Recruitment of osteoclast precursors by purified bone matrix constituents.

The osteoclast, the multinucleated giant cell of bone, is derived from circulating blood cells, most likely monocytes. Evidence has accrued that is consistent with the hypothesis that the recruitment of monocytes for osteoclast development occurs by chemotaxis. In the present study, we have examined the chemotactic response of human peripheral blood monocytes and related polymorphonuclear leucocytes to three constituents of bone matrix: peptides from Type I collagen, alpha 2-HS glycoprotein, and osteocalcin (bone gla protein). The latter two substances are among the major noncollagenous proteins of bone and are uniquely associated with calcified connective tissue. In chemotaxis assays using modified Boyden chambers, Type I collagen peptides, alpha 2HS glycoprotein, and osteocalcin evoke a dose-dependent chemotactic response in human monocytes. No chemotaxis is observed on PMNs despite their ontogenetic relationship to monocytes and their documented sensitivity to a broad range of other chemical substances. Our observations are consistent with the view that osteoclast precursors (monocytes) are mobilized by chemotaxis, and suggest that the chemoattractants responsible for this activity are derived from the bone matrix or, in the case of collagen and osteocalcin; directly from the osteoblasts which produce them.

Bone matrix constituents stimulate interleukin-1 release from human blood mononuclear cells.

To test the hypothesis that mononuclear cells are stimulated to release interleukin 1 (IL-1) by bone fragments released in the bone microenvironment during the remodeling cycle, we have investigated the effects of bone matrix and some of its constituents on IL-1 secretin from peripheral blood mononuclear cells (PBMC). Increases in IL-1 activity were observed when either PBMC or adherent monocytes, but not lymphocytes depleted of monocytes, were co-cultured with either human or rat bone particles but not with latex particles of similar size. Co-culture of PBMC with bone particles in a transwell system where the cells were physically separated from the bone particles, or with osteoblast- or osteoclast-covered bone particles, did not stimulate IL-1 release, indicating that a physical contact between PBMC and the bone surface is required for eliciting IL-1 release. This was confirmed by the finding of a lower stimulatory effect of bone particles pretreated with etidronate, a bisphosphonate which decreases the bone binding capacity of PBMC. Constituents of bone matrix, such as collagen fragments, hydroxyproline, and, to a lesser extent, transforming growth factor-beta, but not osteocalcin, alpha 2HS glycoprotein, fragments of either bone sialoprotein or osteopontin, and fibronectin, stimulated PBMC IL-1 release in a dose-dependent fashion. Collagen-stimulated IL-1 release was partially and specifically inhibited by a monoclonal antibody directed against the alpha 2 beta 1-integrin cell surface collagen receptor. These data demonstrate that products of bone resorption, known to be chemotactic for mononuclear cells, stimulate PBMC IL-1 activity. These findings may help explain previous documentation of increased IL-1 secretion by circulating monocytes obtained from patients with high turnover osteoporosis.

Anthrax as a potential biological warfare agent.

Anthrax is a zoonotic illness recognized since antiquity. Today, human anthrax has been all but eradicated from the industrialized world, with the vast majority of practitioners in the United States unlikely to have seen a case. Unfortunately, the disease remains endemic in many areas of the world, and anthrax poses a threat as a mass casualty-producing weapon if used in a biological warfare capacity.

Aging and the kidney.

Numerous anatomic and physiologic alterations occur in the kidney with aging. These changes affect the ability of elderly patient(s) to maintain homeostasis and alter response to medications, stress, illness, or changes in diet, mobility, or environment. Drug-induced illness and drug interactions are major problems in the elderly. Bone disease and fractures are associated with negative calcium balance and decreased production of 1,25-dihydroxycholecalciferol seen with aging. The geriatric patient is not immune to the primary glomerular diseases that occur in younger patients, although the relative incidence of pathologic diagnoses may differ. The high incidence of membranous glomerulonephritis in the elderly, and the well-known association between malignancy and membranous nephropathy strongly favor aggressive evaluation of the nephrotic syndrome in the geriatric age group. Attention must be given to consideration of appropriate end-stage renal disease treatment alternatives for the geriatric population, which now comprises the fastest-growing segment of the end-stage renal disease population.

Glucocorticoid enhancement of bone resorption by rat peritoneal macrophages in vitro.

The issue of the direct action of glucocorticoids on bone resorption was addressed in a model system consisting of a pure (99%) population of putative osteoclast precursors, namely thioglycollate-elicited rat macrophages cocultured in vitro in devitalized rat bone particles which had been prelabeled in vivo with 45Ca. After 4 days in culture, these macrophages mobilized a net 20-30% 45Ca from bone. The addition of cortisol in physiological concentrations (10(-8) M) elicited significant (P less than 0.001) increases in isotope mobilization; optimal enhancement occurred at 10(-6) M and approximated the circulating level achieved with high dose glucocorticoid therapy. Other steroids, specifically aldosterone, 17 alpha- and beta-estradiol, 11-deoxycortisol, and progesterone, did not enhance the resorptive process. The augmentation of bone 45Ca mobilization by cortisol-treated macrophages was not due to protracted cell viability in culture or the increased avidity with which treated cells bind to bone. On the other hand, cortisol treatment was associated with stimulated protein and RNA synthesis, as evidenced by enhancement (P less than 0.001) of both [3H]leucine and [3H]uridine incorporation into treated cells. This association was also underscored by the observation that increased protein and RNA synthesis and enhanced mineral mobilization were inducible phenomena, i.e. phenomena that could be observed 48-72 h after cells were pretreated with cortisol. We conclude, therefore, that glucocorticoids can directly modify both the metabolism and the mineral-mobilizing activity of bone-resorbing cells.

Comparative evaluation of six rapid serological tests for HIV-1 antibody.

Six commercial rapid test kits for HIV-1 antibody were evaluated. Four laboratory technologists tested sera from four groups of U.S. military personnel or dependents: 202 subjects positive for HIV-1 antibody by Western blot, 200 seronegative voluntary blood donors, 199 seronegative obstetrics/gynecology patients, and 99 subjects with sera reactive by ELISA but negative by recombinant protein EIA and indeterminate by Western blot. The three tests using solid-phase immunoassay technology demonstrated the highest mean sensitivity (> 99%) and specificity (> 91%) for all groups tested, including sera indeterminate by Western blot. Two dot-immunoblot assays were less specific, possibly due to indistinct reaction end points, and a latex agglutination assay was also less specific because of difficulty distinguishing reactive results from the granular background. In an "ease-of-use" assessment, solid-phase capture immunoassays required less time and equipment and were easier to interpret than other testing methods. Solid-phase capture immunoassays for HIV-1 antibody may be suitable for use in emergency situations and in developing countries because they are highly sensitive and specific and are rapidly performed with minimal laboratory equipment.

The risk of Helicobacter pylori infection among U.S. military personnel deployed outside the United States.

To determine whether military personnel deployed outside the United States are at increased risk of Helicobacter pylori infection, 1,000 male U.S. Navy and Marine Corps personnel (mean age 22 years) were evaluated. Study subjects included 200 recruits, 500 shipboard personnel deployed for six months to South America, West Africa, and the Mediterranean, and 300 ground troops deployed for five months to Saudi Arabia. Among all 1,000 subjects, 247 (25%) were seropositive for H. pylori IgG antibody by an enzyme-linked immunosorbent assay; 24% of new recruits and 25% of troops who had been on active duty for a mean of four years. The prevalence of H. pylori antibody was higher among subjects who were older, nonwhite, foreign-born, and seropositive for antibody to hepatitis A virus. Among the 601 initially seronegative subjects evaluated before and after a 5-6 month deployment outside the United States, five seroconverted, for a rate of infection of 1.9% per person-year of exposure. As found in other populations in developed countries, these data indicate that among U.S. military personnel a large proportion of H. pylori infections occur before adulthood and infection is related to demographic factors. These preliminary findings also suggest that deployed U.S. military personnel may be at increased risk of H. pylori infection compared with adult populations in developed countries either from exposure in developing countries or from crowding.

Falciparum malaria in a displaced Haitian population.

Falciparum malaria was a major problem among displaced Haitians in temporary camps at the US Naval Base, Guantanamo Bay, Cuba. From December 1991 to March 1992, 235 cases of unmixed falciparum malaria were diagnosed in the laboratory, giving a cumulative attack rate of 160 per 10 000 camp residents. All cases were successfully treated with oral chloroquine. Children under 16 years of age, and especially females, were at substantially higher risk of infection (attack rate 481/10 000 versus 278/ 10 000 for males in the same age range). Malaria attack rates by place of birth in Haiti were calculated per 10 000 people as Cayemite, 530; Baraderes, 375; Pestel, 285; Port Au Prince, 247; and La Gonave, 36. The time to onset of clinical malaria after embarking at the Naval Base ranged from one to 58 d. No malaria transmission was demonstrated in the migrant camp. A non-systematic survey showed a 1.7% prevalence (95% confidence interval +/- 1.9%) of falciparum malaria among asymptomatic residents. Health practitioners in areas that may receive Haitian migrants should plan to care for malaria and preventive medicine measures are indicated, as imported malaria could be transmitted in areas where competent vectors are indigenous.

Leishmaniasis among Desert Storm veterans: a diagnostic and therapeutic dilemma.

Troops stationed in the Middle East during Operations Desert Shield/Storm were potentially exposed to leishmaniasis, a parasitic infection transmitted by sandflies. In this region, infection primarily causes cutaneous and, less often, visceral disease. Visceral leishmaniasis, which typically has an incubation period of several months, can be a difficult diagnosis as it presents with a wide range of symptoms and there are no non-invasive, reliable diagnostic tests. Cutaneous leishmaniasis is more easily diagnosed using culture and stained smears of biopsy and aspirate samples from skin lesions. Pentavalent antimonials are most often used to treat leishmaniasis; however, treatment is potentially toxic and not recommended except in cases of documented disease.

A survey of women's health care needs on U.S. Navy ships.

A total of 628 female and 526 male U.S. military personnel completed a health survey questionnaire at the completion of four shipboard deployments lasting 10 to 180 days (mean, 57 days). During deployment, women visited clinic (sick call) at significantly higher rates than men: 189 versus 117 visits per week per 1,000 personnel. Except for generally minor gynecological conditions, women and men had similar medical problems. Upper respiratory complaints and requests for contraceptive pills were the most common reasons for clinic visits among women. The majority of sailors felt that they had received appropriate medical care, although fewer women (66%) than men (78%) were satisfied. Levels of cigarette and alcohol use and sexual activity were comparable among women and men and corresponded to those of the general U.S. population of young adults. Because of high levels of health, most medical needs of women sailors can be managed readily by providing routine gynecological care and by minor additions to the shipboard pharmacy.

Clinical prognosis of patients with early-stage human immunodeficiency virus (HIV) disease: contribution of HIV-1 RNA and T lymphocyte subset quantitation.

Systems for the staging of individuals with human immunodeficiency virus type 1 (HIV-1) infection were developed 15 years ago. Subsequently, assays for quantitating HIV-1 RNA and immunophenotyping of lymphocyte subsets have been developed and validated. The utility of these assays for improved staging in early disease was evaluated in 256 HIV-infected adults (52% minority) with CD4 counts > or = 400 cells/microL followed in U.S. military medical centers before the highly active anti-retroviral therapy era. HIV viral load (RNA) was quantitated; the frequencies of select CD4+ immunophenotypes were determined in 112 subjects. The results were analyzed in relation to three outcome measures: death, first acquired immunodeficiency syndrome-defining opportunistic infection, and CD4 count < or = 200 cells/microL. Serum RNA level and CD4 count were each found to be predictive of all three outcomes. In addition, increases in the T-cell subsets CD28-CD4+ and CD29+CD26-CD4+ were found to be independently predictive of more rapid progression. The classification of early-stage HIV patients is improved by the quantitation of both viral RNA and T-lymphocyte subsets.

alpha 2HS glycoprotein is chemotactic for mononuclear phagocytes.

alpha 2HS glycoprotein is a normal constituent of plasma. It has a high affinity for hydroxyapatite and is concentrated in bone 100-fold greater than albumin, however its biological function in bone is not known. We have purified alpha 2HS from human plasma and examined it for evidence of chemotactic activity against human peripheral mononuclear cells, polymorphonuclear leucocytes and lymphocytes in Boyden chamber assays. We observed that the protein was chemotactic for mononuclear cells and that maximal cell migration occurred when its concentration in the lower compartment of Boyden chambers was 10(-10) M. Chemotaxis did not occur in the absence of a concentration gradient. In addition, cell migration was blocked when the cells were preincubated with 10(-10) M alpha 2HS or when the protein was preincubated with rabbit anti-human alpha 2HS glycoprotein IgG. Neither polymorphonuclear leucocytes, which are responsive to a wide range of chemoattractants, or peripheral lymphocytes exhibited directed migration to alpha 2HS in Boyden chamber assays. The glycoprotein appears therefore to act as a chemotaxin directed to monocyte recruitment, and we speculate that the protein may have an important role in monocyte recruitment to bone and possibly their subsequent fusion and differentiation into functional osteoclasts.

Common variable hypogammaglobulinemia presenting as nontypable Haemophilus influenzae septic arthritis in an adult.

Haemophilus influenzae is a rare cause of septic arthritis in adults. We describe a case of septic arthritis with nontypable Haemophilus influenzae presenting as the first invasive infection leading to a diagnosis of common variable hypogammaglobulinemia. Although nontypable strains have been shown to cause serious infections in adults, they are a rare cause of septic arthritis. Underlying immune deficiency should be considered in an adult who presents with invasive infection with Haemophilus influenzae, regardless of serotype.

Recruitment of peripheral mononuclear cells by mammalian collagenase digests of type I collagen.

Type I collagen is highly susceptible to proteolytic cleavage by neutral mammalian collagenase. Following an initial site specific cleavage of the substrate, two characteristic products are generated, TCA and TCB. These two products then spontaneously denature and are degraded into multiple smaller molecular weight peptides. We prepared TCA and TCB from native type I collagen by the action of rat uterine fibroblast neutral collagenase. In addition we prepared denatured type I alpha chains and exposed them to the action of collagenase under controlled conditions in order to generate small molecular weight peptides. We then examined intact type I collagen, TCA and TCB and type I gelatin peptides for chemotactic activity in a Boyden chamber assay using both human peripheral monocytes and polymorphonuclear leucocytes as target cells. Intact type I collagen, while chemotactic for neutrophils, failed to elicit any chemotactic response in mononuclear cells. In addition, the results demonstrate an absence of any detectable chemotactic activity for either TCA or TCB when human peripheral monocytes were used as the target cells. However, type I collagen peptides demonstrated chemotactic activity for peripheral monocytes. Maximum cell migration was found with digests which had been exposed to neutral mammalian collagenase for three to four hours. No chemotactic activity was found using the same peptides, when neutrophils were used as the target cells. The data strongly suggest that chemotactic activity for mononuclear cells, normally suppressed in intact type I collagen, is revealed and/or activated by neutral collagenase digestion. Conversely, chemotactic activity for neutrophils is lost when intact type I collagen is digested into smaller molecular weight fragments.(ABSTRACT TRUNCATED AT 250 WORDS)

Human peripheral monocytes express putative receptors for neuroexcitatory amino acids.

Human peripheral mononuclear cells responded chemotactically to 4-carboxyl-L-glutamic acid. The maximal chemotactic response occurred at 0.1 nM. No chemotactic response was found with neutrophils or fetal bovine fibroblasts. Glutamic acid, a neuroexcitatory dicarboxylic amino acid and the parent compound of 4-carboxyglutamic acid, did not stimulate chemotaxis in any of the cells tested. However, it functioned as an antagonist to 4-carboxyglutamic acid (ED50 approximately 2 pM; ED100 approximately 10 pM). In contrast to the lack of response to glutamic acid, its dicarboxylic cyclic analogue, kainic acid, excited a chemotactic response in mononuclear cells. The data suggest that mononuclear phagocytes have receptors for dicarboxylic neuroexcitatory amino acids, and we speculate that 4-carboxyglutamic acid, a tricarboxylic acid, may have a previously unrecognized role as a neuroexcitatory amino acid.

Zinc in ulcerative colitis: a therapeutic trial and report on plasma levels.

A double-blind controlled trial of oral zinc sulphate as adjuvant treatment in idiopathic ulcerative colitis or proctitis in relapse is reported. Fifty-one patients were treated, and the clinical and sigmoidoscopic improvement in the zinc treated patients was similar to that in patients receiving placebo. No difference was found between plasma zinc levels in a further 46 patients with idiopathic ulcerative colitis or proctitis and those obtained in a group of healthy controls.

Ca2+ priming during vitamin D-induced monocytic differentiation of a human leukemia cell line.

1,25-Dihydroxyvitamin D3 (1,25-(OH)2D3) induces monocytic differentiation of the human promyelocytic leukemia line, HL-60, and enhances Ca2+ transport in target cells of the mineral metabolism system. Hence, we determined whether the steroid's maturational effect on HL-60 involves alterations of intracellular calcium [( Ca2+]i). We found that, as detected by indo-1 fluorescence, [Ca2+]i increases in a slow tonic manner from 99 +/- 11 nM in virgin HL-60 to 182 +/- 19 nM (p less than 0.001) in those treated with 1,25-(OH)2D3 for 24 h. The first apparent rise in [Ca2+]i occurs at between 6 and 12 h and parallels expression of alpha-thrombin and N-formyl-methionyl-leucyl-phenylalanine (fMLP) receptors. This increase in [Ca2+]i is derived from extracellular calcium as its reduction abolishes the effect. The increase in [Ca2+]i is associated with an increase in inositol trisphosphate-stimulated Ca2+ flux from intracellular stores. Interestingly, 1,25-(OH)2D3-mediated HL-60 differentiation as manifest by expression of the macrophage-specific antigen, 63D3, is not blocked by low extracellular calcium. In contrast, the fMLP-induced superoxide ion generation is diminished if the increase in [Ca2+]i is prevented. Furthermore, fMLP-stimulated signal transduction is also reduced by limiting the stimulation of [Ca2+]i during 1,25-(OH)2D3 treatment. Thus, although differentiation of HL-60 to the monocytic phenotype by 1,25-(OH)2D3 is Ca2+-independent, expression of response to regulatory stimuli requires priming of cellular Ca2+ stores. The latter appears to be induced by 1,25-(OH)2D3 via stimulated Ca2+ entry through the plasma membrane.