High levels of photosystem I subunit II (PsaD) mRNA result in the accumulation of the PsaD polypeptide only in the presence of light

The light-regulated mRNA and polypeptide accumulation of the nuclear encoded subunit II (PsaD) of the photosystem I reaction center was studied during the greening of etiolated spinach seedlings. Upon exposure to continuous white light, the mRNA, detected at low levels in etiolated seedlings, accumulated in a specific pattern. In contrast, the PsaD subunit could not be detected in the etiolated seedlings; the polypeptide could first be detected in thylakoid membranes approximately 4 h after exposure to continuous light. A pulse of red light induced the expression of the PsaD mRNA, but the polypeptide could not be detected unless the seedlings were exposed to light. In the light (but not in the dark), the PsaD mRNA was found associated with the polysomal fraction. Taken together, the data suggest a dual regulatory mechanism in which both the level of mRNA and the presence of light control the accumulation of the PsaD polypeptide.

[Primary breast lymphoma]

A 66-year-old woman with a previous diagnosis of benign histiocytosis of the right breast developed intermediate grade malignant lymphoma of her left breast 6 years later. It is suggested that the primary disease was actually a low-grade lymphoma of the MALT subgroup (mucosa-associated lymphoid tumors) which 6 years later had undergone transformation into high-grade lymphoma. This assumption is based on the known histological similarity between MALT lymphomas and benign histiocytosis.

Nonmagnetic hyperbaric chamber for in vivo NMR spectroscopy studies of small animals

A description is given of the design, construction, and initial use of a polycarbonate resin hyperbaric chamber for in vivo NMR spectroscopy studies of anesthetized, ventilated rats in a horizontal bore 4.7 Tesla magnet. The chamber and its associated equipment, initially used for hyperbaric studies of rats in states of extreme hypercapnia, are also well suited for conventional hyperbaric studies, such as those related to hyperbaric oxygen therapy, oxygen toxicity, and diving. Basic technical challenges that required innovations involved: a) preservation of magnetic field homogeneity; b) avoidance of a metallic chamber body that would overload gradient and RF coils; c) physiological monitoring; and, d) remote control and stabilization of electromagnetic and physiologic factors (especially ventilatory stability) during pressure changes. A small paramagnetic bulk magnetic susceptibility shift from chamber-associated hyperbaric oxygen was observed when chamber oxygen tensions were only one atmosphere. High-quality NMR imaging and spectroscopy were demonstrated during hyperbaric conditions.

[Tension pneumothorax from inappropriate oxygen administration]

Hospital oxygen delivery systems provide pressures of 50-55 PSI (about 4000 cm H2O). Inappropriate administration can result in severe barotrauma. Administration of O2 by face mask in an intubated patient resulted in an inadvertent connection between the oxygen and endotracheal tubes, which caused tension pneumothorax with cardiorespiratory collapse. As several such cases have been reported, we believe O2 should be administered to intubated patients only through a T-piece connection. We call for a change in the structure of O2 delivery tubes to prevent the possibility of inadvertent connection to an endotracheal tube.

Efficacy of granulocyte colony-stimulating factor and RU-40555 in combination with clarithromycin against Mycobacterium avium complex infection in C57BL/6 mice

We compared the activities of two different biological-response modifiers with that of clarithromycin against Mycobacterium avium complex infection in C57BL/6 mice. Mice were pretreated daily with clarithromycin (50 mg/kg of body weight subcutaneously [s.c.]), RU-40555 (100 mg/kg s.c.), or granulocyte colony-stimulating factor (G-CSF) at low dose (15 micrograms/kg intraperitoneally [i.p.]) or high dose (300 micrograms/kg i.p.) 3 days before intravenous challenge with 2.5 x 10(7) CFU of the MO-1 strain of M. avium complex. Mice were treated daily until sacrifice at day 1, 8, 15, or 21 after challenge, and the numbers of CFU were measured per gram of tissue in lung and spleen. Compared at day 21 with control treatment, clarithromycin significantly decreased the level of infection in spleen (P < 0.0001) and lungs (P < 0.0001). Compared with control treatment, G-CSF at low dose had no activity, but G-CSF in combination with clarithromycin was more effective than clarithromycin alone in spleen (P < 0.05) and lungs (P < 0.015). The high dose of G-CSF was as effective as the low dose. RU-40555 alone had no beneficial activity. The RU-40555-clarithromycin combination was more effective than control treatment in spleen (P = 0.0001) and lungs (P < 0.0005) and more effective than clarithromycin alone in spleen (P < 0.009) but not in lungs. Thus, our experiments suggest that clarithromycin alone or in combination with G-CSF should be further evaluated for the prophylaxis of M. avium complex infection.

[Biclonal gammopathies: clinical and theoretical aspects]

Monoclonal gammopathies are disorders in which a clone of lymphocytes arising from a common ancestor cell proliferates and secretes a monoclonal antibody. Electrophoresis of plasma proteins is used as a diagnostic test for these disorders. It produces a narrow peak within the zone of gammaglobulins, corresponding to the monoclonal antibody. On rare occasions electrophoresis produces 2 narrow peaks simultaneously, suggesting the existence of 2 monoclonal antibodies, establishing a biclonal gammopathy. We present 4 such patients with biclonal gammopathy. The prevalence of mono- and biclonal gammopathies in the general population ranges between 1-3%, but only 1% of these are biclonal. Patients with biclonal gammopathy do not differ clinically from those with monoclonal gammopathy. Theoretically, pathogenesis of biclonal gammopathies might involve true biclonicity: 2 separate transformations in 2 precursor cells. Alternatively, the 2 transformed clones might have originated from a common ancestor cell early in differentiation, prior to immunoglobulin gene rearrangement; in this case pseudobiclonicity could be implied. The question of true biclonicity versus pseudobiclonicity has been examined by others using statistical analysis of isotypic combination distributions of heavy and light chains. The incidence of identity of the light chain isotype in both monoclonal antibodies (44%) was higher than would be expected in a random distribution (27%). In a study of the 2 monoclonal immunoglobulins, the identity of the amino acid sequences of the variable site was demonstrated, suggesting a common ancestor. In another research, anti-idiotypic antibodies suggested a common idiotype in the 2 proteins. Immunofluorescent labeling of bone marrow cells produced conflicting evidence of biclonicity in several studies.(ABSTRACT TRUNCATED AT 250 WORDS)

[Update of experience with prostatic cancer]

A retrospective analysis of 302 patients with prostatic cancer, referred between 1977-1982, was updated. 15 patients (5%) with Stage A1 disease did not receive any specific treatment, and their 10-year actuarial survival was 77%. 22 (7%) had Stage A2 disease at diagnosis, 82 (27%) Stage B, 88 (29%) Stage C, and 95 (32%) Stage D. Their 10-year actuarial survival rates were 75%, 56%, 38%, and 2%, respectively. The 10-year actuarial survival of patients with well- and moderately well-differentiated adenocarcinoma was 61%, but only 13% in those with poorly differentiated adenocarcinoma (p < 0.001). A total of 116 patients with Stages A2, B and C were treated by irradiation and 71 of them also received prophylactic hormone therapy. The 10-year actuarial survival of those treated by combined irradiation and hormone therapy was 59%, compared to 19% for those treated by irradiation alone (p < 0.02). Our results emphasize the need for early diagnosis of prostatic cancer, using modern diagnostic tools such as transrectal ultrasonography and determination of prostatic specific antigen. They also prove that radiotherapy is effective and curative in a high percentage of patients with disease confined to the pelvis.

Prospective evaluation of the incidence of bacteremia after protected specimen brushing in ICU patients with and without pneumonia

To test the hypothesis that the use of protected specimen brushing (PSB) via flexible bronchoscopy does not predispose to bacteremia in ICU patients, we prospectively performed aerobic and anaerobic blood cultures immediately following bronchoscopy with PSB. A total of 123 episodes in 68 consecutive patients with suspected pneumonia were analyzed. Blood cultures were negative in 110 cases (89 percent) and positive in 13 cases (11 percent) (p < 0.001). Twelve of these 13 patients with positive blood cultures had quantitative PSB specimen cultures showing nonsignificant growth (< 10(3) CFU/ml). In nine patients, the bacteria recovered from blood cultures (coagulase-negative staphylococci or sarcina) were considered nonpathogenic according to conventional criteria. Blood cultures grew a Staphylococcus aureus in two patients with previously documented staphylococcal septicemia. In one patient with no identifiable site of infection, the blood culture yielded Enterococcus faecalis. The only patient with both a positive blood culture and PSB culture results indicating pneumonia had different organisms recovered from the two samples. Blood cultures taken after PSB in the 17 other episodes of pneumonia (PSB specimen cultures > or = 10(3) CFU/ml) were negative. At the time of brushing and blood sampling for culture, none of these patients was receiving antibiotics active on the organisms found. In conclusion, the incidence of bacteremia after PSB in ICU patients seems very low even in patients with documented pneumonia. Substantial savings would result from not performing routine blood cultures after PSB.

Primary small noncleaved cell lymphoma of the liver. Report of an adult case in complete remission after treatment with combination chemotherapy

Open liver biopsy in a 34-year-old woman with hepatosplenomegaly showed small noncleaved cell lymphoma. Except for an enlarged spleen, there was no evidence of other sites of involvement. She was treated with combination chemotherapy and is alive and free of disease > 5 years after diagnosis. We believe this to be the first reported case in an adult of primary hepatic or hepatosplenic lymphoma of the small cleaved cell type with long-term disease-free survival.

Sparfloxacin, ethambutol, and cortisol receptor inhibitor RU-40 555 treatment for disseminated Mycobacterium avium complex infection of normal C57BL/6 mice

Sparfloxacin (50 mg/kg of body weight given subcutaneously each day), alone or in combination with ethambutol (50 mg/kg given subcutaneously each day), was examined for its therapeutic efficacy against experimental infection induced with the Mycobacterium avium complex in normal C57BL/6 mice. In addition, the potential anti-infective role of RU-40 555 (100 mg/kg given intraperitoneally each day), a drug that inhibits the cortisol receptors, was examined in the same model. Treatments were started 24 h after intravenous bacterial challenge and were continued for 21 days. Compared with controls, sparfloxacin or ethambutol decreased the CFU counts in spleens and lungs (P < 0.001). The sparfloxacin plus ethambutol combination was more effective than sparfloxacin alone in spleens (P < 0.001) but not in lungs. The sparfloxacin plus ethambutol plus RU-40 555 combination was more effective than the sparfloxacin plus ethambutol combination in spleens and lungs (P < 0.001). Thus, in this model, RU-40 555 enhanced the antibacterial activities of the antibiotics tested. Results of the study showed that normal C57BL/6 mice infected with the M. avium complex can be used for the evaluation of antimicrobial agents.

Activities of WIN-57273, minocycline, clarithromycin, and 14-hydroxy-clarithromycin against Mycobacterium avium complex in human macrophages

The activities of the fluoroquinolone WIN-57273, 14-OH clarithromycin (a human metabolite of clarithromycin), and minocycline against two virulent strains of Mycobacterium avium complex were evaluated in a model of intracellular infection and compared with that of clarithromycin. Human monocyte-derived macrophages were infected at day 6 of culture. Intracellular CFU at 60 min and intracellular and supernatant CFU on days 4 and 7 were counted after inoculation. The concentrations used, which were equal to peak levels in serum, were 3 micrograms of WIN-57273 per ml (MICs for the two strains, 1 microgram/ml), 4 microgram of 14-OH clarithromycin per ml (MICs, 8 and 2 micrograms/ml, respectively, at pH 7.4), 4 micrograms of minocycline per ml (MICs, 64 and 32 micrograms/ml, respectively), and 4 micrograms of clarithromycin per ml (MICs, 2 and 0.5 micrograms/ml, respectively, at pH 7.4). On day 7, compared with controls, WIN-57273, minocycline (P less than 0.02), clarithromycin, or different combinations of clarithromycin and the other drugs (P less than 0.001) slowed the intracellular replication of strain MO-1. 14-OH clarithromycin (P less than 0.02), clarithromycin (P less than 0.02), 14-OH clarithromycin plus clarithromycin (P less than 0.01), clarithromycin plus minocycline, or clarithromycin plus minocycline plus 14-OH clarithromycin (P less than 0.001) slowed the intracellular replication of strain LV-2. WIN-57273 was less effective than clarithromycin against strain MO-1 (P less than 0.05). Clarithromycin plus 14-OH clarithromycin plus minocycline (P less than 0.02) was more effective than clarithromycin alone against strain LV-2. Thus, clarithromycin plus minocycline, which corresponds in humans to three active molecules, may exhibit a better efficacy than clarithromycin in this model.

Striatal dopamine metabolism is differentially affected by insulin according to the genotype in Zucker rats: a microdialysis study

The genetically obese Zucker rat presents several abnormalities related to insulin and brain monoamines, which may play a role in its impaired regulation of food intake and body weight. In a previous study, the possible insulin-monoamine interplay was investigated by measuring brain monoamine and metabolite levels in the three genotypes of the Zucker strain. In addition to the expected results, insulin had a particular effect on striatal dopamine (DA) release, regardless of ponderal status and genotype. We further investigated this point in the present study, using the brain microdialysis technique in the striatum. Lean homozygous Fa-Fa rats responded as expected to insulin with regard to striatal DA release, with increases in DA and 3-methoxy-tyramine levels and decreases in dihydroxyphenylacetic acid and homovanillic acid. Lean heterozygous Fa-fa rats showed a very specific response profile, with decreases in all dopaminergic parameters, suggestive of an effect on DA synthesis rather than DA release. This further emphasizes the marked differences between homozygous and heterozygous lean rats. The obese fa-fa rats clearly fell into two populations. The first showed a profile of response to insulin similar to that of the lean Fa-fa rats, in keeping with the disturbances related to the "fa" gene. The second showed an increase in all the dopaminergic parameters. This pattern of response was, however, different from that of the Fa-Fa rats. These opposing responses in the two obese populations did not reflect differences in the blood glucose response to insulin. One explanation is that 16 wk may be a critical transition period in the development of genetic obesity, with regard to brain monoamine disturbances and the response to insulin.

Primary brain lymphoma after X-ray irradiation to the scalp for tinea capitis in childhood

A 39-year-old male developed primary brain lymphoma 33 years after receiving scalp irradiation for tinea capitis. This is the first reported association between cranial irradiation during childhood and subsequent development of primary brain lymphoma.