Innovative clinical trial designs to rationalize TB vaccine development.

A recent trial of a leading tuberculosis (TB) vaccine candidate in 3000 South African infants failed to show protection over that from BCG alone, and highlights the difficulties in clinical development of TB vaccines. Progression of vaccine candidates to efficacy trials against TB disease rests on demonstration of safety and immunogenicity in target populations and protection against challenge in preclinical models, but immunologic correlates of protection are unknown, and animal models may not be predictive of results in humans. Even in populations most heavily affected by TB the sample sizes required for Phase 2b efficacy trials using TB disease as an endpoint are in the thousands. Novel clinical trial models have been developed to evaluate candidate TB vaccines in selected populations using biologically relevant outcomes and innovative statistical approaches. Such proof of concept studies can be used to more rationally select vaccine candidates for advancement to large scale trials against TB disease.

Designing an adaptive phase II/III trial to evaluate efficacy, safety and immune correlates of new TB vaccines in young adults and adolescents.

This article summarises the consensus arrived at a meeting of South African and international stakeholders on specific late phase clinical trial design issues integrating the investigation of immune correlates as an integral part of a phase III protocol for a preventative TB vaccine in an adolescent/adult population. The challenge ahead is to optimize the planning for phase 3 TB vaccine preventative trials, under resource constraints, given that there are no known correlates of protection to shorten and increase the efficiencies of efficacy trials. An adaptive, multi-arm, group sequentially designed trial protocol is proposed incorporating design features that address uncertainties arising from both advances in the field and dynamic study populations and disease states. Such a design allows modifications that protect research subjects, save time, and maximize the impact of scarce financial resources. Further, the protocol underwent joint review by regulators from several African nations at a meeting of the African Vaccine Regulatory Forum (AVAREF), a regional regulatory harmonization initiative, and recommendations are included.

A proposed national strategy for tuberculosis vaccine development.

The global tuberculosis epidemic causes approximately 5% of deaths worldwide. Despite recent concerted and largely successful tuberculosis control efforts, the incidence of tuberculosis in the United States remains 74-fold higher than the stated elimination goal of <1 case per million population by the year 2010. Current bacille Calmette-Guérin vaccines, although efficacious in preventing extrapulmonary tuberculosis in young children, have shown widely variable efficacy in preventing adult pulmonary tuberculosis, confound skin test screening, and are not recommended for use in the United States. The Advisory Council for Elimination of Tuberculosis recently stated that tuberculosis would not be eliminated from the United States without a more effective vaccine. Recent scientific advances have created unprecedented opportunity for tuberculosis vaccine development. Therefore, members of the broad tuberculosis research and control communities have recently created and proposed a national strategy, or blueprint, for tuberculosis vaccine development, which is presented here.

Leprosy research--setting priorities and facilitating collaborations: a personal perspective.

In recent years, as the prevalence of leprosy has declined and the tuberculosis epidemic has gained increasing attention, leprosy research has generally taken a 'back seat' to research in tuberculosis and other emerging and re-emerging infections. This has resulted as much from perceived differences of scientific opportunities in these fields as from differences of the disease burden. At the United States National Institutes of Health (NIH), research priority setting is typically based on a number of factors. In the case of leprosy research, the technical difficulties associated with this scientific area have clearly lessened enthusiasm for and progress in this field. Today, however, we are confronted by the reality of not having sufficient scientific understanding to explain a stable or increasing number of leprosy cases detected annually in the face of a dramatically decreasing total number of identified cases. We also lack adequate tools for diagnosis and prevention. At the same time, new molecular and cellular approaches and knowledge of the complete sequence of the genome of Mycobacterium leprae render leprosy research significantly more tractable than ever before. The combination of these factors has led a number of groups, including the National Institute of Allergy and Infectious Diseases of the NIH, to review the current state of knowledge in leprosy research and draft recommendations for future leprosy research priorities. It is clear that many of the necessary and exciting research activities can best be addressed through collaborations among investigators, with control programmes, and among countries of high and low endemicity.

The tuberculosis epidemic. Scientific challenges and opportunities.

One in every three people on Earth is believed to be infected with Mycobacterium tuberculosis, leading to seven to eight million cases of active tuberculosis (TB) per year and approximately three million deaths annually. this epidemic, like those of most infectious diseases, creates scientific challenges and opportunities as it raises the demand for public health solutions. The currently available weapons for fighting TB are inadequate. The ultimate goal of biomedical TB research is to lessen the public health burden of this disease by developing improved diagnostic, therapeutic, and intervention strategies. Achieving this goal requires a base of knowledge about the biology of M. tuberculosis and related mycobacteria, their interactions with human and animal hosts, and the nature of an effective host-protective immune response. TB researchers are applying this accumulating base of knowledge to developing rapid, easy-to-use diagnostic assays appropriate for low-as well as high-income countries, improving the current complicated therapeutic regimen, identifying potential new drugs to combat multidrug-resistant TB, and creating more effective vaccines.

Mondor's disease of the breast resulting from jellyfish sting.

OBJECTIVE: To present two cases of Mondor's disease of the breast resulting from jellyfish stings in Western Australia. CLINICAL FEATURES: A 30-year-old Caucasian woman presented with a palpable thickened cord in her right breast. The straightness of the cord suggested a thrombosed lymphatic. A 50-year-old Caucasian woman presented with an obvious palpable cord extending most of the length of her left breast. Mammography demonstrated no abnormality. Both women reported having been stung by jellyfish a month earlier. INTERVENTION AND OUTCOME: As Mondor's disease is a benign, self-limiting disease, the patients were reassured and reviewed routinely. In each case, the condition settled spontaneously over a period of several weeks. CONCLUSION: Jellyfish stings should be recognised as an unusual variant of the numerous causes which have been described for Mondor's disease.

Mutations of the retinoblastoma gene in human lymphoid neoplasms.

The inactivation or loss of tumor suppressor genes (anti-oncogenes) has been implicated as a mechanism central to the pathogenesis of many solid tumors. More recently, we and others have identified a role of one rumor suppressor gene, the retinoblastoma gene, in the development of human lymphoid lymphoma and leukemia. Here we review the involvement of the retinoblastoma gene in the control of normal lymphocyte cell division and the consequences of inactivation of the retinoblastoma gene for the development of lymphoid neoplasia. Our survey has disclosed a broad involvement of retinoblastoma gene inactivation in a wide variety of non-Hodgkin's lymphomas and lymphocytic leukemia. Based on these early findings, it appears likely that tumor suppressor genes may well be involved in many hematopoietic neoplasma.

Oncogene rearrangements in chronic B-cell leukemia.

Forty-four B-chronic lymphocytic leukemias (CLL) were studied by Southern blot analysis using probes for the Ig genes and bcl-1, bcl-2 (major, minor and 5' breakpoint region), bcl-3, c-myc, and retinoblastoma (Rb) loci. Eight cases had three or more rearranged JH bands, indicating oligoclonality, clonal evolution, or chromosomal translocation. One case had a rearrangement of the bcl-1 locus and three of the bcl-2 locus. In the first case, comigration of the rearranged bcl-1 and JH sequences indicated a t(11;14)(q13;q32) translocation, which, in contrast to previously described cases, seems to be completely reciprocal. One case with a bcl-2 rearrangement showed comigration of the bcl-2 major breakpoint region and a rearranged JH band. This indicates a t(14;18) (q32;q21). The two other cases showed rearrangements of the bcl-2 5' breakpoint region without apparent comigration. No rearrangements were detected of c-myc and bcl-3, located at chromosome 19, nor was a deletion of Rb found. All but three cases had CD5 expression. The exceptions included the t(11;14) and the t(14;18) cases. Our results confirm recent data on rearrangements at the 5' site of bcl-2 in CLL. Additionally, they corroborate the presumption that CD5-negative chronic B-cell leukemias should be considered apart from classical CLL.

Inactivation of the retinoblastoma gene in human lymphoid neoplasms.

The absence of wild type retinoblastoma (Rb) gene expression in a wide variety of human solid tumors suggests an etiologic role for this tumor suppressor gene in human cancer. We have evaluated the involvement of Rb gene inactivation in the pathogenesis and progression of human lymphoma and leukemia. We examined the genomic configuration and transcription of the Rb gene in cultured cell lines and primary cases of T- and B-cell lymphomas and leukemias. By Southern analysis, abnormalities of the Rb locus were identified in 1 of 5 T-cell acute lymphoblastic lymphoma (T-ALL) cell lines, 1 of 26 primary cases of T-ALL, 1 of 40 primary cases of chronic lymphocytic lymphoma/well-differentiated lymphoma (CLL/WDL), and 1 of 15 primary cases of intermediately differentiated lymphoma (IDL). By Northern analysis, markedly reduced or abnormal expression of the Rb gene was identified in 2 of 5 T-ALL cell lines, 1 of 7 primary cases of T-ALL, 1 of 5 primary cases of CLL/WDL, and 1 of 6 primary cases of IDL. These findings show that Rb gene inactivation can be associated with a broad range of lymphoid neoplasms and that loss of the tumor suppressor function of Rb may influence the pathogenesis and progression of lymphoma/leukemia.

Disruption of the human SCL locus by "illegitimate" V-(D)-J recombinase activity.

A fusion complementary DNA in the T cell line HSB-2 elucidates a provocative mechanism for the disruption of the putative hematopoietic transcription factor SCL. The fusion cDNA results from an interstitial deletion between a previously unknown locus, SIL (SCL interrupting locus), and the 5' untranslated region of SCL. Similar to 1;14 translocations, this deletion disrupts the SCL 5' regulatory region. This event is probably mediated by V-(D)-J recombinase activity, although neither locus is an immunoglobulin or a T cell receptor. Two other T cell lines, CEM and RPMI 8402, have essentially identical deletions. Thus, in lymphocytes, growth-affecting genes other than immune receptors risk rearrangements.

Prevalence of cryptosporidiosis in patients undergoing endoscopy: evidence for an asymptomatic carrier state.

PURPOSE: We sought to determine the presence of the parasite cryptosporidium in the duodenal aspirates of patients undergoing routine upper gastrointestinal endoscopy. PATIENTS AND METHODS: The study consisted of 169 patients undergoing upper endoscopy or endoscopic retrograde cholangiopancreatography. Immunocompromised patients were not included in the study population. Samples were aspirated from the second portion of the duodenum. Biopsy specimens were also obtained. Three randomly passed stool samples were obtained from 75% of the patients who were found to have cryptosporidium in the duodenum. RESULTS: Overall, cryptosporidium oocysts were identified in 12.7% of patients. There was no significant difference in the prevalence of the parasite in any subgroup of procedure or symptom complex. Half of those (46.7%) with positive aspirates had demonstrable cryptosporidium in stool samples, although none of the patients had diarrhea. No patient had detectable cryptosporidium in biopsy samples of the duodenum. CONCLUSION: The findings suggest a surprisingly high asymptomatic carrier rate for cryptosporidium.

MR and CT findings in pulmonary artery sarcoma.

Pulmonary artery sarcomas are a rare and frequently forgotten cause of pulmonary artery occlusion. We present a case report that details magnetic resonance and new CT findings, which may help establish early diagnosis of this infrequently encountered tumor.

Cunninghamella bertholletiae infection associated with deferoxamine therapy.

Cunninghamella bertholletiae, an uncommon cause of human infection, has been reported with increasing frequency in recent years. C. bertholletiae belongs to the order Mucorales and produces infections similar to those produced by the other agents of mucormycosis. Infections with this group of organisms have typically been seen either in patients with diabetes mellitus or in those receiving chemotherapy. Recent reports of mucormycosis in dialysis patients receiving deferoxamine for iron or aluminum overload have raised the possibility that deferoxamine therapy is a risk factor for mucormycosis. A case of C. bertholletiae infection in a patient receiving deferoxamine for iron overload unrelated to hemodialysis was investigated in detail, and possible explanations for this patient's infection were assessed.

Xenopus 5S gene transcription factor, TFIIIA: characterization of a cDNA clone and measurement of RNA levels throughout development.

Initiation of 5S RNA gene transcription in Xenopus oocytes requires a 38,500 dalton polypeptide, TFIIIA. The levels of both 5S RNA and TFIIIA are regulated throughout oogenesis and embryonic development. To delineate the mechanisms by which the corresponding genes are regulated, as well as to determine the primary structure of TFIIIA, we have isolated a cDNA clone that encodes TFIIIA. Using the cDNA clone, we have determined that there is (are) one or a small number of TFIIIA gene(s) per Xenopus haploid genome, and we have estimated the size and levels of TFIIIA RNA throughout Xenopus development. We report sequence homologies between TFIIIA cDNA and regulatory regions of the Xenopus tmet and 5S RNA genes. Implications of these data for developmental regulation of the TFIIIA and 5S RNA genes are discussed.

beta 2- and alpha 2-adrenergic receptors and receptor coupling to adenylate cyclase in human mononuclear leukocytes and platelets in relation to physiological variations of sex steroids.

In view of evidence, largely in animals, indicating effects of sex steroids on adrenergic receptors, we measured mononuclear leukocyte (MNL) beta 2-adrenergic receptors and adenylate cyclase sensitivity to stimulation by isoproterenol as well as platelet alpha 2-adrenergic receptors and sensitivity of sodium fluoride-stimulated adenylate cyclase to inhibition by epinephrine in 3 groups of normal humans with physiologically disparate levels of testosterone, estradiol, and progesterone (10 normal men and 10 normal women, the latter sampled in both the follicular and luteal phases of their menstrual cycles). Differences in testosterone, estradiol, and progesterone were as expected; testosterone levels were 10-fold higher in men, and progesterone levels were 20-fold higher in luteal phase women. T4, cortisol , and norepinephrine levels did not differ. Basal plasma epinephrine concentrations were slightly but significantly higher in luteal phase women [34 +/- 5 (+/-SE) pg/ml] than in follicular phase women (16 +/- 3 pg/ml; P less than 0.01) or men (20 +/- 3 pg/ml; P less than 0.05). There were no significant differences among these 3 groups in the densities or affinities of MNL beta 2-adrenergic or platelet alpha 2-adrenergic receptors or in the corresponding MNL and platelet adenylate cyclase sensitivities. Thus, there is not a generalized effect of physiological variations of testosterone, estradiol, and progesterone on adrenergic receptors or adenylate cyclase. To the extent that the adrenergic receptors and adenylate cyclase activities of circulating cells reflect those of extravascular catecholamine target cells, these data provide no support for a role of physiological variations of testosterone, estradiol, or progesterone in the regulation of catecholamine action in humans.

Triiodothyronine-induced thyrotoxicosis increases mononuclear leukocyte beta-adrenergic receptor density in man.

beta-Adrenergic receptors are increased in some tissues of experimentally thyrotoxic animals but are reported to be unchanged in mononuclear leukocytes of spontaneously thyrotoxic humans. We examined the effects of triiodothyronine (100 mug/d for 7 d) and placebo on high-affinity mononuclear leukocyte beta-adrenergic receptors in 24 normal human subjects, using a double-blind design. beta-Adrenergic receptors were assessed by specific binding of the antagonist (-)[(3)H]dihydroalprenolol. Triiodothyronine administration resulted in objective evidence of moderate thyrotoxicosis and an increase in mean (-)[(3)H]dihydroalprenolol binding from 25+/-3 to 57+/-9 fmol/mg protein (P < 0.001). The latter was attributable, by Scatchard analysis, to an increase in beta-adrenergic receptor density (967 +/- 134 to 2250 +/- 387 sites per cell, P < 0.01); apparent dissociation constants did not change. Placebo administration had no effects. Marked inter- and intraindividual variation in mononuclear leukocyte beta-adrenergic receptor density was also noted. Because this was approximately threefold greater than analytical variation, it is largely attributable to biologic variation. Thus, we conclude: (a) The finding of a triiodothyronine-induced increase in mononuclear leukocyte beta-adrenergic receptor density in human mononuclear leukocytes, coupled with similar findings in tissues of experimentally thyrotoxic animals, provides support for the use of mononuclear leukocytes to assess receptor status in man. (b) There is considerable biologic variation in beta-adrenergic receptor density in man. (c) The findings of thyroid hormone-induced increments in beta-adrenergic receptor density provide a plausible mechanism for the putative enhanced responsiveness to endogenous catecholamines of patients with thyrotoxicosis.