Allogeneic bone marrow transplantation for systemic AL amyloidosis

Low-intensity chemotherapy is ineffective in most patients with AL amyloidosis, probably because clinical benefit requires regression of the amyloid deposits, and this occurs only very gradually after the underlying plasma cell dyscrasia has been suppressed. We report the first successful allogeneic bone marrow transplant (allo-BMT) for AL amyloidosis, which after 3 years was associated with complete clinical recovery. This supports the idea that there may be a brief window of opportunity in patients with AL amyloidosis during which dose-intensive chemotherapy is feasible and most likely to produce clinical benefit.

Amyloidosis: a review of recent diagnostic and therapeutic developments

Amyloid deposition is associated with a diverse range of disorders that includes Alzheimer's disease, type II diabetes mellitus and dialysis arthropathy. Although less common, systemic AA and AL amyloidosis remain important because effective treatments have increasingly become available. The pathology in all forms of amyloidosis involves the extracellular deposition of protein as characteristic fibrillar aggregates which interfere with tissue structure and function. Amyloid fibrils are derived from different unrelated proteins in the different forms of the disease but share many common properties, including the capacity to bind the normal plasma protein serum amyloid P component (SAP). This is the basis for our development of radiolabelled SAP as a nuclear medicine tracer for the diagnosis and quantitative monitoring of amyloid. Serial studies have shown that the deposits are far from inert but are actually turned over quite rapidly in many patients. The treatment of amyloidosis involves supportive measures whilst every effort is made to reduce the supply of the respective fibril precursor protein. Under favourable circumstances further amyloid deposition will be prevented. existing deposits will regress and improvement of organ function will occur. Since this strategy is not always possible or may fail, new approaches to inhibit fibril formation and promote regression of amyloid are being pursued.

The role of transesophageal echocardiography in patients with chronic renal failure at low and high risk of endocarditis

BACKGROUND AND AIMS OF THE STUDY

The benefits of transesophageal echocardiography (TEE) may depend on the clinical likelihood of infective endocarditis, but little data exist on patients at low risk.

METHODS AND RESULTS

We studied 32 patients with renal failure with either a low (n = 21) or high (n = 11) level of clinical suspicion for infective endocarditis. In the low-risk cases, TEE provided no new information whether the transthoracic echo was normal or abnormal, although it did confirm that an echogenic mass was more likely to be a calcific deposit than a vegetation. In the high-risk cases, transthoracic echocardiography was always abnormal but TEE added new information in seven out of 11 cases-positively in six, and by exclusion in one. TEE detected signs of complications of infective endocarditis in one case.

CONCLUSIONS

We conclude that, when the clinical suspicion of endocarditis is low, TEE is rarely necessary.

Expression of capsules by Haemophilus influenzae in mixed infections

The pathogenicity of eight clinical isolates of non-type b Haemophilus influenzae was investigated by inoculating them subcutaneously into mice, alone or mixed with viable or non-viable bacteria of certain other species. Three of the H. influenzae isolates were non-capsulated while five were slightly capsulated (less than 1% of organisms had capsules). The other strains of bacteria tested were four isolates of capsulated and four isolates of non-capsulated pigmented strains of Prevotella sp. and Porphyromonus sp. as well as a capsulate Klebsiella pneumoniae ("helpers"). None of the non-capsulated strains induced an abscess when inoculated alone. Following co-inoculation of viable or non-viable "helpers" with H. influenzae, abscesses were formed in all instances in which the "helper" had a capsule. Profusely capsulated cells of H. influenzae were recovered, however, only from abscesses induced with the five slightly capsulated strains of H. influenzae. These capsulated organisms were found serologically to be of type b and induced abscesses when inoculated alone. Our findings illustrate the ability of non-capsulated strains of H. influenzae to produce progeny of capsulated type b organisms after co-inoculation with certain other species.

Increased resistance of encapsulated Bacteroides fragilis to clindamycin

The antimicrobial susceptibility and in vitro growth curve of 4 nonencapsulated and 4 encapsulated isolates of Bacteroides fragilis were determined for clindamycin. The MIC of the nonencapsulated isolates was 1-2 dilutions less (0.062-0.25 microgram/ml) than the MIC for their encapsulated counterparts (0.25-0.5 microgram/ml). No difference was noted in the bacterial growth of the nonencapsulated or encapsulated isolates when incubated without clindamycin. The decline in the number of nonencapsulated isolates was significantly lower (p < 0.05) as compared to the encapsulated isolates when incubated with 0.1 or 0.4 microgram/ml of clindamycin. These results illustrate the higher susceptibility of nonencapsulated B. fragilis isolates to clindamycin as compared to their encapsulated counterparts. Since B. fragilis becomes more encapsulated during the infectious process, this finding underscores the advantage of early antimicrobial prophylaxis and therapy.

In-vitro susceptibility and in-vivo efficacy of antimicrobials in the treatment of intraabdominal sepsis in mice

Cefoxitin, cefotetan, cefmetazole, ceftizoxime, imipenem plus cilastatin, ampicillin plus sulbactam and clindamycin alone or combined with gentamicin, ciprofloxacin, ofloxacin or aztreonam were compared in the therapy of intraabdominal infection in mice caused by Escherichia coli in combination with either Bacteroides fragilis or Bacteroides thetaiotaomicron. Mortality in the control group was 45%, and no animal receiving either imipenem, gentamicin, ciprofloxacin, ofloxacin or aztreonam died. Mortality in mice receiving cefoxitin, cefotetan, cefmetazole, or ceftizoxime was below 7% (P < 0.05%) and mortality following treatment with ampicillin-sulbactam was 23-27% (P > 0.05). The abscesses were examined ten days after inoculation. No abscesses were observed in mice treated with clindamycin or imipenem. Therapy with gentamicin, ciprofloxacin, ofloxacin, aztreonam or ceftizoxime alone did not prevent abscess formation by both Bacteroides sp. A significant reduction in abscess formation and number of E. coli and B. fragilis was observed with combination therapy of clindamycin with either ciprofloxacin, ofloxacin, aztreonam, or gentamicin and single agent therapy with either imipenem, cefoxitin, cefotetan, cefmetazole and ampicillin-sulbactam alone. However, cefotetan and cefmetazole did not reduce abscess formation or the number of B. thetaiotaomicron. These in-vivo data confirm the in-vitro activity of these antimicrobials.

Pathogenicity of encapsulated Bacteroides melaninogenicus group, B. oralis and B. ruminicola subsp. brevis in abscesses in mice

The pathogenicity of 27 clinical isolates of the Bacteroides melaninogenicus (BM) group and four clinical isolates of B. oralis and B. ruminicola subsp. brevis were investigated by inoculating them into mice and subsequently determining their ability to cause subcutaneous (SC) or intraperitoneal abscesses. Only 11 isolates of BM group and one B. ruminicola induced abscesses in mice, and all were found to be heavily encapsulated on recovery from the abscesses (more than 50 per cent of the organisms were encapsulated). When the other 23 isolates, however, were injected SC in combination with either Klebsiella pneumoniae, Haemophilus influenzae, Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus or Streptococcus pyogenes, abscesses were formed in 16 of the 23 combinations. The Bacteroides spp. recovered from the mixed infection were heavily encapsulated. Capsules also formed in Bacteroides if the organisms were injected together with capsular material or formalin killed cells of K. pneumoniae or encapsulated Bacteroides sp. Once non-encapsulated or only slightly encapsulated strains acquired a capsule, they could induce abscesses on reinoculation into mice.

Experimental mandibular osteomyelitis: therapeutic trials with hyperbaric oxygen

Hyperbaric oxygen (HBO) has been reported to be beneficial in the treatment of mandibular osteomyelitis; however, controlled laboratory studies have been limited to the long bones. In this study, osteomyelitis was created in surgically fractured rabbit mandibles by inoculation of Bacteroides melaninogenicus. Two months after inoculation, osteomyelitis was verified by bacterial cultures and inspection of the fracture sites. The animals were then randomly divided into treatment and control groups. The treatment group received HBO (2 atmospheres) for two hours daily for 40 treatment days, whereas the control group was maintained on ambient air. Although HBO therapy did not eliminate the chronic osteomyelitis, it did result in a significant improvement in sinus tract healing, osseous repair, and diminished mobility at the fracture site.

Identification, distribution, and toxigenicity of obligate anaerobes in polluted waters

A seasonal occurrence of obligately anaerobic bacteria, predominantly of the genera Bacteroides and Clostridium, in a polluted water site has been observed. The number of anaerobes varied from 1.8 X 10(3) cells/ml in the warmer months to 10 cells/ml in winter. Several isolates were toxigenic, indicating a potential human health hazard.

Alterations in mouse fecal flora associated with hyperbaric stress

The effect of hyperbaric stress on the composition of fecal microflora was investigated in the mouse. Mice were exposed to 35 ATA with normoxic PO2 concentration in a helium atmosphere at 35 degrees C to prevent body heat loss or to 1 ATA oxygen-helium at 25 degrees C. Freshly discharged fecal pellets were cultured under strict anaerobic conditions, replica plated, and then cultured both aerobically and anaerobically. From experiment to experiment there was considerable variation in the total number of cultured bacteria. By replica plating, however, a consistent reduction in the relative numbers of obligate anaerobes was demonstrated, from a mean of 71% to 44%, in the pressurized mice. Bacteroids distasonis and B. multiacidus were the obligately anaerobic species most frequent identified from mice exposed at 35 and 1 ATA. Major changes in species distribution were not encountered.

Evidence of bacteremia and endotoxemia in mice undergoing hyperbaric stress

Swiss albino mice were exposed to normoxic (PO2 approximately 0.2 ATA) helium at 1, 20 or 35 ATA for 2 or 48 h and examined for the presence of bacteria and endotoxin in selected tissues. Among mice exposed to 35 ATA for 48 h and tested immediately after decompression for bacteria in liver and peritoneal cavities, 6 of 30 (20%) contained gram-negative rods and 27 of 30 (90%) contained gram-positive cocci. Incidence of infection was considerably less in mice exposed to 35 ATA for 2 h or exposed to 1 ATA. Evidence of presence of gram-negative rods and /or escape of free endotoxin from the intestine was provided by demonstration that limulus lysate is coagulated (presumptive evidence of endotoxin) by liver homogenates in 70% of the mice exposed to 35 ATA for 48 h, 68% of those exposed to 20 ATA and 14% of those exposed to 1 ATA. Mice subjected to the hyperbaric stress of 35 ATA for 48 h were shown to be increasingly susceptible to injection with purified lipopolysaccharide. The LD50 was 0.24 mg for hyperbaric exposed mice and 0.39 mg for the control groups. These data suggest that hyperbaric stress, but not necessarily decompression, results in a short-term presence in mouse tissues of microbial agents originating from the gut. This invasion temporarily renders that host more susceptible to additional endotoxic challenge.

Effect of exposure to hyperoxic, hypobaric, and hyperbaric environments on concentrations of selected and aerobic and anaerobic fecal flora of mice

Alterations in selected aerobic and anaerobic fecal microflora of the mouse were determined during exposure to hyperoxic and normoxic hypo- and hyperbaric environments. Examination of fecal cultures obtained during exposure for 6 weeks to either 60 or 77% oxygen concentration 1 atmosphere absolute revealed little alteration in the aerobic or anaerobic flora. There appeared to be only a retardation in the reduction of the Klebsiella-Enterobacter flora which normally occurs after weaning. During exposure to hypobaric environments (100% O-2, 0.2 atmosphere absolute), significant alterations in concentrations of Escherichia coli, slow lactose fermenters, Klebsiella-Enterobacter, and enterococci were found in some instances. All alterations were toward increased concentrations. Variations in concentrations of different colony types of obligately anaerobic gram-positive (anGPR) and gram-negative (anGNR) rods cultured during the same experiments also occurred. One colony type of anGPR appeared to decrease while a second type increased in numbers. Concentrations of three colony types of anGNR were generally, but not always, increased. During hyperbaric exposure (2.8% O-2, 7.5 atmospheres absolute), increased concentrations of Klebsiella-Enterobacter, E. coli, slow lactose fermenters and enterococci were also noted. Changes in numbers of both colony types of anGPR, when occurring, were in the direction of lower numbers. Alteration in numbers of anGNR were in both directions but were more frequent in the direction of higher numbers. After return to normal air for 4 weeks of either hypo- or hyperbaric exposure, fecal concentrations of all organisms tended to revert toward control values with the exception of the anGPR which remained in lower concentrations after termination of the hyperbaric exposure. These observations indicate that, despite the great variation in the fecal flora among individual mice, it is possible to discover the effects induced by altered gaseous environments.

Effect of Interferon and Interferon Inducers on Infections with a Nonviral Intracellular Microorganism, Chlamydia trachomatis

The effect of mouse interferon (IF) on the multiplication of Chlamydia trachomatis (strain MRC-1/G) in homologous (L-929) cell cultures and the effect of the IF inducers Newcastle disease virus (NDV) and polyriboinosinic acid-polyribocytidylic acid complex (poly I:C) on the experimental infection of mice with aerosolized C. trachomatis (strain MoPn) were investigated. Treatment of infected cell cultures with IF reduced the number of cells containing chlamydial inclusions and depressed the yield of chlamydiae as determined by titrations for infectivity. Growth of chlamydiae was reduced when cultures were exposed to IF 6 or 18 hr before infection, and slight reduction of the yield was also detectable in cell cultures treated with IF at early intervals (0 or 4 hr) after chlamydial infection. No effect of IF on penetration of chlamydiae into mouse cells was observed, whether phagocytic cells from peritoneal washings or L-929 cells were used, indicating that the inhibitory effect of IF occurs after chlamydiae enter the host cell. Additional evidence was obtained that a significant effect of IF occurs at an early stage in maturation of the intracellular chlamydiae. In mice exposed repeatedly to NDV aerosols and challenged with aerosolized MoPn 8 hr after the first exposure to NDV, mortality was delayed by 2 to 3 days and lung consolidation was slightly reduced at 3 days after infection. Yields of chlamydiae from lung pools of NDV-treated mice, taken at 3, 6, and 9 days after challenge, were not significantly different from those of controls. Similar results were obtained when mice were challenged with MoPn 8 hr after intranasal injection with 100 μg of poly I:C or 24 hr after intravenous injection with 200 μg of poly I:C. In contrast, administration of 0.2 ml of NDV (10 8.3 plaque-forming units) intravenously 10 hr before or 24 hr after challenge with MoPn accelerated mortality of mice by 2 to 3 days. In all experiments, detectable levels of IF in sera or 20% lung suspensions were found only up to 48 to 72 hr after exposure of mice to IF inducers.

Bacteriological studies on trachomatous and normal persons from three areas on Taiwan

A series of eye cultures was obtained in 1961 in three areas on Taiwan from both normal and trachomatous children. About one-half of the cultures were from clinical cases classified as being in one of the various trachomatous stages. The other half were from cases of normal or simple conjunctivitis. Total isolation rates were 36.6% for the trachoma group and 35.2% for the control group. If chronic follicular conjunctivitis and simple conjunctivitis cases were disregarded, that did not affect the ratio of isolations between the two groups. As the temperature and humidity increased from February through May 1961, the percentage of positive isolations increased. It is shown that bacterial conjunctivitis had less than a 1% effect on the clinical manifestation of trachoma on Taiwan and that it was equal between the trachoma and control groups.