interleukin 2 (IL-2). Multiple injections of IL-2 given during the first 16 h post-NK injection did not further enhance the tumor reduction. Significantly increased antitumor activity against CR3 tumor cells in vivo was observed in mice receiving NK cells coinjected with IL-2 and interleukin 12 (IL-12) in comparison to NK cells and IL-2 only. However, coinjection of IL-12 with human NK cells alone did not reduce the tumor burden. These results demonstrate the antitumor activity of human NK cells against human melanoma in severe combined immunodeficient mice and its augmentation by IL-2, alone or in combination with IL-12, suggesting that this model can be used to further investigate the interaction between human NK cells and human tumors.

Growth and metastasis of fresh human melanoma tissue in mice with severe combined immunodeficiency.

Cryopreserved cell suspensions of freshly excised melanoma metastases from nine patients were injected s.c. into C.B-17 severe combined immunodeficiency (SCID) mice. All 9 tumors grew as s.c. masses and six of nine were successfully transplanted into other SCID mice. Transplant inocula as low as 5 x 10(5) cells resulted in 100% tumor incidence. Moreover, seven of nine tumors metastasized, five from the original s.c. implants and two from transplanted s.c. tumors. Metastases were detected mainly in the lungs but also were found in abdominal viscera (liver, spleen, and pancreas) and thoracic lymph nodes. Flow cytometric analysis showed that expression of a panel of melanoma antigens, melanoma-associated proteoglycan, ganglioside GD3, and ganglioside GD2, was maintained with SCID passage. The original tumor inocula contained a variable percentage of tumor-associated lymphocytes (1-76%). Flow cytometry analysis indicated that these were mainly CD3+ T-cells. However, there was no correlation between the percentage of tumor-associated lymphocytes and the time required for development of a palpable tumor after s.c. injection or the ability to metastasize. These results demonstrate the growth and spontaneous metastasis of fresh human melanoma in SCID mice and suggest that this model could be important for therapeutic and basic biological studies.

The effect of age on the character of immune complex disease: a comparison of the incidence and relative size of materials reactive with Clq in sera of patients with glomerulonephritis and cancer.

The impact of aging on the severity of chronic immune-complex glomerulonephritis was studied in 144 patients from whom diagnostic renal biopsies were obtained over a 3-year period. Glomerulonephritis was related to an antecedent streptococcal infection in nine of these patients. In 58, glomerulonephritis occurred in association with a systemic disease; 27 of these had lupus erythematosus. At the time of the renal biopsy, serum creatinines were more frequently abnormal in men over 40 years of age. Similarly, histological evidence of irreversible glomerular injury was more evident in men over 40. Histological indices of renal glomerular injury correlated with the presence of intense fluorescent antibody reactions specific for C3 and C4 and IgG in the glomeruli. High serum Clq binding activities (Clq BA), an indication of the presence of circulating immune complexes, also were found significantly more often in males over 40. High serum Clq BA correlated with renal functional and biopsy evidence of severe glomerulonephritis. The renal biopsies in 89 cases were tested with fluorescein-conjugated heat-aggregated IgG (FAIgG) to determine how many contained focal immunoglobulin deposits with antiglobulin activity. Antiglobulins were detected in glomeruli of 24 patients and were found significantly more often in biopsies which revealed histological evidence of severe and irreversible histological injury. Binding of FAIgG was not selectively associated with any sex or age groups. Thus, detection of circulating immune complex-like materials in sera and the presence of glomerular deposits with antiglobulin activity were both features associated with severe glomerular injury. Both correlated with the quantity of complement deposited in the glomeruli. But only serum Clq binding activity was age and sex related. Similarly, in cancer patients, abnormal Clq BA were found more frequently in sera of older men with cancer but not in age- and sex-matched controls. Examination of selected sera by sucrose density gradient ultracentrifugation revealed that the complexes from cancer patients were relatively small (less than 19S greater than 7S) whereas those in most nephritis patients were heterogeneous in size. Sera with relatively high Clq binding activity from patients with chronic glomerulonephritis tended to contain relatively greater quantities of Clq binding materials sedimenting more rapidly than 19S.

Reduced renal acid excretion in malnutrition: a result of phosphate depletion.

Eleven infants recovering from protein-calorie malnutrition secondary to acquired monosaccharide intolerance were found to have reduced plasma bicarbonate concentration associated with inadequate weight gain. Renal net acid excretion (NAE) was decreased to a mean of 34.2 micronEq/1.73m2/min. Titratable acidity (TA) was markedly reduced, accounting for only 16% of NAE. This marked reduction in TA was associated with reduced mean phosphate (PO4) excretion (.074 mg/min) and a reduced mean serum PO4 (3.9 mg/dl), suggesting PO4 depletion. Two patients received intravenous phosphate loads, resulting in an increase in mean NAE from 35.1 to 89.7 microgEq/1.73m2/min. A similar response was seen after oral PO4 supplementation. Three patients were studied after partial correction of their acidosis. At a relatively low plasma bicarbonate concentration (mean = 16.6 mmoles/liter) significant amounts of bicarbonate were detected in the urine (mean = 8.7 micronEq/1.73m2/min), suggesting a defect in bicarbonate reabsorption. Five patients studied after complete recovery from malnutrition had normal NAE in response to ammonium chloride load. The reduction in NAE appears to be secondary to unavailability of urinary buffers and a reduction in bicarbonate reabsorption; both of these defects can be explained by phosphate depletion.

Severe hypertension, hyperkalemia, and renal tubular acidosis responding to dietary sodium restriction.

A 13-year-old girl with severe hypertension (240/140 mm Hg), short stature, marked hyperkalemia (8.6 mEq/liter), and renal tubular acidosis was studied. Renal parenchymal and renovascular diseases as well as endocrinologic causes of hypertension were ruled out by appropriate studies. The hypertension was associated with sodium retention, increased plasma volume, suppressed plasma renin activity, and decreased urinary excretion of aldosterone. Impaired renal excretion of potassium was demonstrated by sodium sulfate infusion when the patient was fed a high-sodium diet but a significant kaliuresis occurred when the test was performed on a low-sodium diet suggesting that renal sodium retention may play a role in the defect in potassium excretion. The renal tubular acidosis was associated with normal distal acidification but a low bicarbonate threshold (19 mmoles/liter) and marked suppression of urinary ammonium excretion. The hypertension, hyporeninemia, and hypoaldosteronism as well as the hyperkalemia and acid-base abnormalities were completely reversed by dietary sodium restriction or the administration of thiazides or furosemide. It is concluded that an unusual avidity for sodium chloride reabsorption by the renal tubules leading to extracellular volume expansion and renin-aldosterone suppression plays a significant pathogenic role in this syndrome and may explain the hypertension and biochemical abnormalities discussed.

Fas and Fas ligand interactions in malignant disease.

Apoptosis has been implicated in tumor development and progression. Fas (CD95) and Fas ligand (FasL) are an interacting receptor ligand pair that elicits apoptosis in many cell types. Although originally described as proteins regulating peripheral immune tolerance, accumulating evidence suggests that Fas/FasL may play an important role in carcinogenesis, tumor outgrowth, and metastasis. This review summarizes our current knowledge about the regulation of Fas and FasL expression, Fas signaling, soluble Fas production, the role(s) of Fas and FasL in hematopoietic and non-hematopoietic tumorigenesis and progression, and the potential application of Fas-induced apoptosis in cancer therapy.

The significance of focal glomerular sclerosis in children who have nephrotic syndrome.

This study was undertaken to learn the significance of focal glomerular sclerosis in children who have nephrotic syndrome. Tissue obtained by percutaneous renal biopsy 10-15 years previously was re-examined. Initially, two of the 29 biopsy specimens contained focal segmental hyalinosis or sclerosis and five of the 29 had focal glomerular obsolescence. The paraffin blocks were serially sectioned and examined. Following this procedure, seven of the 29 biopsies had focal segmented hyalinosis and 16 of the 29 had focal glomerular obsolescence. The percentages of focal segmental hyalinosis and focal glomerular obsolescence were recorded. Only those patients whose focal segmental hyalinosis exceeded 2% progressed to renal failure. Age-matched autopsy material from patients dying without renal dysfunction was used as a control. Focal glomerular sclerosis was seen in 75.8% of the control specimens, although few glomeruli within each specimen were involved. Focal glomerular sclerosis may be found normally; it may be found in nephrotic children who do not develop renal failure. The quantification of sclerotic lesions may be of prognostic significance in childhood nephrosis.

Focal glomerulosclerosis. Extent of involvement related to steroid resistance.

Biopsies were done for 27 nephrotic children whose presentations were compatible with minimal lesion nephrotic syndrome. Percentages of glomeruli involved by focal glomerular sclerosis and its subtypes were calculated. The presence or absence of interstitial disease was noted. These histologic findings were correlated with steroid responsiveness. All patients who had greater than 5% of glomeruli involved by focal glomerular sclerosis resistant to steroids. Interstitial disease was present in ten of the 27 patients studied; eight of the ten were resistant to steroids. Steroid resistance was found to be associated not with the mere presence of focal glomerular sclerosis but rather with its extent and the presence of interstitial disease.

Combined inhaled nitric oxide and inhaled prostacyclin during experimental chronic pulmonary hypertension.

Inhaled nitric oxide (NO) and inhaled prostacyclin (PGI2) produce selective reductions in pulmonary vascular resistance (PVR) through differing mechanisms. NO decreases PVR via cGMP, and PGI2 produces pulmonary vasodilation via cAMP. As a general pharmacological principle, two drugs that produce similar effects via different mechanisms should have additive or synergistic effects when combined. We designed this study to investigate whether combined inhaled NO and PGI2 therapy results in additive effects during chronic pulmonary hypertension in the rat. Monocrotaline injected 4 wk before study produced pulmonary hypertension in all animals. Inhaled NO (20 parts/million) reversibly and selectively decreased pulmonary artery pressure (Ppa) with a mean reduction of 18%. Four concentrations of PGI2 were administered via inhalation (5, 10, 20, and 80 microg/ml), both alone and combined with inhaled NO. Inhaled PGI2 alone decreased Ppa in a dose-dependent manner with no change in mean systemic arterial pressure. Combined inhaled NO and PGI2 selectively and significantly decreased Ppa more did than either drug alone. The effects were additive at the lower concentrations of PGI2 (5, 10, and 20 microg/ml). The combination of inhaled NO and inhaled PGI2 may be useful in the management of pulmonary hypertension.

Prevention of hepatitis B transmission in Indo-Chinese refugees with active and passive immunization.

Hepatitis B is a cause of disability and death worldwide, with high rates of perinatal transmission in third world countries, including those of Indochina. Prevention of transmission by active and passive immunization has been available since 1982. This study looked at the serological response of Indo-Chinese refugees to these products in an outpatient primary care clinic and at the compliance problems found in this setting. The carrier rate of all patients screened was 81/446 (18.5%), with 37/233 (15.8%) of prenatal patients as carriers. Newborns whose mothers were carriers were started on an immunization program. The combination of HBIG and vaccine was more than 90% effective in inducing immunity and preventing the carrier state; only two children of the 26 studied who received both active and passive immunization became carriers. Both failures were in children of HBeAg positive mothers. In contrast, those children exposed who had not received treatment (because of birth prior to 1982) had a 33% carrier rate. This success rate was found despite compliance problems in completing the immunizations on schedule. Only 23% of children received their vaccine within four weeks of the recommended schedule, with a mean delay of 1.3 months. Of the 79 children beginning immunizations, 11 moved before completion. All children remaining in San Diego completed the regimen. Thus, the benefits of giving the passive and active immunization to infants of hepatitis B carriers were clear. However, compliance problems jeopardize the effectiveness of a hepatitis B immunization program in this population.(ABSTRACT TRUNCATED AT 250 WORDS)

A model immunization demonstration for preschoolers in an inner-city barrio, San Diego, California, 1992-1994.

An immunization demonstration project was conducted in an inner-city Latino neighborhood in San Diego to address underimmunization of children of preschool age. The project attempted interventions on consumer, provider, and system levels to reduce barriers to immunization and raise immunization rates. Free walk-in immunization clinics with emphasis on cultural sensitivity and that incorporated computerized reminder/recall were established. An educational series was offered to community health center (CHC) providers, and extensive community-based outreach and education took place in schools, churches, a WIC site, etc. Evaluation activities included preintervention and postintervention provider knowledge, attitudes, and practice surveys, CHC chart audits, and household surveys in the intervention ZIP code area and a control ZIP code area. Immunization coverage for 4DPT, 3OPV, and 1MMR (4:3:1) among two-year-olds increased significantly from 37% to 50% overall, and to 59% in the 1991 birth cohort in the intervention area compared to a one percentage point overall increase in the control area. Coverage improved significantly and missed opportunities decreased in one intervention CHC that participated most actively in educational inservices. While the Year 2000 U.S. Public Health Service objective of 90% 4:3:1 coverage for two-year-olds was not achieved over the 21-month course of the project, the results approached the 1996 single-antigen objectives. This demonstration underscores the importance of multilevel interventions including low cost, no appointment, and culturally appropriate immunization services for the indigent; the use of computerized reminder systems; and provider assessment, education, and feedback in the effort to raise preschool immunization levels. Medical Subject Headings (MeSH): immunization, preschool-age children, health promotion, provider education, immunization monitoring and follow-up systems, pediatric immunization standards, household surveys.

Diagnostic and prognostic significance of glomerular epithelial cell vacuolization and podocyte effacement in children with minimal lesion nephrotic syndrome and focal segmental glomerulosclerosis: an ultrastructural study.

Children with minimal lesion nephrotic syndrome (MLNS) may later develop focal segmental glomerulosclerosis (FSGS). It has been suggested that a low percentage of epithelial podocyte effacement (EPE) and a high degree of epithelial cell vacuolization (ECV) in nonsclerotic glomeruli presage FSGS, and that extensive epithelial cell vacuolization in biopsies clearly showing FSGS predicts a poor clinical outcome. To investigate these contentions, we examined by electron microscopy three glomeruli from each of the first biopsies of 30 patients. Ten patients (group 1) had MLNS, 10 (group 2) had FSGS, and 10 (group 3) had MLNS which progressed to FSGS. Clinical data was obtained by retrospective review of medical records. The percent of epithelial podocyte effacement was calculated by computerized linear tracing and epithelial cell vacuolization was scored semiquantitatively from 0-3. (formula; see text) The percent podocyte effacement in each group was the same and does not distinguish MLNS from FSGS. Group 2 had more extensive epithelial cell vacuolization than group 1 (p less than 0.04) and the same as group 3 (p = 0.16). The combined ECV score for groups 2 and 3, however, was significantly greater than for group 1 (p less than 0.025) suggesting that epithelial cell vacuolization may indeed be a marker of FSGS. The extent of epithelial cell vacuolization did not correlate with creatinine clearance at latest follow-up, and thus does not predict clinical outcome.

Mesangial IgG in childhood minimal change disease: clinical relevance.

The clinical courses of five children with the nephrotic syndrome and renal biopsies diagnosed as minimal change disease (MCD) by light microscopy but with mesangial immune deposits of IgG (> or = 2+) and no dominant or codominant IgA were reviewed retrospectively to determine if the presence of significant mesangial deposits of IgG has prognostic implications and to evaluate the treatment these patients received. All five of the children were steroid dependent or resistant initially, and four received cyclosporine or cytotoxic agents later. After a mean follow-up period of 2.9 years for four and 20 years for one, all are in remission. All have normal renal function with no hypertension. These results suggest that the deposition of IgG in the mesangium of biopsies from patients with MCD by light microscopy may predict a more difficult course initially and may require more aggressive treatment to achieve permanent remission.

Body composition, normal electrolyte concentrations, and the maintenance of normal volume, tonicity, and acid-base metabolism.

Because the internal environment of the body is largely a fluid medium, the preservation of the volume and composition of the body fluids is absolutely vital to circulatory status and the extraordinarily complicated functions of the human body. The fluid compartments do not exist as fixed spaces with identical compositions but rather are in constant interchange with each other and have strikingly different compositions. Methods of movement of solutes and water include diffusion along electrochemical gradients, by hydrostatic pressure, osmotic forces, bulk flow, primary and secondary active transport, capillary blood flow, and oncotic pressure. Complex feedback control mechanisms exist to ensure homeostasis or equilibrium and include participation by the kidneys, lungs, gastrointestinal tract, the circulatory system, the endocrine system, and the CNS. The maintenance of extracellular volume is centered around the control of balance of the sodium salts. Multiple afferent (or sensing) and efferent (or effector) mechanisms exist to accomplish this homeostasis. The most important determinants of the osmolality or tonicity of the body fluids is the excretion or retention of water by the kidney, thirst mechanisms, and the intake of water. The serum sodium concentration is the laboratory test most often used clinically to assess tonicity. The pH of the body fluids and the major acid-base buffer systems are also carefully regulated. The lungs are responsible for the elimination of the carbon dioxide produced by cellular metabolism, and the kidneys excrete hydrogen ions and regulate the concentration of bicarbonate in the body fluids. Urinary net acid excretion, the hydrogen ions excreted as titratable acid and ammonium ions minus any bicarbonate, equals the acid added to the ECF from the diet and metabolism plus any fecal losses of alkali.

The specificity of split renal membranes in hereditary nephritis.

This study was undertaken to assess the specificity of split renal basement membranes in hereditary nephritis (HN). Thirteen specimens from eight patients with HN were mixed in a random fashion with specimens from control patients with either idiopathic nephrotic syndrome or various forms of glomerulonephritis and with specimens from patients with benign recurrent hematuria (BRH). Each biopsy specimen was scored for splitting of glomerular basement membranes (GBMs). Control and BRH specimens contained focal splitting in the GBMs; the biopsy specimens from HN patients had widespread lesions. Evaluation of split GBMs is useful in differentiating patients with HN from those with BRH and other renal diseases that may be confused with HN.

Hyponatremia in hospitalized children.

To determine the frequency, causes, and clinical significance of hyponatremia in hospitalized children, we reviewed the clinical and laboratory data of all hyponatremic children in Texas Children's Hospital over a 12-month period. One hundred sixty-one patients from among 11,702 hospital admissions were found to have hyponatremia, defined as serum sodium value of less than 130 mEq/L, an overall frequency of 1.38%. Sixty-nine patients (43%) had hyponatremia on admission, and 92 patients (57%) had hospital-acquired hyponatremia. Thirty-seven (23%) were previously healthy children, and 124 (77%) had chronic illnesses. Acute gastroenteritis was the leading cause of hyponatremia present on admission, and diuretic therapy was the leading cause of hospital-acquired hyponatremia. Only four patients (2.5%) had a serum sodium concentration of less than 120 mEq/L. Six patients (3.7%) had neurologic impairment on discharge, and 19 patients (12%) ultimately died long after their hyponatremia was corrected. Each patient who had neurologic sequelae and each patient who died had underlying medical conditions which could explain their morbidity and/or mortality. The prognosis appears to be more clearly related to the underlying medical disorder rather than to the hyponatremic state or its correction.