Dietary zinc intake and sex differences in taste acuity in healthy young adults

BACKGROUND

Previous research suggests that adequate dietary zinc intake may be important in determining the sensory experience of food, appetite and consequently, dietary quality. The aim of this pilot study was to explore relationships between taste sensitivity and dietary zinc intake in healthy young adults (age 20-40 years: 24 male, mean age +/- SD = 27 +/- 4.86 years; 26 female, mean age +/- SD = 23 +/- 2.10).

METHOD

A signal detection method was used to assess taste acuity for the four basic tastes: sweet (glucose), sour (citric acid), salt (sodium chloride) and bitter (quinine). A 4-day food diary was used to determine dietary intakes of zinc (mg day(-1)) and salt.

RESULTS

Males reported a higher zinc intake than females (P=0.001). Higher dietary zinc intake was associated with better taste acuity for salt in females (P=0.017) but not in males. Acuity for bitter taste appeared to be related to zinc intake in males (P=0.007) but not females. Among those whose average daily zinc intake was below the RNI, males were less sensitive than females to sour (P=0.02) and bitter (P=0.014) taste.

CONCLUSION

These findings suggest that zinc is more important for taste acuity in males than females and indicate the importance of taking sex differences into account when studying taste acuity.

Mapping a new genetic locus for X linked retinitis pigmentosa to Xq28

We have defined a new genetic locus for an X linked form of retinitis pigmentosa (RP) on chromosome Xq28. We examined 15 members of a family in which RP appeared to be transmitted in an X linked manner. Ocular examinations were performed, and fundus photographs and electroretinograms were obtained for selected patients. Blood samples were obtained from all patients and an additional seven family members who were not given examinations. Visual acuity in four affected individuals ranged from 20/40 to 20/80+. Patients described the onset of night blindness and colour vision defects in the second decade of life, with the earliest at 13 years of age. Examined affected individuals had constricted visual fields and retinal findings compatible with RP. Based on full field electroretinography, cone function was more severely reduced than rod function. Female carriers had no ocular signs or symptoms and slightly reduced cone electroretinographic responses. Affected and non-affected family members were genotyped for 20 polymorphic markers on the X-chromosome spaced at 10 cM intervals. Genotyping data were analysed using GeneMapper software. Genotyping and linkage analyses identified significant linkage to markers DXS8061, DXS1073, and DXS1108 with two point LOD scores of 2.06, 2.17, and 2.20, respectively. Haplotype analysis revealed segregation of the disease phenotype with markers at Xq28.

Diagnosis of angiomyolipoma using computed tomography—region of interest ≤−10HU or 4 adjacent pixels ≤−10HU are recommended as the diagnostic thresholds

AIM

To study and compare the diagnostic accuracy of region of interest (ROI) density measurement and pixel mapping [computed tomography (CT) density of individual pixels] for the diagnosis of renal angiomyolipoma (AML) using CT.

MATERIALS AND METHODS

A study group of histologically proven AMLs was compared with a control group of histologically proven renal cell cancers, normal renal parenchyma, and simple renal cysts. The mean tissue density (ROI circle) and a pixel density map were recorded. The diagnostic accuracy of various thresholds of ROI and pixel mapping values were compared using receiver operating characteristic curves.

RESULTS

Twenty-two AMLs, 16 renal cell carcinomas (RCCs), 30 simple cysts, and 30 sites of renal parenchyma were evaluated. The mean (+/-1 SD) density of the AMLs was significantly lower [-15.2(20.8) units] than the three control groups [+36.0(8.1) units, +5.4(3.4) units and +22.2(46.5) units for RCC, renal cyst and parenchyma respectively; p < 0.001 (analysis of variance)]. The sensitivities and specificities of the ROI diagnostic thresholds of < or =0 units, < or =-10 units and < or =-20 units were 77 and 97%, 73 and 100% and 50 and 100%, respectively. Using pixel mapping [diagnostic thresholds of either a line of 4 pixels < or =-10 units or a square of 4 pixels < or =-10 units] the sensitivity improves to 86% with a specificity of 97%.

CONCLUSION

Although a ROI threshold value of < or =-10 units has a very high specificity (100% in the present study) the sensitivity is modest at only 73%. Pixel mapping is more sensitive for recognizing small clusters of fat. In practice, both methods can be recommended for the analysis of suspected AMLs. ROI density measurement is convenient when analysing large areas of suspected fat and < or =-10 units should be used as the diagnostic threshold. When faced with small lucent areas or indeterminate values after ROI analysis, pixel mapping is recommended using a line of 4 pixels < or =-10 units or a square of 4 pixels < or =-10 units as the discriminating thresholds.

Tuberose sclerosis complex: analysis of growth rates aids differentiation of renal cell carcinoma from atypical or minimal-fat-containing angiomyolipoma

AIM

To study the radiological characteristics of renal masses in individuals with tuberous sclerosis complex (TSC) using serial CT, and to examine how renal cell carcinoma (RCC) may be differentiated from indeterminate cysts or masses.

METHODS

This was a retrospective study of 12 cases of TSC in which dedicated renal CT followed after US had demonstrated cystic or sonographically unusual renal masses. The CT density of all masses was measured and the masses categorized as simple cysts, complex cysts, angiomyolipomas or indeterminate solid masses. Subjects were maintained on regular follow-up with repeat CT or MRI and interval renal US. Indeterminate masses that showed rapid growth were considered suspicious for renal cell carcinoma and biopsy or nephrectomy followed.

RESULTS

Comparative data were available for a median of 4 years. In each case the renal masses were multiple and bilateral; mean mass diameter was 3.6 cm. Among a total of 206 masses, 18 were simple cysts and 3 were complex cysts. Of the complex cysts, 1 proved to be an angiomyolipoma on histology and the other 2 showed no growth. Of the solid masses, 133 were typical angiomyolipomas (AMLs) and 52 were indeterminate. On follow-up, only 3 indeterminate masses showed rapid growth (>0.5 cm/year), of which only 1 proved to be an RCC on biopsy. The other 2 were minimal-fat AMLs, and the remainder of the masses showed no or slow growth.

CONCLUSION

Many renal masses associated with TSC are radiologically indeterminate. A growth threshold of >0.5 cm/year identified the only RCC in this study (0.5% of all masses). Yearly radiological follow-up of indeterminate renal masses is recommended for individuals with TSC.

Minor H antigens: genes and peptides

In this review, we describe the evidence from which the existence of non-MHC histocompatibility (H) antigens was deduced, the clinical setting of bone marrow transplantation in which they are important targets for T cell responses, and the current understanding of their molecular identity. We list the peptide epitopes, their MHC restriction molecules and the genes encoding them, of the human and murine minor H antigens now identified at the molecular level. Identification of the peptide epitopes allows T cell responses to these antigens following transplantation of MHC-matched, minor H-mismatched tissues to be enumerated using tetramers and elispot assays. This will facilitate analysis of correlations with HVG, GVH and GVL reactions in vivo. The potential to use minor H peptides to modulate in vivo responses to minor H antigens is discussed. Factors controlling immunodominance of T cell responses to one or a few of many potential minor H antigens remain to be elucidated but are important for making predictions of in vivo HVG, GVH and GVL responses and tailoring therapy after HLA-matched BMT and DLI.

The case of the midwife scientist

Genes controlling both testis determining and expression of the male-specific transplantation antigen, HY, are located on the short arm of the mouse Y chromosome, and on the X and Y-linked translocation, Sxr(a). A mutation of Sxr(a) was discovered in a cross between an Sxr carrier male and a T16H/X female. This was designated Sxr(b) and found to affect both the expression of HY and spermatogenesis, but not testis differentiation, thereby disproving Ohno's hypothesis that HY controlled testis determination. Molecular genetic analysis showed the mutation to be caused by fusion of two duplicated genes, Zfy1 and Zfy2, deleting the intervening DNA. This deletion interval, deltaSxr(b), contained a number of genes, each a candidate HY gene. Expression cloning with HY-specific T cell clones identified Smcy, Uty and Dby as encoding peptide epitopes of this transplantation antigen. The human homologues SMCY and UTY likewise express HY antigens and these are targets of damaging graft-versus-host (GVH) responses and potentially therapeutic graft-versus-leukaemia (GVL) responses following bone marrow transplantation (BMT). Knowledge of the peptide identity of HY epitopes allows monitoring of immune responses following BMT, using fluorescent tetramers, and also offers the possibility of inducing immunological tolerance.

Activation of HIV in human skin by ultraviolet B radiation and its inhibition by NFkappaB blocking agents

To determine whether ultraviolet B (UVB) irradiation leads to activation of HIV in human skin, we conducted prospective and controlled studies in two academic medical centers in Texas from July 1995 to April 1999. HIV-positive patients with UV-treatable skin diseases were enrolled at each center, 18 subjects at one and 16 at the other. In one center, specimens from lesional and nonlesional skin biopsies were taken before and after sham- or UVB-irradiation administered in vivo or in vitro. In the other center, UVB phototherapy was administered three times weekly and specimens from skin biopsies were taken before and after 2 weeks (six treatments). Cutaneous HIV load was assessed using reverse transcriptase-polymerase chain reaction and reverse transcriptase-polymerase chain reaction in situ hybridization. UVB irradiation led to a 6-10-fold increase in the number of HIV in skin. To ascertain a role for nuclear factor kappa B (NFkappaB) in UVB-inducible HIV activation, two types of blockers, NFkappaB oligonucleotide decoy and sodium salicylate, were tested; each inhibited UVB-inducible HIV activation in skin partially. We conclude that UVB irradiation leads to increased numbers of HIV in human skin via processes that include release of cytoplasmic NFkappaB.

Nitrogen cycling by wood decomposing soft-rot fungi in the "King Midas tomb," Gordion, Turkey

Archaeological wood in ancient tombs is found usually with extensive degradation, limiting what can be learned about the diet, environment, health, and cultural practices of the tomb builders and occupants. Within Tumulus Midas Mound at Gordion, Turkey, thought to be the tomb of the Phrygian King Midas of the 8th century B.C., we applied a stable nitrogen isotope test to infer the paleodiet of the king and determine the nitrogen sources for the fungal community that decomposed the wooden tomb, cultural objects, and human remains. Here we show through analysis of the coffin, furniture, and wooden tomb structure that the principal degrader, a soft-rot fungus, mobilized the king's highly (15)N-enriched nutrients, values indicative of a diet rich in meat, to decay wood throughout the tomb. It is also evident from the delta(15)N values of the degraded wood that the nitrogen needed for the decay of many of the artifacts in the tomb came from multiple sources, mobilized at potentially different episodes of decay. The redistribution of nutrients by the fungus was restricted by constraints imposed by the cellular structure of the different wood materials that apparently were used intentionally in the construction to minimize decay.

Minor H antigens: genes and peptides

In this review, we describe the evidence from which the existence of non-MHC histocompatibility (H) antigens was deduced, the clinical setting of bone marrow transplantation in which they are important targets for T-cell responses, and the current understanding of their molecular identity. We list the peptide epitopes of the human and murine minor H antigens now identified at the molecular level, their MHC restriction molecules and the genes encoding them. Identification of the peptide epitopes allows T-cell responses to these antigens following transplantation of MHC-matched, minor H-mismatched tissues to be enumerated using tetramers and elispot assays. This will facilitate analysis of correlations with host-versus-graft (HVG), graft-versus-host (GVH) and graft-versus-leukaemia (GVL) reactions in vivo. The potential to use minor H peptides to modulate in vivo responses to minor H antigens is discussed. Factors controlling immunodominance of T-cell responses to one or a few of many potential minor H antigens remain to be elucidated but are important for making predictions of in vivo HVG, GVH and GVL responses and tailoring therapy after HLA-matched bone marrow transplantation and donor lymphocyte infusion.

Examination of HY response: T cell expansion, immunodominance, and cross-priming revealed by HY tetramer analysis

We have applied MHC class I tetramers representing the two H2(b) MHC class I-restricted epitopes of the mouse male-specific minor transplantation Ag, HY, to directly determine the extent of expansion and immunodominance within the CD8+ T cell compartment following exposure to male tissue. Immunization with male bone marrow (BM), spleen, dendritic cells (DCs) and by skin graft led to rapid expansion of both specificities occupying up to >20% of the CD8+ T cell pool. At a high dose, whole BM or spleen were found to be more effective at stimulating the response than BM-derived DCs. In vivo, immunodominance within the responding cell population was only observed following chronic Ag stimulation, whereas epitope immunodominance was established rapidly following in vitro restimulation. Peptide affinity for the restricting MHC molecule was greater for the immunodominant epitope, suggesting that this might be a factor in the emergence of immunodominance. Using tetramers, we were able to directly visualize the cross-primed CD8+ HY response, but we did not find it to be the principal route for MHC class I presentation. Immunization with female spleen or DCs coated with the full complement of defined HY peptides, including the A(b)-restricted CD4+ Th cell determinant, failed to induce tetramer-reactive cells.

Rapid rejection of HLA-A2 transgenic skin graft due to indirect allorecognition

BACKGROUND

At present, it is not clear whether xenogeneic MHC molecules are recognized by T cells directly or indirectly through self-MHC-restricted presentation in a transplantation setting.

METHODS

We have transplanted skin from HLA-A2 transgenic (B6.A2) to nontransgenic C57BL/6 (B6) mice and investigated the subsequent mouse T-cell responses to HLA molecules, in vivo and in vitro.

RESULTS

Skin transplanted from transgenic B6.A2 to B6 mice was rejected rapidly, in 12-16 days. Although naive B6 mice did not respond to B6.A2 splenocytes in vitro, spleen cells from mice that underwent transplantation showed strong proliferative responses. An anti-B6.A2 T-cell line from mice that underwent transplantation made proliferative responses to B6.A2 splenocytes but did not recognize HLA-A2 on human cells or transfected allogeneic mouse cells. The indirect, self-H-2-restricted recognition of HLA-A2 implied by this was confirmed by the finding that lysates of HLA-A2-positive, but not HLA-A2-negative, human B cells were stimulatory when pulsed onto syngeneic antigen-presenting cells and by inhibition of anti-B6.A2 proliferation with both anti-mouse MHC class I and class II antibodies.

CONCLUSION

Our results suggest that indirect recognition of xenogeneic MHC antigen plays a predominant role in graft rejection.

Genetic analysis of a new mouse model for non-insulin-dependent diabetes

The TallyHo (TH) mouse strain is a newly established model for non-insulin-dependent diabetes mellitus (NIDDM). TH mice show obesity, hyperinsulinemia, hyperlipidemia, and male-limited hyperglycemia. A genetic dissection of the diabetes syndrome has been carried out using male backcross 1 progeny obtained from crosses between (C57BL/6J x TH)F1 and TH mice or (CAST/Ei x TH)F1 and TH mice. A genome-wide scan reveals three quantitative trait loci (QTLs), Tanidd1-3 (TH-associated NIDDM) linked to hyperglycemia. The major QTL (common in both crosses), Tanidd1, maps to chromosome (Chr) 19. Additionally, gene-gene interactions contributing to hyperglycemia have been observed between Tanidd1 and a locus on Chr 18 as well as between Tanidd2 and a locus on Chr 16. The overt hyperglycemia in TH mice is, therefore, likely due to a mutation in a major diabetes susceptibility locus on Chr 19, which interacts with additional genes to lead to an observable phenotype.

Buchu (Agathosma betulina and A. crenulata, Rutaceae) essential oils: their pharmacological action on guinea-pig ileum and antimicrobial activity on microorganisms

The mode of action of essential oils from two buchu species (Agathosma betulina and A. crenulata, Rutaceae) from the Cape region of South Africa has been studied on smooth muscle in-vitro using guinea-pig ileum. At high concentration, the oils had an initial spasmogenic activity followed by spasmolysis. The spasmolytic action was post-synaptic, not atropine-like and did not involve adrenoceptor or guanylyl cyclase activation. In the presence of the phosphodiesterase inhibitor rolipram, the spasmolytic action of A. betulina was significantly increased whilst that due to A. crenulata was also increased but not to a significant level. These results suggested a mode of action for the oils involving cyclic adenosine monophosphate. In addition, A. betulina appeared to block calcium channels but this was not seen with A. crenulata, possibly because the initial spasmogenic activity complicated the study of its spasmolytic action. Neither essential oil (10 microL, undiluted) demonstrated antimicrobial action against Enterococcus hirae and Pseudomonas aeruginosa but very low activity was observed against Escherichia coli, Saccharomyces cerevisiae and Staphylococcus aureus, suggesting little potential for these oils as antimicrobial agents/preservatives.

Low grade astrocytomas in the West of Scotland 1987-96: treatment, outcome, and cognitive functioning

BACKGROUND

Low grade astrocytomas are among the most common central nervous system tumours in children.

AIMS

To identify risk factors for the development of persistent intellectual handicap.

METHODS

The notes of 30 children with histologically proven low grade astrocytoma who presented during the period 1987-96 were reviewed. Thirteen of these children who were diagnosed with intracranial tumours between 1992 and 1996 underwent cognitive assessment one year after the completion of treatment.

RESULTS

Low grade astrocytomas were found in the cerebellum (59%), thalamus (17%), cerebral hemispheres (10%), and the cervical spinal cord (9%). Where possible all patients were treated with gross total resection of the tumour. Symptomatic children with tumours judged to be inoperable underwent biopsy followed by radiotherapy (13%). Three patients developed progressive disease following surgery and underwent repeat surgery and radiotherapy. Survival at a median follow up of 75 months (range 30-131) is 97%. At one year after the completion of treatment persisting cognitive impairment was common. The strongest predictor of IQ scores was the duration of symptoms of increased intracranial pressure preoperatively.

CONCLUSIONS

Although the overall survival rate of children with low grade astrocytoma is excellent, significant long term disability occurs. Early diagnosis is essential to reduce postoperative cognitive morbidity.

Gigantism due to growth hormone excess in a boy with optic glioma

True gigantism is rare in early childhood and is usually due to excess GH secretion from a pituitary adenoma. We report a case in which the endocrine abnormality is secondary to an optic glioma. Careful endocrine evaluation has shown that GH peak amplitude was not increased but rather there was failure of GH levels to suppress to baseline and a lack of pulsatility. There is no evidence of a direct secretory role for the tumour and we postulate that the tumour is affecting GH secretion through an effect on somatostatin tone. Specific tumour therapy is not indicated for this patient in the absence of mass effect or visual disturbance. The GH excess is being treated with somatostatin analogue (Octreotide) and as he has developed precocious puberty he is also receiving long acting GnRH analogue (Zoladex). This boy appears likely to have neurofibromatosis type 1 (NF1) which raises the question of subtle GH excess in NF1 patients with tall stature.

Booster seat use and reasons for nonuse

BACKGROUND

Many children 4 to 9 years old are inappropriately restrained in vehicles and are at risk for injury in crashes.

OBJECTIVES

This study was undertaken to determine the rate of booster seat use and the reasons for nonuse.

METHODS

Observations were conducted at a random sample of day care centers, and drivers of unrestrained children 4 to 8 years old were interviewed to determine the reasons for lack of booster seat use.

RESULTS

Observations were conducted on 149 children. Shoulder belt use significantly increased with the age of the child; 28.3% of 4-year-olds and 70.0% of 6- to 8-year-olds used lap-shoulder belts. Overall, 27.7% of children in the target age group used booster seats; only 10% of children 6 to 8 years old were restrained with booster seats. Booster seat use decreased when there were 3 or more passengers in the vehicle. The most common reason for lack of booster seat use was that parents thought the child was large enough to use the regular lap-shoulder belt system, or problems with attempting to use the seat in the vehicle. More than one half of parents who were not using booster seats at the time of the survey reported owning seats.

CONCLUSION

This study indicates that parental misconceptions about size and safety of regular restraint equipment are the most common reason that children are not appropriately restrained in vehicles. This information can be used to guide community intervention programs.

Anergic T cells inhibit the antigen-presenting function of dendritic cells

The phenomena of infectious tolerance and linked-suppression are well established, but the mechanisms involved are incompletely defined. Anergic T cells can inhibit responsive T cells in vitro and prolong skin allograft survival in vivo. In this study the mechanisms underlying these events were explored. Allospecific mouse T cell clones rendered unresponsive in vitro inhibited proliferation by responsive T cells specific for the same alloantigens. The inhibition required the presence of APC, in that the response to coimmobilized anti-CD3 and anti-CD28 Abs was not inhibited. Coculture of anergic T cells with bone marrow-derived dendritic cells (DC) led to profound inhibition of the ability of the DC to stimulate T cells with the same or a different specificity. After coculture with anergic T cells expression of MHC class II, CD80 and CD86 by DC were down-regulated. These effects did not appear to be due to a soluble factor in that inhibition was not seen in Transwell experiments, and was not reversed by addition of neutralizing anti-IL-4, anti-IL-10, and anti-TGF-beta Abs. Taken together, these data suggest that anergic T cells function as suppressor cells by inhibiting Ag presentation by DC via a cell contact-dependent mechanism.

Pica during pregnancy in low-income women born in Mexico

OBJECTIVE

To describe pica behavior (ingestion of nonfood items) in pregnant low-income Mexican-born women in Mexico and the United States.

DESIGN

A convenience sample of informants was interviewed with a questionnaire containing open-ended and closed-ended questions.

SETTING

A low-income community on the outskirts of Ensenada, Mexico, and clinics serving low-income people in southern California (Santa Ana, Bakersfield, and Los Angeles).

PARTICIPANTS

Of a total of 225 Mexican-born women, 75 (33%) were interviewed in Ensenada, and 150 (67%) were interviewed in southern California.

RESULTS

The prevalence of pica during pregnancy was 44% (n = 33) in the Ensenada group and 31% (n = 46) in the southern California group. Those who reported pica behavior more commonly had a relative who also practiced pica.

CONCLUSION

The high reported rate of pica in this sample indicates that pregnant Mexican-born women should be screened for pica and educated about the potentially serious effects on the fetus and mother.

The role of local estrogen biosynthesis in males and females

Natural (human) and experimental (mouse) models of estrogen insufficiency have revealed hitherto unexpected roles for estrogens in both males and females. In postmenopausal women, and in men, estrogen no longer has a major role as a circulating hormone, but rather it functions locally as a paracrine or even 'intracrine' factor in tissue sites where it is formed. As a consequence, the tissue-specific nature of aromatase production assumes physiological and pathophysiological significance. The availability of circulating precursors is also important in sites where there is no local supply of C19 precursors, particularly in elderly women. The potential clinical significance of these findings in terms of the development of new therapeutic modalities is discussed.

Dendritic cells permit identification of genes encoding MHC class II-restricted epitopes of transplantation antigens

Minor or histocompatibility (H) antigens are recognized by CD4+ and CD8+ T lymphocytes as short polymorphic peptides associated with MHC molecules. They are the targets of graft versus host and graft versus leukemia responses following bone marrow transplantation between HLA-identical siblings. Several genes encoding class I-restricted minor H epitopes have been identified, but approaches used for these have proved difficult to adapt for cloning class II-restricted minor H genes. We have combined the unique antigen-presenting properties of dendritic cells and high levels of episomal expression following transfection of COS cells to identify a Y chromosome gene encoding two HY peptide epitopes, HYAb and HYEk.

Absence of in vitro or in vivo bystander effects in a thymidine kinase-transduced murine T lymphoma

Among the goals of an optimal gene transfer system are a predictably high efficiency of transfer and the ability to confer stable gene expression. An additional benefit of strategies designed to target tumor or effector cells could be the induction of a bystander effect. Although tumor killing by the bystander effect in vivo has been obtained in several types of malignant tumors, it has not been reported for T lymphomas. The goals of this work were to determine the stability of the expression of the herpes simplex virus type-1 thymidine kinase and the low-affinity receptor for nerve growth factor truncated of its intracellular domain (deltaLNGFR) genes inserted in a murine T lymphoma; in addition, we sought to determine whether a bystander effect (direct or indirect) was present after treatment of the transduced tumor with ganciclovir. This study demonstrates a high level of stable expression of both genes in the T lymphoma in vitro and in vivo. However, we could not detect direct or indirect bystander effects in vivo mediated by the herpes simplex virus thymidine kinase/ganciclovir system in this tumor of lymphocyte origin. This is the first report to investigate bystander effects in vivo on a T-cell lineage tumor; in addition, this report has implications for the therapeutic transfer of non-transformed, antigen-specific T cells in vivo.

Histopathologic features of Burkholderia cepacia pneumonia in patients without cystic fibrosis

We present the histopathologic features of fatal Burkholderia cepacia pneumonia in three adults (one man [age 44 years] and two women [aged 40 and 43 years]). In all patients, the pulmonary infiltrates initially were localized (right middle lobe, left upper lobe, and right middle lobe) but rapidly progressed. Two open-lung biopsies and one pneumonectomy specimen showed necrotizing granulomatous inflammation merging with areas of more conventional necrotizing bronchopneumonia In one patient, a mediastinal lymph node also showed stellate necrotizing granulomas. Vasculitis was absent. B. cepacia was cultured from the open-lung biopsies and bronchial wash specimens in two patients and from postmortem cultures of lung, subcarinal lymph nodes, and blood in the third. The histopathology in these patients resembles that of melioidosis, which is caused by a related organism, Burkholderia pseudomallei. B. cepacia needs to be considered in the differential diagnosis of necrotizing granulomatous inflammation. In addition, given the rarity with which B. cepacia is identified as a cause of pneumonia in the immunocompetent host, isolation of B. cepacia should trigger a workup for underlying immunodeficiency or lead to an investigation to exclude the possibility of a nosocomial infection.

The human UTY gene encodes a novel HLA-B8-restricted H-Y antigen

The mammalian Y chromosome encodes male-specific minor histocompatibility (H-Y) Ags that are recognized by female T cells in an MHC-restricted manner. Two human H-Y epitopes presented by HLA-A2 and HLA-B7, respectively, have been identified previously and both are derived from the SMCY gene. We previously isolated CD8+ CTL clones that recognized a male-specific minor histocompatibility Ag presented by HLA-B8. In contrast to the SMCY-encoded H-Y epitopes, the B8/H-Y Ag was not presented by fibroblasts from male donors, suggesting that it was encoded by a novel gene. We now report that the HLA-B8-restricted H-Y epitope is defined by the octameric peptide LPHNHTDL corresponding to aa residues 566-573 of the human UTY protein. Transcription of the UTY gene is detected in a wide range of human tissues, but presentation of the UTY-derived H-Y epitope to CTL by cultured human cells shows significant cell-type specificity. Identification of this CTL-defined H-Y epitope should facilitate analysis of its contribution to graft/host interactions following sex-mismatched organ and bone marrow transplantation.

Identification of intervals on chromosomes 1, 3, and 13 linked to the development of lupus in BXSB mice

OBJECTIVE

To identify intervals containing systemic lupus erythematosus (SLE) susceptibility alleles in the BXSB strain of mice.

METHODS

We analyzed 286 (B10 x [B10 x BXSB]F1) backcross mice for a range of phenotypic traits associated with the development of SLE in BXSB mice. The mice were genotyped using 93 microsatellite markers, and the linkage of these markers to disease was studied by extreme-phenotype and quantitative trait locus analysis.

RESULTS

The disease phenotype in these backcross mice was less severe than that in BXSB mice. However, antinuclear antibody production was increased compared with the parental strain. We identified 4 areas of genetic linkage to disease on chromosome 1 (Bxs1-4), 1 on chromosome 3 (Bxs5), and another interval on chromosome 13 which were associated with various aspects of the phenotype. Bxs4 and Bxs5 are located in regions not previously linked to disease in other models of SLE.

CONCLUSION

SLE in the BXSB mouse model has a complex genetic basis and involves at least 5 distinct intervals located on chromosomes 1 and 3. There is evidence that different intervals affect particular aspects of the SLE phenotype.

Aromatase as a therapeutic target in endometriosis

In contrast to normal endometrium, the expression of aromatase is aberrant in endometriosis and is stimulated by prostaglandin E2 (PGE2). This results in local production of estrogen, which induces PGE2 formation and establishes a positive feedback cycle. Another abnormality in endometriosis--deficient 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) type 2 expression--impairs the inactivation of estradiol (E2) to estrone (E1). These molecular aberrations collectively favor accumulation of increasing quantities of E2, and PGE2 in endometriosis. The clinical relevance of these findings was exemplified by the successful treatment of an unusually aggressive case of postmenopausal endometriosis with an aromatase inhibitor.

Thymocyte antigens do not induce tolerance in the CD4+ T cell compartment

Thymocytes fail to tolerize the developing T cell repertoire to self MHC class I (MHC I) Ags because transgenic (CD2Kb) mice expressing H-2Kb solely in lymphoid cell lineages reject skin grafts mismatched only for H-2Kb. In this study, we examined why thymocytes fail to tolerize the T cell repertoire to self MHC I Ags. The ability of CD2Kb mice to reject H-2Kb skin grafts was age dependent because CD2Kb mice older than 20 wk accepted skin grafts. T cells from younger CD2Kb mice proliferated, but did not develop cytotoxic functions in vitro in response to H-2Kb. Proliferative responses were dominated by H-2Kb-specific, CD4+ T cells rather than CD8+ T cells. Representative CD4+ T cell clones from CD2Kb mice were MHC II restricted and recognized processed H-2Kb. TCR transgenic mice were generated from one CD4+ T cell clone (361) to monitor development of H-2Kb-specific immature thymocytes when all thymic cells or lymphoid cell lineages only expressed H-2Kb. Thymocyte precursors were not eliminated and mice were not tolerant to H-2Kb when Tg361 TCR transgenic mice were intercrossed with CD2Kb mice. In contrast, all thymocyte precursors were eliminated efficiently in thymic microenvironments in which all cells expressed H-2Kb. We conclude that self MHC I Ags expressed exclusively in thymocytes do not induce T cell tolerance because presentation of processed self MHC I Ags on self MHC II molecules fails to induce negative selection of CD4+ T cell precursors. This suggests that some self Ags are effectively compartmentalized and cannot induce self-tolerance in the T cell repertoire.

Estrogen production in endometriosis and use of aromatase inhibitors to treat endometriosis

Estrogen is the most important known factor that stimulates the growth of endometriosis. Estrogen delivery to endometriotic implants was classically viewed to be only via the circulating blood in an endocrine fashion. We recently uncovered an autocrine positive feedback mechanism, which favored the continuous production of estrogen and prostaglandin (PG)E2 in the endometriotic stromal cells. The enzyme, aromatase, is aberrantly expressed in endometriotic stromal cells and catalyzes the conversion of C19 steroids to estrogens, which then stimulate cyclooxygenase-2 to increase the levels of PGE2. PGE2, in turn, is a potent inducer of aromatase activity in endometriotic stromal cells. Aromatase is not expressed in the eutopic endometrium. Aromatase expression in endometriosis and its inhibition in eutopic endometrium are controlled by the competitive binding of a stimulatory transcription factor, steroidogenic factor-1, and an inhibitory factor, chicken ovalbumin upstream promoter-transcription factor to a regulatory element in the aromatase P450 gene promoter. In addition, we find that endometriotic tissue is deficient in 17beta-hydroxysteroid dehydrogenase type 2, which is normally expressed in eutopic endometrial glandular cells and inactivates estradiol-17beta to estrone. This deficiency is another aberration that favors higher levels of estradiol-17beta in endometriotic tissues in comparison with the eutopic endometrium. The clinical relevance of local aromatase expression in endometriosis was exemplified by the successful treatment of an unusually aggressive form of recurrent endometriosis in a postmenopausal woman using an aromatase inhibitor.

Local estrogen biosynthesis in males and females

It is now apparent that in men and in postmenopausal women, estrogens have important physiological and pathophysiological roles. However, importantly, these actions are at a local level, namely paracrine, autocrine, and even 'intracrine' rather than endocrine in the classical sense. Thus for example local estrogen biosynthesis in the bones of men plays a hitherto unsuspected role in the maintenance of bone mineralization and in epiphyseal fusion; and in the testes, estrogen is essential for male germ cell development. On the other hand, in postmenopausal women, the mesenchymal cells of the breast are the major source of estrogen responsible for breast cancer development. This realization points to the importance of circulating C19 precursors in the maintenance of adequate estrogen biosynthesis in extragonadal sites and suggests the possibility of new therapies to block estrogen synthesis in a tissue-specific fashion.

Surgical treatment of atypical mycobacterial cervicofacial adenitis in children

BACKGROUND

Atypical mycobacteria have long been recognized as a cause of cervicofacial adenitis in otherwise healthy children. The disease is nearly always localized but if left untreated the involved lymph nodes caseate and discharge. The management of this condition has been considered to be surgical with techniques including aspiration, incision and drainage, curettage and excision.

METHODS

Cases of atypical mycobacterial cervicofacial adenitis treated by curettage at the Canberra Hospital, ACT, Australia, are reviewed.

RESULTS

Ten cases successfully treated with curettage are reported. Two patients experienced delayed healing of their wounds and one required a second curettage 7 months after primary excision for recurrent disease.

CONCLUSION

Curettage is a safe and effective means of treating atypical mycobacterial cervicofacial adenitis in children. The primary cure rate of 70% is less than that for excision of the involved nodes (92% cure rate), which is the standard treatment for this disease.

Minor transplantation antigens: mouse models for human host-versus-graft, graft-versus-host and graft-versus-leukemia reactions

Minor transplantation or histocompatibility (H) antigens are barriers to the transplantation of organs and tissues between genetically non-identical individuals who are matched for transplantation antigens encoded by the major histocompatibility complex (MHC), H2 in mice and HLA in humans. Recognition of minor H antigens by T cells can lead to host-versus-graft (HvG) rejection of organs and, in bone marrow transplantation, to life threatening graft-versus-host (GvH) reactions, although if these can be controlled, clinically useful graft-versus-leukemia (GvL) reactions can be obtained. This review describes the early in vivo studies that laid the foundations of our understanding that minor H antigens are the product of genetic polymorphisms, the subsequent in vitro work which has identified these at the molecular level as peptides presented to T cells by self MHC molecules, and the most recent developments, which have seen the use of minor H specific T cells clones and sophisticated biochemical and molecular biological approaches to identify genes encoding them.

Melanoma antigen-encoding gene expression in melanocytic naevi and cutaneous malignant melanomas

Melanoma antigen-encoding (MAGE) genes encode peptides which are expressed by a proportion of malignant melanomas (MMs) and can be recognized in vitro by autologous cytolytic T lymphocytes in a human leucocyte-associated antigen (HLA)-restricted manner. Although expression of MAGE genes has been studied in cutaneous MMs, little is known about their expression in melanocytic naevi. We studied MAGE 1, 2, 3, 4, 6 and 12 gene expression in tissue from 10 benign melanocytic naevi, 14 dysplastic melanocytic naevi, three cutaneous MMs in situ, four primary cutaneous MMs and three distant metastatic MMs. MAGE gene expression was determined with reverse transcription-polymerase chain reaction (PCR) using random hexamers to generate cDNA from total tissue homogenate RNA followed by PCR using intron-spanning, MAGE-specific primer pairs. Controls were cDNA from MAGE-expressing melanoma cell lines. Expression of HLA class 1 was used as a cDNA quality control. MAGE 2, 4, 6 and 12 gene expression was not detected in any of the lesions studied. MAGE 1 and 3 gene expression was also not detected in any of the cases of benign and dysplastic melanocytic naevi and in situ MMs. One of four primary MMs expressed the MAGE 3 gene. Two of three distant metastatic MMs also expressed the MAGE 3 gene and one of these additionally expressed the MAGE 1 gene. Thus, MAGE gene expression appears to be a late event in the evolution of MMs.

Characterization of genes encoding translation initiation factor eIF-2gamma in mouse and human: sex chromosome localization, escape from X-inactivation and evolution

The Delta Sxrb interval of the mouse Y chromosome is critical for spermatogenesis and expression of the male-specific minor transplantation antigen H-Y. Several genes have been mapped to this interval and each has a homologue on the X chromosome. Four, Zfy1 , Zfy2 , Ube1y and Dffry , are expressed specifically in the testis and their X homologues are not transcribed from the inactive X chromosome. A further two, Smcy and Uty , are ubiquitously expressed and their X homologues escape X-inactivation. Here we report the identification of another gene from this region of the mouse Y chromosome. It encodes the highly conserved eukaryotic translation initiation factor eIF-2gamma. In the mouse this gene is ubiquitously expressed, has an X chromosome homologue which maps close to Dmd and escapes X-inactivation. The coding regions of the X and Y genes show 86% nucleotide identity and encode putative products with 98% amino acid identity. In humans, the eIF-2gamma structural gene is located on the X chromosome at Xp21 and this also escapes X-inactivation. However, there is no evidence of a Y copy of this gene in humans. We have identified autosomal retroposons of eIF-2gamma in both humans and mice and an additional retroposon on the X chromosome in some mouse strains. Ark blot analysis of eutherian and metatherian genomic DNA indicates that X-Y homologues are present in all species tested except simian primates and kangaroo and that retroposons are common to a wide range of mammals. These results shed light on the evolution of X-Y homologous genes.