Reconstitution of T-cell repertoire after autologous stem cell transplantation: influence of CD34 selection and cytomegalovirus infection.

The period of immunodeficiency following autologous hematopoietic stem cell transplantation is characterized by transient expansions of CD8+CD45RO+CD57+ T lymphocytes, displaying markers of an activated phenotype. Most evidence suggests that this early reconstitution results from proliferation of mature T cells that have survived conditioning or were transferred with the graft. Although homeostatic mechanisms are thought to act in maintaining total T-cell numbers, the degree to which antigen-driven expansions contribute and the nature of the stimulating antigens remain unclear. CD34 selection of stem cell grafts reduces the available T-cell pool, potentially delaying immune reconstitution and resulting in increased infective complications. In the allogeneic transplantation setting, lymphopenia has been associated with cytomegalovirus (CMV) infection risk and, if persistent, with adverse outcome. We prospectively studied patients undergoing CD34-selected (n = 13) or unselected (n = 13) autologous hematopoeitic stem cell transplantation for immune reconstitution and CMV infection. No significant differences were demonstrated between graft types with respect to lymphocyte subset recovery, T-cell receptor beta-chain variable region spectratype diversity, or CMV DNA detection rates (45% versus 40%). CMV infection was associated with a trend toward higher rather than lower CD8+ counts at 6 weeks posttransplantation (P =.08) that became significant by 3 months (P=.007), and that was associated with decreased T-cell receptor beta-chain variable region spectratype diversity (P =.01). CMV-specific HLA-tetramer analysis demonstrated transient expansions with CDR3 lengths corresponding to those of some of the major posttransplantation T-cell expansions demonstrated by spectratype analysis suggesting that CMV-specific T cells contribute to the pattern of immune reconstitution.     

Analysis of mycolic acid cleavage products and cellular fatty acids of Mycobacterium species by capillary gas chromatography.

After growth and experimental conditions were established, the mycolic acid cleavage products, constituent fatty acids, and alcohols of representative strains of Mycobacterium tuberculosis, M. smegmatis, M. fortuitum complex, M. kansasii, M. gordonae, and M. avium complex were determined by capillary gas chromatography. Reproducible cleavage of mycolic acid methyl esters to tetracosanoic (24:0) or hexacosanoic (26:0) acid methyl esters was achieved by heating the sample in a high-temperature muffle furnace. The major constituent fatty acids in all species were hexadecanoic (16:0) and octadecenoic (18:1 omega 9-c, oleic) acids. With the exception of M. gordonae, 10-methyloctadecanoic acid was found in all species; moreover, M. gordonae was the only species tested which contained 2-methyltetradecanoic acid. M. kansasii was characterized by the presence of 2,4-dimethyltetradecanoic acid, M. avium complex by 2-eicosanol, and M. tuberculosis by 26:0 mycolic acid cleavage product. The mycolic acid cleavage product in the other five species tested was 24:0. Although a limited number of strains and species were tested, preliminary results indicate that this gas chromatographic method can be used to characterize mycobacterial cultures by their mycolic acid cleavage products and constituent fatty acid and alcohol content.     

Cellular fatty acids of Capnocytophaga species.

The cellular fatty acid composition of 18 clinical isolates and 4 reference strains of Capnocytophaga species (Capnocytophaga ochracea, Capnocytophaga gingivalis, and Capnocytophaga sputigena) was determined by gas-liquid chromatography. The fatty acid profiles of the 22 cultures were essentially identical and were characterized by major amounts (60% or greater) of a saturated, iso-branched-chain, 15-carbon acid (13-methyl-tetradecanoate) and the presence of two relatively uncommon saturated, iso-branched, 3-hydroxy acids (13-methyl-3-hydroxy-tetradecanoate and 15-methyl-3-hydroxy-hexadecanoate). The presence and relative amounts of these acids distinguish Capnocytophaga spp. from other gliding bacteria.     

The effect of calcium on the maximum velocity of shortening in skinned skeletal muscle fibres of the rabbit

Summary The relationship between maximum shortening velocity (V _max) and free calcium concentration has been studied in skinned single fibres from rabbit psoas and soleus muscles. At both 10 and 15° C,V _max measured in the psoas fibres was found to decrease by 40% when the pCa (-log[Ca²⁺]) was increased from 5.49 (maximally activating) to 6.21. Further decreases inV _max were observed when the pCa was increased to 6.32.V _max measured in soleus fibres at 15° C also decreased when the Ca²⁺ concentration was lowered, though the magnitude of this effect was slightly less than in the psoas fibres. Thus, a distinct effect of Ca²⁺ uponV _max has been shown to occur in mammalian skeletal muscle. The occurrence of this effect in both fast and slow muscle types may indicate that the underlying mechanism in the two cases is similar.     

Fos-like immunoreactivity in brain regions of domestic rams following exposure to rams or ewes

Limbic and basal forebrain-hypothalamic regions from male sheep differing in sexual performance were quantified for fos-like immunoreactivity. Rams classified as high-sexually performing (HP), low-sexually performing (LP), and male-oriented (MO) received noncontact sensory stimulation from either ewes in estrus (HP, n=5; LP, n=4; MO, n=4) or other males (HP, n=5; LP, n=4; MO, n=5) for a 4-h period on each of 3 consecutive days. Following exposure to stimulus animals on the third day, rams were euthanized and their brains were perfused with a 1% paraformaldehyde/1.5% glutaraldehyde solution and sections were analyzed for fos-like immunoreactivity. Brain regions analyzed were the medial amygdala (meAMY), medial preoptic area (mPOA), bed nucleus of the stria terminalis (BNST), and ventromedial hypothalamic nucleus (VMH). Fos-like immunoreactivity differed between groups in the mPOA and BNST but not in the meAMY or VMH. LP rams exposed to estrous ewes had more (P<.05) neurons staining positive for fos and fos-related antigens (FRA) in the mPOA and BNST than LP rams exposed to other rams or MO rams exposed to either estrous ewes or other rams. Numbers of neurons staining positive for FRA in the mPOA and BNST of LP rams exposed to estrous ewes, however, were not different (P>.05) from HP rams exposed to either estrous ewes or other rams. The similar fos-like immunoreactivity in areas important for the display of sexual behavior in HP and LP rams may reflect similar sensory input in these two groups of rams; however, LP rams, in contrast to HP rams, do not appear to respond similarly to the same sensory stimulus.     

Cutaneous malignant melanoma in the young

Cutaneous malignant melanoma in children and adolescents is rare. Of over 1600 patients documented in the Melanoma Registry at Frenchay Hospital from 1967 onwards, only 29 cases are recorded who were 21 years of age or younger. Of these, four patients were pre-pubertal (13 years or less) and none arose from a congenital "giant" naevus. Fifteen patients developed metastases, 10 of whom showed spread of tumour within 30 months of initial presentation. Eight of these patients with metastatic disease died, with a maximum survival of 61 months. Only seven patients, five of whom have metastatic disease, survive more than 10 years after first presentation; nine patients, one of whom has secondaries, survive for 5 years or less.     

Biological Activity of Sch 14342, an Aminoglycoside Antibiotic Coproduced in the Gentamicin Fermentation

Sch 14342 is an aminoglycoside antibiotic coproduced as a minor component in the gentamicin fermentation. Sch 14342 was found to have the same antibacterial spectrum as gentamicin in vitro and in vivo, and was approximately one-third as active in mouse protection tests. Sch 14342 relative to gentamicin was one-third as toxic in acute tests in mice, one-eighth as toxic in renal toxicity tests in dogs, and an estimated one-tenth as toxic in cat ataxia tests. Sch 14342 possesses a significantly improved therapeutic index relative to gentamicin with reference to ataxia potential and renal toxicity.     

Phenotypic characterization, cellular fatty acid composition, and DNA relatedness of aerococci and comparison to related genera.

Aerococci can be misidentified as streptococci, enterococci, pediococci, lactococci, or leuconostocs. To distinguish the genus and determine if another species is needed in the present taxon, we analyzed 37 aerococci for cellular fatty acids and compared them with 377 strains of gram-positive cocci, including the species type strains from each of the related genera. The cellular fatty acid profile of aerococci was distinguishable from other genera. Two relatively novel fatty acids found in the aerococci were identified as C16:1 omega 9c and C16:1 omega 9t. Eleven strains of aerococci (including a strain originally identified as "Gaffkya" species) were chosen for DNA-DNA reassociation studies with the type strain Aerococcus viridans ATCC 11563; DNAs from eight of these strains were more than 75% related to the type strain and had 1 to 4% divergence in related sequences. The remaining three strains were 60 to 70% related to the type strain, had 7 to 11.5% divergence, and may represent a second species, Aerococcus genospecies 2. beta-Glucuronidase, alpha-galactosidase, and beta-galactosidase were useful in characterizing the aerococci.     

Sexual functioning of male anabolic steroid abusers

The effects of anabolic steroid use on male sexual behavior were assessed using a structured clinical interview administered to male body builders currently using steroids, and to two comparison groups (body builders with a past but not current history of steroid use, and a group of natural body builders who had never used steroids). Current anabolic steroid users had a significantly higher coital and orgasmic frequency than did comparison athletes. They also reported a significantly higher incidence of erectile difficulties during the past month. Beliefs concerning the sexually stimulating effects of steroids did not correlate with the frequencies of specific sexual behaviors. The data support the contention that anabolic steroids, as androgenic compounds, enhance sexual desire.