Systemic treatment of venous leg ulcers with high doses of pentoxifylline: efficacy in a randomized, placebo-controlled trial

Several small studies have indicated that the systemic administration of pentoxifylline may accelerate healing of venous leg ulcers. The goal of this study was to further evaluate these findings in a larger scale placebo controlled trial and to explore the effect of the dose of pentoxifylline on healing. The study used a prospective, randomized, double-blind, parallel group placebo controlled design in a multicenter outpatient setting. Patients with one or more venous ulcer were enrolled, with all patients receiving standardized compression bandaging for treatment for their ulcers. Patients were also randomized to receive either pentoxifylline 400 mg, pentoxifylline 800 mg (two 400 mg tablets), or placebo tablets three times a day for up to 24 weeks. The main outcome measure was time to complete healing of all leg ulcers, using life table analysis. The study was completed as planned in 131 patients. Patients receiving 800 mg three times a day of pentoxifylline healed faster than placebo (p = 0.043, Wilcoxon test). The median time to complete healing was 100, 83, and 71 days for placebo, pentoxifylline 400 mg, and pentoxifylline 800 mg three times a day, respectively. Over half of all patients were ulcer free at week 16 (placebo) and at week 12 in both pentoxifylline groups. Whereas the placebo group had only achieved complete healing in half of the cases by week 16, all of the subjects remaining in the group receiving the high dose of pentoxifylline had healed completely. Treatment with pentoxifylline was well tolerated with similar drop-out rates in all three treatment groups. Complete wound closure occurred at least 4 weeks earlier in the majority of patients treated with pentoxifylline by comparison to placebo. A higher dose of pentoxifylline (800 mg three times a day) was more effective than the lower dose. We conclude that pentoxifylline is effective in accelerating healing of leg ulcers.

T-cell epitope mapping of the three most abundant extracellular proteins of Mycobacterium tuberculosis in outbred guinea pigs

The three most abundant extracellular proteins of Mycobacterium tuberculosis, the 30-, 32-, and 16-kDa major extracellular proteins, are particularly promising vaccine candidates. We have mapped T-cell epitopes of these three proteins in outbred guinea pigs by immunizing the animals with each protein and assaying splenic lymphocyte proliferation against a series of overlapping synthetic peptides covering the entire length of the mature proteins. The 30-kDa protein contained nine immunodominant epitopes, the 32-kDa protein contained two immunodominant epitopes, and the 16-kDa protein contained a highly immunodominant region at its N terminus. The immunodominant epitopes of the 30- and 32-kDa proteins in outbred guinea pigs were frequently identified in healthy purified-protein-derivative-positive or BCG-vaccinated individuals in previous studies. The immunodominant epitopes of these major extracellular proteins have potential utility in an epitope-based vaccine against tuberculosis.

Identification of fur, aconitase, and other proteins expressed by Mycobacterium tuberculosis under conditions of low and high concentrations of iron by combined two-dimensional gel electrophoresis and mass spectrometry

Iron plays a critical role in the pathophysiology of Mycobacterium tuberculosis. To gain a better understanding of iron regulation by this organism, we have used two-dimensional (2-D) gel electrophoresis, mass spectrometry, and database searching to study protein expression in M. tuberculosis under conditions of high and low iron concentration. Proteins in cellular extracts from M. tuberculosis Erdman strain grown under low-iron (1 microM) and high-iron (70 microM) conditions were separated by 2-D polyacrylamide gel electrophoresis, which allowed high-resolution separation of several hundred proteins, as visualized by Coomassie staining. The expression of at least 15 proteins was induced, and the expression of at least 12 proteins was decreased under low-iron conditions. In-gel trypsin digestion was performed on these differentially expressed proteins, and the digestion mixtures were analyzed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry to determine the molecular masses of the resulting tryptic peptides. Partial sequence data on some of the peptides were obtained by using after source decay and/or collision-induced dissociation. The fragmentation data were used to search computerized peptide mass and protein sequence databases for known proteins. Ten iron-regulated proteins were identified, including Fur and aconitase proteins, both of which are known to be regulated by iron in other bacterial systems. Our study shows that, where large protein sequence databases are available from genomic studies, the combined use of 2-D gel electrophoresis, mass spectrometry, and database searching to analyze proteins expressed under defined environmental conditions is a powerful tool for identifying expressed proteins and their physiologic relevance.

Localization of a baculovirus-induced chitinase in the insect cell endoplasmic reticulum

Confocal immunofluorescence microscopy was used to demonstrate that the Autographa californica nucleopolyhedrovirus (AcMNPV) chitinase was localized within the endoplasmic reticulum (ER) of virus-infected insect cells. This was consistent with removal of the signal peptide from the chitinase and an ER localization motif (KDEL) at the carboxyl end of the protein. Chitinase release from cells, a prerequisite for liquefaction of virus-infected insect larvae, appears to be aided by synthesis of the p10 protein. Deletion of p10 from the AcMNPV genome delayed the appearance of chitinase activity in the medium of virus-infected cells by 24 h and also delayed liquefaction of virus-infected Trichoplusia ni larvae by the same period.

The yiaE gene, located at 80.1 minutes on the Escherichia coli chromosome, encodes a 2-ketoaldonate reductase

An open reading frame located in the bisC-cspA intergenic region, or at 80.1 min on the Escherichia coli chromosome, encodes a hypothetical 2-hydroxyacid dehydrogenase, which was identified as a result of the E. coli Genome Sequencing Project. We report here that the product of the gene (yiaE) is a 2-ketoaldonate reductase (2KR). The gene was cloned and expressed with a C-terminal His tag in E. coli, and the protein was purified by metal-chelate affinity chromatography. The determination of the NH2-terminal amino acid sequence of the protein defined the translational start site of this gene. The enzyme was found to be a 2KR catalyzing the reduction of 2, 5-diketo-D-gluconate to 5-keto-D-gluconate, 2-keto-D-gluconate (2KDG) to D-gluconate, 2-keto-L-gulonate to L-idonate. The reductase was optimally active at pH 7.5, with NADPH as a preferred electron donor. The deduced amino acid sequence showed 69.4% identity with that of 2KR from Erwinia herbicola. Disruption of this gene on the chromosome resulted in the loss of 2KR activity in E. coli. E. coli W3110 was found to grow on 2KDG, whereas the mutant deficient in 2KR activity was unable to grow on 2KDG as the carbon source, suggesting that 2KR is responsible for the catabolism of 2KDG in E. coli and the diminishment of produced 2KDG from D-gluconate in the cultivation of E. coli harboring a cloned gluconate dehydrogenase gene.

California ground squirrel body temperature regulation patterns measured in the laboratory and in the natural environment

Body temperature (Tb) was measured by telemetry in both laboratory maintained and natural environment California ground squirrels, Spermophilus beecheyi. Laboratory animals had a mean diurnal Tb of 37.5 degrees C under conditions of LD 14:10, 20 degrees C and 36.5 degrees C under conditions of LD 10:14, 20 degrees C (P < 0.01). Nocturnal mean Tbs were 37.1 and 35.2 degrees C, respectively (P < 0.05). Mean diurnal Tbs for each animal in the natural environment ranged from 39.3 to 40.1 degrees C (mean = 39.6 degrees C) during both study seasons which included the hot season months of March through August and the cool season months of December through February. Natural environment hot season mean Tb was not significantly different from cool season mean Tb but both mean Tbs were significantly different from the diurnal mean Tbs measured in the laboratory (P < 0.05). California ground squirrels exhibit an open-field stress induced hyperthermia in the laboratory which can be extended for periods up to 6 h. The hyperthermic response is blocked by L-propranolol at a dosage of 15 mg kg-1. Laboratory animals do not habituate to repeated open-field exposures over a five consecutive day period. It is suggested that stress hyperthermia might be a normal component of thermoregulation in some free-living ground squirrels because of the openness of the habitat in which they exist.

Nutritional disorders in a concentration camp

OBJECTIVE

Observations on nutritional disorders were made by a physician inmate in a concentration camp before and during the Great Starvation in China.

METHODS/RESULTS

Based on therapeutic response, many unique abnormalities should be considered as a part of clinical picture of malnutrition, such as mucocutaneous pigmentation, nail layering phenomena and intranail hemorrhage, palmar/plantar fissures, vegetative system crisis, a avitaminostic fevers, multiple premature beats, and enlargement of cartilage, lymph nodes, and submandibular glands.

DISCUSSION

Thiamin deficiency should be also considered as one, if not the only, etiologic factor of several common disorders, including submandibular gland cyst, Baker's cyst, stenosing tenosynovitis, direct inguinal hernia, among others.

High-level heterologous expression and secretion in rapidly growing nonpathogenic mycobacteria of four major Mycobacterium tuberculosis extracellular proteins considered to be leading vaccine candidates and drug targets

Mycobacterium tuberculosis, the primary etiologic agent of tuberculosis, is the world's leading cause of death from a single infectious agent, and new vaccines and drugs to combat it are urgently needed. The major extracellular proteins of M. tuberculosis, which are released into its phagosome in macrophages, its host cells in humans, are leading candidates for a vaccine and prime targets for new drugs. However, the development of these biologicals has been hampered by the unavailability of large quantities of recombinant extracellular proteins identical to their native counterparts. In this report, we describe the heterologous expression and secretion of four major M. tuberculosis extracellular proteins (the 30-, 32, 16-, and 23.5-kDa proteins--the first, second, third, and eighth most abundant, respectively) in rapidly growing, nonpathogenic mycobacterial species. Multiple attempts to obtain secretion of the proteins by using Escherichia coli- and Bacillus subtilis-based expression systems were unsuccessful, suggesting that high-level expression and secretion of these Mycobacterium-specific proteins require a mycobacterial host. All four recombinant proteins were stably expressed from the cloned genes' own promoters at yields that were 5- to 10-fold higher than those observed for the native proteins. The four proteins were purified to apparent homogeneity from culture filtrates by ammonium sulfate precipitation and ion-exchange and molecular sieve chromatography. The recombinant proteins were indistinguishable from their native counterparts by multiple criteria. First, N-terminal amino acid sequence determination demonstrated that processing of the leader peptides was highly accurate. Second, sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis revealed identical migration patterns. Third, mass spectrometry analysis confirmed that differences in mass were < or = 5 Da. A homolog of the M. tuberculosis 30-kDa protein was identified in M. smegmatis by means of DNA analyses and immunoscreening. This is the first time that secretion of recombinant M. tuberculosis extracellular proteins in their native form has been achieved. This study opens the door to mass production of correctly processed and secreted extracellular proteins of M. tuberculosis in a heterologous host and allows ready evaluation of their biologic and immunologic function.

Streaming potentials in gap osteotomy callus and adjacent cortex. A pilot study

This study documented streaming potentials generated in vivo by maturing osteotomy calluses in 10 canine tibiae. Gap osteotomies were allowed to heal for 6 or 12 weeks and were stabilized by an external fixator. Then, with the dogs under anesthesia, electrical measurements were made from 3 silver-silver chloride electrodes placed surgically in direct contact with the callus, with adjacent cortical bone, and with the medullary canal (reference electrode). Streaming potentials were recorded during step loading and sinusoidal bending (0.1-30 Hertz) as the tibia was deformed by 2 threaded pins coupled to a servohydraulic device. Streaming potentials were generated at callus and adjacent cortical sites, but the magnitude was greater on the immature, flexible callus, where bending strain was concentrated; as the callus became increasingly rigid, strain and streaming potential magnitude were distributed more evenly over the callus and adjacent cortical fragments. When normalized to surface strain, mean streaming potential per strain was less dependent on the microscopic structure, although on individual specimens streaming potential per strain at callus and adjacent cortical bone sites tended to increase with decreasing porosity. Despite a wide variation in data in this pilot series, these observations are consistent with the natural history of callus maturation: the maximum magnitude of streaming potentials in callus appears to decrease as the strain gradient across the site decreases, whereas streaming potentials normalized to strain increase as bone matures and becomes more dense.

Noninvasive quantification of muscle oxygen in subjects with and without claudication

The disabling pain of intermittent claudication (IC) arises from oxygen deprivation in the lower limbs during walking. Measurement of the oxygen deficiency within the limb tissue now appears possible with recently expanded understanding of the photon transport through tissue for photons in the visible and near infrared range. Noninvasive measurement consists of preferentially measuring photons that have traveled more deeply into limb tissues and that, therefore, may reach locations of ischemic tissue. Oxygen measurements appear to be possible up to a depth approaching 1.5 cm beneath the surface of the skin. The present study reports on data acquired from the limbs of 11 subjects with IC and 12 subjects without IC. The subjects with IC are patients with clinical findings of claudication based upon segmental Doppler pressure profiles and subjective reports by the patient of pain during exercise. The subjects without IC are individuals with no prior history of ischemic vascular disease. The results consist of photon reflectance measurements at red and infrared wavelengths (approximately 660 nm and 880 nm respectively) taken before, during, and after exercise. Infrared reflectance indices are plotted as well as oxygenation indices generated from combining red and infrared reflectances. A compilation of exercise data shows responses that are generally consistent with the expected physiological responses to mild exercise in subjects with and without IC. We anticipate that the findings of this study may lead to an objective noninvasive testing procedure for measuring the ischemic and exercise-induced changes in muscle oxygenation in the presence of claudication. If the testing of ischemic hypoxia continues to show consistency and accuracy in determining the disability of the subjects with IC, future studies can more effectively test modes of conservative management, such as cessation of smoking, alternative exercise regimens, weight loss, and alternative pharmacological agents.

Formation of abdominal adhesions is inhibited by antibodies to transforming growth factor-beta1

Transforming growth factor-beta (TGF-beta) is an important factor in regulating the inflammatory response and the production of extracellular matrix by fibroblasts. These two processes are linked in the formation of fibrous adhesions after abdominal surgery. When the mesothelium is injured a fibrin strand is produced which is populated first by inflammatory cells then by fibroblasts which secrete extracellular matrix forming a permanent adhesion. TGF-beta promotes both chemotaxis of monocytes and the production of extracellular matrix by fibroblasts. We have used a model of abdominal adhesions in rats in which a circle of peritoneum is dissected and then sutured into place again. After 2 weeks the rats are euthanized and the adhesions are scored. Six groups of 10 rats each underwent this surgery. Group I served as the operative control. Group II was treated with saline which was injected immediately after surgery and on Days 1 and 2 after surgery (vehicle control). Using the same protocol with saline as vehicle, the other four groups of rats were treated with nonspecific IgG (150 microgram per day), anti-TGF-beta (panspecific, 167 microgram per day), anti-TGF-beta1 (67 microgram per day), or anti-TGF-beta2 (50 microgram per day). The rats injected with anti-TGF-beta1 had significantly lower adhesion scores (P < 0.05) than the controls. Rats injected with anti-TGF-beta2 or anti-TGF-beta (panspecific) did not differ significantly from the control saline-injected rats. The results indicate that specifically reducing levels of TGF-beta1 alone can be effective in preventing abdominal adhesions.

Novel insights into the genetics, biochemistry, and immunocytochemistry of the 30-kilodalton major extracellular protein of Mycobacterium tuberculosis

The 30/32-kDa complex of major secretory proteins are among the most important and intensively studied proteins of Mycobacterium tuberculosis. The proteins have been demonstrated to be immunoprotective and to play a central role in the physiology of the mycobacterium. In this study, we present a series of novel insights into this key protein complex arising out of a combination of genetic, biochemical, and immunocytochemical analyses. Our genetic analyses (i) indicate that the genes are arranged as separate transcription units, (ii) demonstrate that the mature 30-kDa protein of M. tuberculosis differs from the corresponding 30-kDa proteins of two strains of Mycobacterium bovis BCG by only 1 and 5 amino acids, (iii) suggest that expression of the proteins is regulated at the transcriptional level, and (iv) map the transcriptional start site of the 30-kDa protein gene. Our biochemical analyses provide evidence that (i) the 30-kDa protein and the two 32-kDa proteins (i.e., 32A and 32B) are secreted at a ratio of approximately 3:2:1, respectively, (ii) the proteins exist as monomers, (iii) the proteins are not posttranslationally modified by the addition of carbohydrates and lipids, (iv) the 30-kDa and 32A proteins contain one disulfide bridge, and (v) high-level expression and leader peptide processing are achievable in Escherichia coli. Our immunocytochemical analyses demonstrate that the 30/32-kDa complex is expressed in human monocytes and that the proteins are localized to the phagosomal space and the mycobacterial cell wall. These analyses fill important gaps in our knowledge of this critical protein complex of M. tuberculosis and, at the same time, raise new and fundamental questions regarding regulatory mechanisms that control coordinate expression of the proteins at a fixed ratio.

The correlation of ankle oscillometric blood pressures and segmental pulse volumes to Doppler systolic pressures in arterial occlusive disease

PURPOSE

This study was designed to evaluate the accuracy and failure rates of automatically collected oscillometric ankle systolic pressures (Psys) and pulse volumes (Pvol) using a new algorithm as compared with Psys obtained by standard manual Doppler-and-cuff technique.

METHODS

One hundred ten consecutive patients at a vascular laboratory had brachial and ankle Psys measured with the two methods. Pvol at or near the mean arterial pressure was also obtained automatically by the oscillometric device.

RESULTS

Both methods showed a 6.6% failure rate when measuring Psys at the ankle. Oscillometric Psys measurement was possible when Doppler Psys failed as a result of nonoccluding arteries. No difference was found between the two methods in occluding limbs with ankle-brachial indexes of 1.30 or more. Sequential brachial Psys values had a mean difference (Doppler-oscillometric) or 2 +/- 10.9 mm Hg and a correlation coefficient (r) of 0.92. Measurements at the ankle had a mean difference of -8.4 +/- 16.8 mm Hg and r = 0.90. These differences were not statistically significant. Mean arterial pressure Pvol recorded at the ankle also correlated with ankle Doppler Psys (r = 0.71) and showed a 1.9% failure rate.

CONCLUSION

Both automatic oscillometric plethysmographic Psys and Pvol at the ankle are shown to correlate well with Doppler-and-cuff Psys in patients with vascular disease. Oscillometric measurements can replace Doppler measurements in most clinical situations.

Surgery of the sympathetic nervous system

This article reviews the innervation of the arterial system of the lower extremity, lumbar sympathectomy in vascular surgery, lumbar sympathectomy for digital gangrene and in the prevention of major amputation of the lower extremity and substance P's role in neurogenic inflammatory modulation. Long-term results of lumbar sympathectomy and direct arterial bypass surgery have also been reviewed. In addition to the pilomotor, sudomotor and vasomotor actions of the sympathetic nervous system via its neurotransmitters, the molecular basis of the chronic neurogenic inflammatory reaction have been addressed with special attention to the discovery of substance P in the lumbar sympathetic chain and ganglia of human beings.

Role of embryonic factors in human implantation

Implantation biology is now at a stage where experimental science will be very productive in answering basic questions about the ability of an embryo to implant. The advancement of our knowledge of cytokines and growth factors has been critically important in fuelling the recent new understanding of embryo implantation. Specifically, our increased knowledge of the interleukin (IL)-1 system, as well as leukaemia-inhibiting factor (LIF), epidermal growth factor and colony-stimulating factor-1, and the availability of recombinant protein, specific antibodies and knockout mice, have led to a more detailed outline of implantation events. LIF and IL-1 are the two systems where recent advances have suggested their importance in implantation events. Recently, LIF has been shown in mice to be an endometrial requirement for implantation and embryo development. Although LIF is a pleiotropic molecule, with many interactions in multiple body tissues, in the uterus, concentrations are elevated on day 4 of pregnancy. Experiments with knockout mice have shown the requirement for endometrial LIF for successful implantation. The IL-1 system, consisting of two agonists (IL-1 alpha and IL-1 beta), two receptors (IL-1R types I and II) and the homologous IL-1 receptor antagonist (ra), has also been studied. Knowledge that the embryo secretes IL-1 suggested the interaction between embryonic IL-1 and endometrial receptor, which has been shown to occur. IL-1R type I is plentiful on endometrial epithelial cells and appears to interact with embryonically secreted IL-1 beta to favour implantation. Such implantation events in vivo in mice are blocked by the introduction of large quantities of IL-1ra, consistent with the hypothesis that appropriate interactions between agonist and receptor at the level of the endometrial surface are a requisite for successful implantation. As more specific information on each cytokine or growth factor system comes to light, more complete information on the multiple molecular steps of implantation will become apparent. However, it is clear that no single cytokine or growth factor will be able to explain the complicated events of embryo implantation. Such an important necessary phenomenon has multiple redundancies. The interactions between cytokines and growth factors are becoming increasingly apparent and will need more experimental evidence before a full understanding of implantation is available.

Compartment syndrome in the diabetic foot

The compartment syndrome is a well-described clinical entity that results from increased pressure within a myofascial compartment. The infection in a diabetic foot usually presents in the whole compartment and can spread to a neighboring compartment. The association of infection and increased compartment pressure in the diabetic foot makes its treatment a formidable challenge. Fasciotomies of the feet when indicated may accelerate infection control and wound healing in the diabetic foot. The presence of a compartment syndrome in the diabetic foot is seldom recognized. Awareness of this problem is mandatory for physicians dealing with diabetic feet.

Pulmonary scar carcinoma: report of three cases and review of the literature

Pulmonary scar carcinoma was described as a distinct clinicopathological entity over 50 years ago. There are many theories on the formation of this entity. We present three cases of pulmonary scar carcinoma with a high ratio of adenocarcinoma. One patient had a favorable postoperative course despite a 14-month delay in treatment. Necropsy specimen of another patient showed two primary scar carcinomas unrelated to each other. Literature review and discussion of etiology, diagnosis, and treatment modalities of pulmonary scar carcinoma were done. Pathogenesis and prognosis of the neoplasms associated with apical scars are not clearly understood.

Purification, characterization, and genetic analysis of Mycobacterium tuberculosis urease, a potentially critical determinant of host-pathogen interaction

Mycobacterium tuberculosis urease (urea amidohydrolase [EC 3.5.1.5]) was purified and shown to contain three subunits: two small subunits, each approximately 11,000 Da, and a large subunit of 62,000 Da. The N-terminal sequences of the three subunits were homologous to those of the A, B, and C subunits, respectively, of other bacterial ureases. M. tuberculosis urease was specific for urea, with a Km of 0.3 mM, and did not hydrolyze thiourea, hydroxyurea, arginine, or asparagine. The enzyme was active over a broad pH range (optimal activity at pH 7.2) and was remarkably stable against heating to 60 degrees C and resistant to denaturation with urea. The enzyme was not inhibited by 1 mM EDTA but was inhibited by N-ethylmaleimide, hydroxyurea, acetohydroxamate, and phenylphosphorodiamidate. Urease activity was readily detectable in M. tuberculosis growing in nitrogen-rich broth, but expression increased 10-fold upon nitrogen deprivation, which is consistent with a role for the enzyme in nitrogen acquisition by the bacterium. The gene cluster encoding urease was shown to have organizational similarities to urease gene clusters of other bacteria. The nucleotide sequence of the M. tuberculosis urease gene cluster revealed open reading frames corresponding to the urease A, B, and C subunits, as well as to the urease accessory molecules F and G.

Immunohistochemical localization, identification and regulation of the interleukin-1 receptor antagonist in the human endometrium

There is evidence suggesting the importance of the interleukin-1 receptor type I (IL-1Rtl) and interleukin-1 beta (IL-1 beta) as mediator in local intercellular interactions in endometrial tissue and embryonic implantation. To complete our understanding of the entire endometrial IL-1 system in humans, we have investigated the immunohistochemical distribution of IL-1 receptor antagonist (IL-1ra) in the human endometrium throughout the menstrual cycle. We have also identified the forms of IL-1ra present in human endometrial cells. Immunoreactive IL-1ra was found in both cryostat and paraffin-embedded sections of human endometrium using the alkaline phosphatase-peroxidase (A-P) method with two different IL-1ra antibodies. IL-1ra was present throughout the entire menstrual cycle, located primarily in the endometrial epithelium. However, IL-1ra staining was significantly higher during follicular phase in comparison with early and mid-late luteal phases. Reverse transcriptase polymerase chain reaction of cultured stromal and glandular cells showed that these cells express the intracellular form of IL-1ra mRNA (icIL-1ra). Our results demonstrate the regulated presence of the icIL-1ra in the human endometrium. This finding supports a possible autocrine-paracrine role for the IL-1 system in the human endometrium and embryonic implantation.

Identification of macrophage and stress-induced proteins of Mycobacterium tuberculosis

Using phosphorimager technology to quantitate differences in protein expression, we have investigated the modulation of protein synthesis by Mycobacterium tuberculosis in response to intracellular residence in human macrophages and, for comparison, in response to various stress conditions during extracellular growth. Proteins of M. tuberculosis growing intracellularly in human THP-1 cells and extracellularly in broth were labeled with [35S]methionine; during intracellular growth, host cell protein synthesis was inhibited with cycloheximide. The metabolically labeled proteins were separated by two-dimensional gel electrophoresis and quantitatively analyzed. Intracellular residence in macrophages induced a profound change in the overall phenotype of M. tuberculosis. The expression of at least 16 M. tuberculosis proteins was induced (at least a twofold increase compared with growth in broth) and 28 proteins repressed (at least a twofold decrease). Many of the phenotypic changes in protein expression induced during intracellular growth occurred during extracellular growth in response to stress conditions including heat-shock, low pH, and H2O2. However, the pattern of induced and repressed proteins was unique to each stress condition. Of the 16 macrophage-induced proteins, 6 were absent during extracellular growth under both normal and stress conditions. Such proteins are potential virulence determinants and/or they may be important in the cell-mediated and protective immune response to M. tuberculosis infection.

Pulmonary blastoma presenting as a solitary lip metastasis: case report and review of the literature

Pulmonary blastoma (PB) is an uncommon primary lung malignancy. This neoplasm was first described by Barrett and Barnard in 1945. The tumor is composed of immature epithelial and mesenchymal tissues which may recapitulate early embryological lung development. Under the microscope, the globular component resembles immature bronchus and connective tissue as seen in embryonic lung. More than one hundred cases have been reported in the literature. PB is more frequent in older people and in males and tends to affect blacks at younger ages. Symptomatology varies from asymptomatic to symptoms of a non-specific pulmonary disease. Cough, hemoptysis, dyspnea, chest pain, respiratory distress, fever, anorexia and weight loss are the most common presenting features. The most common roentgenologic pattern is a well-demarcated peripheral lesion, encapsulated by compression or atelectatic lung tissue, although in some cases there is a tendency to lobulation and cavitation. The size of the mass varies from a small peripheral nodule to a mass occupying the entire lobe or hemithorax. The treatment of choice has been surgical excision, radiation and, in selected cases, a combination of chemotherapy with radiation. The prognosis of this malignancy is poor; overall five-year survival is approximately 16 percent. No correlation has been established between histopathologic criteria and survival. The factors that indicate poor prognosis are tumor recurrence, metastasis at initial presentation, tumor size over 5 cm and lymph node metastasis. Liver, central nervous system and bones are the most frequent location of distant metastases. A rare case is presented of a pulmonary blastoma with an upper lip metastasis occurring in a paraplegic male. Diagnosis was confirmed by autopsy findings.(ABSTRACT TRUNCATED AT 250 WORDS)

Gonadal steroids modulate interleukin-1 receptor antagonist mRNA expression in cultured human monocytes

This study investigated whether gonadal steroids modulate the expression of the cytokine Interleukin-1 receptor antagonist in monocytes. Human male peripheral monocytes were isolated and cultured in serum free media with serially diluted concentrations of estradiol and progesterone. mRNA expressions with increasing steroid concentrations were compared by reverse transcription-polymerase chain reaction for intracellular and secretory interleukin-1 receptor antagonist specific primers and glyceraldehyde 3-phosphate dehydrogenase primers. Monocyte expression of secretory Interleukin-1 receptor antagonist mRNA was significantly elevated in the presence of normal physiological levels of estradiol (10(-11) M) and progesterone (10(-8) M), while expression was suppressed by higher concentrations of steroids. Intracellular receptor antagonist was also detected. This study is the first to describe the dose related response of cytokine interleukin-1 receptor antagonist to gonadal steroids.

Autonomic dysreflexia revisited

Autonomic dysreflexia (AD) is a clinical phenomenon that affects patients with spinal cord injury (SCI) above the major sympathetic outflow tract. The lesion is most often at or above the T-6 level. Any noxious stimuli below this level initiate reflex sympathetic activity resulting in life threatening hypertension uncontrollable by the feedback parasympathetic activity. The episodes of hypertension generally persist until the offending stimulus is removed. Absence of higher control over reflex sympathetic activity due to transection of the cord is an anatomical explanation of the phenomenon. Current evidence suggests additional factors such as supersensitivity and possibly increased numbers of spinal alpha adrenoreceptors and peripheral microvascular adrenoreceptors as well as accumulation of substance P below the lesion. It has been suggested that substance P acts as a modulator, initiating the sympathetic event to produce a strong, slow and prolonged excitatory action. Autonomic dysreflexia is further accentuated by the absence of gamma amino benzoic acid (GABA), norepinephrine (NE) and 5-hydroxytryptamine (5-HT) below the lesion. GABA is an inhibitory neurotransmitter. It has been suggested that either NE or 5-HT may also act as an inhibitory neurotransmitter. Resetting of the baroreceptors at a lower level also plays an important role. The anatomical transection at or above T-6 then helps in maintaining and accentuating the biochemical changes that develop in patients with high spinal cord lesions. The current article reviews the pathophysiology and management of this potentially life threatening, yet easily treatable, phenomenon.

Axillofemoral bypass graft in a spinal cord injured patient with impending gangrene

The axillofemoral bypass graft, an extra-anatomic graft, connects the axillary artery to the femoral artery and is used in the treatment of significant aortoiliac occlusive disease in poor-risk patients. A common indication for axillofemoral bypass is a "hostile abdomen" (postoperative adhesions, neoplasms or radiation). Less frequent indications are aortic mycotic aneurysm, infected aortobifemoral bypass graft, aortoduodenal fistula, inflammatory aneurysm and extensive retroperitoneal fibrosis. Spinal cord injured patients with peripheral arterial disease have two problems: 1) lack of premonitory symptoms (absence of claudication, paresthesias or rest pain) and 2) difficulty preventing pressure sores in the already poorly perfused limb. Indications for arterial reconstructive surgery are more drastic in this set of patients (impending gangrene and/or ischemic ulcers). Many spinal cord injured patients have sources of possible contamination (cystostomy and/or colostomy) which make intra-abdominal clean surgery impossible. We present a spinal cord injured patient with a permanent cystostomy and impending gangrene of the left foot. He underwent a left axillofemoral bypass graft and had a good postoperative course. We conclude that axillofemoral bypass graft is a good alternative for limb salvage in the spinal cord injured patient, especially when there is a source of possible contamination (colostomy and/or cystostomy) that would interfere with more common bypass grafting. The role of the noninvasive vascular laboratory for early detection of vascular disease is emphasized.

Small (< or = 3 cm) renal masses: correlation of spiral CT features and pathologic findings

OBJECTIVE

We describe our 3-year experience using spiral CT in the evaluation of small renal masses in order to determine the usefulness of this technique for classifying the lesions and to correlate specific CT features with pathologic findings.

MATERIALS AND METHODS

We retrospectively analyzed spiral CT scans and results of pathologic examinations of surgically extirpated small (< or = 3 cm) renal masses in 35 patients. The masses included 27 renal cell carcinomas, two transitional cell carcinomas, one leiomyoma, one angiomyolipoma, and four benign cysts. Several imaging features, including attenuation, pattern of contrast enhancement, presence and type of calcification, cyst wall, and septation, were correlated with pathologic findings.

RESULTS

Most renal cell carcinomas had a solid growth pattern (n = 19), had attenuation values on unenhanced scans of 20 H or greater (n = 26), and had attenuation values that increased by at least 10 H with contrast enhancement (n = 26). Only three renal cell carcinomas were mostly cystic on pathologic examination. Heterogeneous enhancement correlated with the presence of acellular regions (p = .02). Of 12 cystic masses, spiral CT showed the absence of a thick or nodular fibrous capsule in seven of nine masses (specificity, 0.78) and the absence of several (or nodular) septations in six of seven masses (specificity, 0.86) but was not as sensitive in detecting these features.

CONCLUSION

Spiral CT can show many of the key imaging features of small renal masses used to distinguish between benign and malignant lesions. However, despite the theoretical benefits of volumetric CT, some lesions remain indeterminate and require surgical removal for diagnosis.