Effects of hydroxyapatite particulate debris on the production of cytokines and proteases in human fibroblasts.

Cytokines and proteases are secreted by fibroblasts in response to particulate wear debris, and these proteins are felt to play an important role in the development of osteolysis and implant loosening. Although metallic and polyethlyene debris have been studied extensively, little is known about the cellular responses to hydroxyapatite, despite the wide clinical use of these materials. Therefore, the effects of hydroxyapatite (HA) and hydroxyapatite/beta-tricalciumphosphate (HA/TCP) on cellular proliferation, cytokine gene expression and protein secretion, protease synthesis, and gelatinolytic activity were investigated in human fibroblasts. HA and HA/TCP particles were synthesized, and their effects were compared to the responses elicited by titanium and cobalt chromium. Sample characterization by scanning electron microscopy and Coulter Counter demonstrated that the materials had a mean particle size of less than 10 microm, and all of the particles were compared using the same concentration ranges. Aliquots of particle suspensions were added to human fibroblasts maintained in tissue culture, and dose-response and time-course experiments were performed. Effects of the particles on fibroblast proliferation were assessed, and alterations in cytokine levels were determined by specific enzyme linked immunosorbent assays (ELISA). Cytokines that were evaluated included interleukin-1 (IL-1beta), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha), all of which have been demonstrated to enhance bone resorption and are associated with osteolysis and implant loosening. Gene expression was determined using Northern blot analysis with cytokine-specific probes, while secretion of the proteases collagenase and stromelysin was determined by Western blot analysis. Functional gelatinolytic assay was assessed using zymogram gels. The particles were evaluated in a concentration range from 0.000021 to 0.021 vol%. All of the particles produced increases in cellular proliferation up to 0.0021 vol%, with the largest increases being seen at 0.021 vol% with HA/TCP and titanium. At the highest concentration, both cobalt chromium and HA samples decreased cellular proliferation relative to lower doses, possibly representing cytotoxicity. Hydroxyapatite particles yielded a 30-fold increase in interleukin-6 secretion compared to unstimulated controls, which was also greater than three times the levels produced by cobalt chromium, titanium, or HA/TCP. HA particles also tripled the secretion of IL-1beta at 0.00021 vol%, and doubled TNF-alpha secretion at 0.021 vol%. Addition of conditioned media prepared by incubation of the particles in culture medium in the absence of cells did not alter the secretion of any of the cytokines. Northern blot analysis using IL-6 probes also demonstrated strong increases with HA compared to the other materials, suggesting that the action of the HA particles was at the level of transcription. Secretion of the protease collagenase was increased by all of the samples including HA when compared to unstimulated controls. Stromelysin secretion into the culture medium was decreased by cobalt chromium, but increased by titanium, HA, and HA/TCP. All of the particles including HA increased the gelatinolytic activity of the fibroblasts. These findings demonstrate that HA and HA/TCP particles are capable of stimulating the expression and secretion of cytokines and proteases that enhance bone resorption, and suggest that particulate debris from implants using these coatings may also increase osteolysis and loosening.

Salmonella virchow meningitis in an adult.

We report here a case of meningitis caused by Salmonella virchow in a woman without signs or history of immunosuppression. Salmonella meningitis is a rare complication of human salmonellosis. The patient was successfully treated with ciprofloxacin. To our knowledge, this is the first reported case of confirmed meningitis in an adult caused by this serotype.

The anti-HBs response after 2 different accelerated intradermal and intramuscular schemes for hepatitis B vaccination.

To study early seroconversion rates after hepatitis B vaccination intramuscular (i.m.) and low-dose intradermal (i.d.) vaccination was compared when given either according to the registered 0, 4, 8 weeks scheme (scheme A), or to an accelerated 0, 2, 6 weeks scheme (scheme B). Medical staff received either 2 microg i.d. or 20 microg i.m. of a recombinant hepatitis B vaccine, in a non-randomized open trial. Two weeks after the third dose i.m. vaccinees overall had significantly higher rates of protective anti-HBs levels (anti-HBs > or = 10 IU/I), (23/30, 77%) compared with i.d. vaccinees (75/166, 45%) (p < 0.001). We conclude that when rapid protection against hepatitis B virus (HBV) infection is desirable, such as for post-exposure prophylaxis, an accelerated low-dose i.d. vaccination schedule cannot be used.

Microsporidia in duodenal biopsies from 72 HIV-infected patients with abdominal complaints.

In order to evaluate the capacity of routine histological examination to detect microsporidiosis, a retrospective study was performed on 72 duodenal biopsies from 72 HIV-infected patients with upper abdominal symptoms of unknown cause. Two light microscopic cytological staining techniques, modified trichrome stain and the fluorochrome Calcofluor, were used. Two cases of microsporidiosis were detected among the 20 patients with prolonged diarrhoea of unknown origin in whom no etiological agent had been demonstrated by stool examination, mycobacterial and cytomegalovirus culture of biopsies, and histological routine staining of duodenal biopsies. The calculated confidence interval of 3-30% corresponds to the prevalence of intestinal microsporidiosis in HIV patients with prolonged diarrhoea in various parts of the world. The findings motivate attempts to identify microsporidia using special cytological staining methods. Improved methods of species identification are needed to aid in the choice of chemotherapy.

Prevalence and risk factors for HTLV-II infection in 913 injecting drug users in Stockholm, 1994.

The prevalence and risk factors for acquisition of human T-cell lymphotropic virus type I and II (HTLV-I and II) were investigated in a prospective study of 913 injecting drug users (IDUs) in Stockholm in 1994. Epidemiologic data were recorded, and blood samples were tested for antibodies against HTLV-I and HTLV-II; human immunodeficiency virus (HIV) types 1 and 2; and hepatitis A (HAV), B (HBV), C (HCV), and D (HDV). Positive serologic results for HTLV were confirmed by Western blot (WB) and polymerase chain reaction (PCR). Of the 905 participants with conclusive HTLV-II status, 29 (3.2%) were HTLV-II positive, and all but three were of Nordic descent. None was HTLV-I infected. One person was infected as early as 1981, before HIV had reached the IDU population in Sweden. The prevalence of HTLV-II infection was 12% among HIV-1-seropositive and 1.8% among HIV-1-seronegative participants. The overall seroprevalences were 14% for HIV-1, 0% for HIV-2, 41% for HAV, 75% for HBV, 92% for HCV, and 8% for HDV. Although amphetamine has been the main injecting drug in Sweden for several decades, heroin abuse combined with a debut of injecting drugs before 1975 was identified as the most important risk factor associated with HTLV-II infection. HAV and HIV seropositivity were also independent risk factors.

The consultation.

PIP: The author of this critique is a family physician who was asked for an abortion referral. His patients said that she wanted an abortion because she suffered from a chronic disease which required constant medication (she feared that the baby would be harmed by this circumstance). The physician consulted a geneticist and a perinatologist and assured the woman that neither the disease nor the medication should harm the fetus. Then the woman confessed that she was a single mother and wanted the abortion because of socioeconomic distress. The physician told the woman he could not refer her for an abortion but that others could. After he left the consulting room, a nurse told him that the woman, who was in tears, wanted to talk to him again. He gave her the name of an antiabortion counseling agency and suggested that he meet with her again in a week. She never returned. The usual response of a physician to a woman desiring an abortion is to give her a referral to an appropriate facility where she will receive counseling to determine if she really wants the abortion. Abortion is not rare in the US. Since 1975, abortions have been performed at an almost constant rate of 354/1000 live births. The present system of abortion on demand fails to place enough weight on the values of self-sacrifice or on communal sharing of hardship. Rather than performing abortions based on expediency, physicians must offer women with unwanted pregnancies community counseling and access to social resources.^ieng

Utility of an anonymous questionnaire for the identification of a primary transmission route and possible secondary transmission in adults with acute hepatitis B virus infection.

By letting adults with acute hepatitis B virus (HBV) infection answer an anonymous questionnaire covering risks associated with the acquisition and further transmission of HBV infection, we found that a likely relevant transmission route could be identified in most patients. Despite being informed of the diagnosis, 50% of the patients exposed others via sexual contact during their contagious period.

Specific inhibition of basic calcium phosphate and calcium pyrophosphate crystal-induction of metalloproteinase synthesis by phosphocitrate.

Calcium pyrophosphate dihydrate (CPPD) and basic calcium phosphate (BCP) crystal deposition diseases are a group of heterogeneous arthritides which are a significant source of morbidity in the elderly. Both crystals induced mitogenesis and metalloproteinase (MP) synthesis and secretion by fibroblasts and chondrocytes which may promote degradation of intra-articular tissue. We have previously shown that phosphocitrate (PC), an inhibitor of hydroxyapatite crystallization, specifically blocks BCP crystal-induced mitogenesis in 3T3 cells. This led us to examine the effect of PC on BCP and CPPD crystal induction of MP synthesis in human fibroblasts. PC (10(-3) to 10(-4) M) specifically inhibited the crystal-induced collagenase and stromelysin mRNA accumulation while having no effect on epidermal growth factor-induced or basal levels of mRNA for both enzymes. Western blots (collagenase) of conditioned media confirmed that PC blocked crystal-induced proteinase secretion as well. Moreover, PC (10(-3) M) also blocked the crystal induction of c-fos and c-jun. Since FOS and JUN proteins form a transacting activator (AP-1) for expression of collagenase and stromelysin genes, PC may block the synthesis of both enzymes by inhibiting the transcription of c-fos and c-jun.

Risk factors for hepatitis A, B and C virus infection among Swedish expatriates.

The influence of different risk factors for viral hepatitis A, B and C, particularly if sexual contact with the indigenous population was related to an increased risk of having hepatitis B virus (HBV) markers, was assessed by multivariate analysis in a logistic regression model in a prospectively enrolled series of 563 adult Swedish expatriates. The most frequently reported recognised risk factors for the acquisition of viral hepatitis (as reported in a self-administered questionnaire) were having received an inoculation during medical or dental treatment, reported by 45% of all subjects, and having had sexual contact with the indigenous population, reported by 35%. Whilst the prevalences of hepatitis A virus (HAV) and hepatitis C virus (HCV) markers in these expatriates were of the same magnitude as previously reported in the general Swedish population, 8% and 0.3%, respectively, the prevalence of markers for a past or present HBV infection was about twice as high (5%). The presence of HBV markers was associated with being a health care professional or having received inoculations during medical or dental treatment in Africa. No significant association was found between having HBV markers and having had sexual contact with the indigenous population.

Response to a booster dose 18 months after a low anti-HBs response (10-99 IU/l) to three doses of intradermally or intramuscularly administered recombinant hepatitis B vaccine.

The response to a booster dose, given by the same route 18 months after the completion of the primary vaccination scheme, was studied in hospital staff members who responded with anti-HBs levels in the range of 10-99 IU/l after three intradermal (i.d., n = 51) or intramuscular (i.m., n = 11) doses of recombinant hepatitis B virus (HBV) vaccine administered at 0, 1 and 6 months. At the time of boostering the anti-HBs levels had declined to < 10 IU/l in 44/51 (86%) of the i.d. and 10/11 of the i.m. vaccines. All i.m. and 90% of i.d. vaccinees responded to the booster dose with anti-HBs level > or = 10 IU/l, and with geonmetric mean titres 1,074 IU/l and 121 IU/l, respectively. It was concluded that all i.m. and 90% of i.d. vaccinees with an initial anti-HBs response of 10-99 IU/l after three doses of HBV vaccine (among whom the anti-HBs levels in the majority had declined < 10 IU/l) mounted an anti-HBs level > or = 10 IU/l after a booster dose. The anti-HBs concentrations were generally higher after i.m. than i.d. booster doses in accordance with the response to primary vaccination.

Nosocomial calicivirus gastroenteritis in a pediatric hospital.

At St. Göran's Children's Hospital (a tertiary center), we perform electron microscopy of feces in most cases of nosocomial gastroenteritis. From September 1987 through April 1992 we identified 32 episodes of calicivirus infection, 25 of which were nosocomial and, except for one outbreak, sporadic. Systematic study of the nosocomial outbreak of calicivirus gastroenteritis from November 1991 to January 1992, revealed calicivirus in the stools of 8 of 23 children with diarrhea and 0 of 10 without diarrhea. In 3 of 7 sampled after cessation of diarrhea, calicivirus excretion continued for 3 to 6 days. We found no calicivirus in 42 staff members or 9 members of infected patients' families. Nosocomial transmission of calicivirus can occur among infants.

Prevalence of antibodies against hepatitis C virus infection among health care workers in Stockholm.

The prevalence of hepatitis C virus (HCV) markers was investigated among health care staff with a high rate of exposure to blood or needle-stick injuries. After screening sera in pools of 10 at a time and individual testing of all reactive pools, totally 6 of 880 (0.7%; 95% confidence interval, 0.25-14.8%) were positive for anti-HCV, a figure of the same order as that found among Swedish first-time blood donors. Among the seropositives, all of five evaluable had been exposed to blood and four of five to needle-stick injuries. Our data suggest that HCV, in addition to hepatitis B virus, may constitute an occupational hazard for health care workers in Stockholm, even though the risk appears to be low, and personal risk factors such as intravenous drug abuse or blood transfusion could not be ruled out as sources of the infection.

Seroconversion after additional vaccine doses to non-responders to three doses of intradermally or intramuscularly administered recombinant hepatitis B vaccine.

Hospital staff members who failed to respond (anti-HBs < 10 IU/l) after 3 doses of a recombinant hepatitis B (HBV) vaccine (given either as 20 micrograms intramuscularly (n = 8) or 2 micrograms intradermally (n = 15)) received 1 or 2 additional doses by the same route as the initial vaccination. After the first additional dose, 12/23 responded with anti-HBs levels > or = 10 IU/l and after the second, another 2/5 responded, corresponding to a total response rate of 61%. No significant difference was seen in the response rate according to vaccination route, gender, age, or whether the vaccinee was a smoker or not. In this limited study some 50% of non-responders to 3 intradermal or intramuscular doses of recombinant HBV vaccine seroconverted after an additional 1-2 doses given by the same route as the initial vaccination, suggesting that additional doses can be administered by the same route as the initial one.

[Offer hepatitis B vaccination to the addicts. Transmission of hepatitis B among intravenous drug abusers]. / Erbjud missbrukare hepatit B-vaccination. Spridning av hepatit B bland sprutnarkomaner.

Structured interviews with 75 intravenous drug abusers (IVDAs) in Stockholm showed that, despite their having had several contacts with various medical institutions or prisons, none had been offered vaccination against hepatitis B virus (HBV) infection as recommended by the National Board of Health and Welfare. We conclude that, as failure to offer HBV vaccination to IVDAs contributes to be continued spread of HBV infection in this category, at admission all IVDAs should undergo serological HBV-testing and vaccination be offered to HBV-negatives.

Prevalence of hepatitis B virus markers among intravenous drug abusers in Stockholm: impact of heterosexual transmission.

In order to study the importance of sexual transmission of hepatitis B virus (HBV) among intravenous drug abusers (IVDAs), and from IVDAs to others, we consecutively interviewed 171 IVDAs detained at the Stockholm Remand Prison during 4 months in 1990. Sexual histories revealed that 77% reported > or = 3 sexual partners during the last 3 years, 64% had had a sexual partner who did not inject drugs, and 61% reported a prior STD. The prevalence of HBV markers was 75%. In a multiple logistic regression analysis, a high risk for HBV markers was associated with an increasing duration of drug abuse, a high prevalence of hepatitis A markers, and an increasing number of drug injecting sexual partners during the last 3 years, indicating that sexual transmission, along with sharing of needles, may contribute to the high prevalence of HBV markers within this group. It is suggested that an adequate sexual history must be obtained from IVDAs with acute viral hepatitis in order to identify sexual partners who should be offered postexposure prophylaxis, and that non-immune IVDAs should be vaccinated against viral hepatitis A and B.