Molecular dynamics simulation in solvent of the estrogen receptor protein DNA binding domain in complex with a non-consensus estrogen response element DNA sequence.

We investigated protein/DNA interactions, using molecular dynamics simulations computed between a 10 Angstom water layer model of the estrogen receptor (ER) protein DNA binding domain (DBD) amino acids and DNA of a non-consensus estrogen response element (ERE) consisting of 29 nucleotide base pairs. This ERE nucleotide sequence occurs naturally upstream of the Xenopus laevis Vitelligenin A1 gene. The ER DBD is encoded by three exons. Namely, exons 2 and 3 which encode the two zinc binding motifs and a sequence of exon 4 which encodes a predicted alpha helix. We generated a computer model of the ER DBD using atomic coordinates derived from the average of 30 nuclear magnetic resonance (NMR) spectroscopy coordinate sets. Amino acids on the carboxyl end of the ER DBD were disordered in both X-ray crystallography and NMR determinations and no coordinates were reported. This disordered region includes 10 amino acids of a predicted alpha helix encoded in exon 4 at the exon 3/4 splice junction. These amino acids are known to be important in DNA binding and are also believed to function as a nuclear translocation signal sequence for the ER protein. We generated a computer model of the predicted alpha helix consisting of the 10 amino acids encoded in exon 4 and attached this helix to the carboxyl end of the ER DBD at the exon 3/4 splice junction site. We docked the ER DBD model within the DNA major groove halfsites of the 29 base pair non-consensus ERE and flanking nucleotides. We constructed a solvated model with the ER DBD/ERE complex surrounded by a ten Angstrom water layer and conducted molecular dynamics simulations. Hydrogen bonding interactions were monitored. In addition, van der Waals and electrostatic interaction energies were calculated. Amino acids of the ER DBD DNA recognition helix formed both direct and water mediated hydrogen bonds at cognate codon-anticodon nucleotide base and backbone sites within the ERE DNA right major groove halfsite. Amino acids of the ER DBD exon 4 encoded predicted alpha helix formed direct and water mediated H-bonds with base and backbone sites of their cognate codon-anticodon nucleotides within the minor grooves flanking the ERE DNA major groove halfsites. These interactions together induced bending of the DNA into the protein.

Disc space infection.

Disc space infection or discitis, an infection of the intervertebral disc with contiguous subchondral vertebral osteomyelitis, most frequently follows prior intervertebral disc surgery or arises by hematogenous dissemination. The majority of cases are located in the lumbosacral spine and are caused by staphylococci. Clinical findings include localized spinal pain and fever. The diagnosis is suggested by radiologic studies (plain x-ray, bone scan, CT scan and MR imaging) and confirmed by culturing blood or material obtained from the involved disc space. Treatment consists of antimicrobial therapy, spinal immobilization and surgical intervention in selected circumstances. Discitis is associated with a good prognosis but residual back pain, limited spinal mobility and neurologic deficit may occur.

Conservation of genetic information: a code for site-specific DNA recognition.

We present findings of genetic information conservation between the glucocorticoid response element (GRE) DNA and the cDNA encoding the glucocorticoid receptor (GR) DNA-binding domain (DBD). The regions of nucleotide sub-sequence similarity to the GRE in the GR DBD occur specifically at nucleotide sequences on the ends of exons 3,4, and 5 at their splice junction sites. These sequences encode the DNA recognition helix on exon 3, a beta-strand on exon 4, and a putative alpha-helix on exon 5, respectively. The nucleotide sequence of exon 5 that encodes the putative alpha-helix located on the carboxyl terminus of the GR DBD shares sequence similarity with the flanking nucleotide regions of the GRE. We generated a computer model of the GR DBD using atomic coordinates derived from nuclear magnetic resonance spectroscopy to which we attached the exon 5-encoded putative alpha-helix. We docked this GR DBD structure at the 39-base-pair nucleotide sequence containing the GRE binding site and flanking nucleotides, which contained conserved genetic information. We observed that amino acids of the DNA recognition helix, the beta-strand, and the putative alpha-helix are spatially aligned with trinucleotides identical to their cognate codons within the GRE and its flanking nucleotides.

Aquatic hazard Mycobacterium marinum infection.

We describe two patients with Mycobacterium marinum infection and review the pertinent literature. M. marinum infection follows trauma, often trivial, in water or from marine life. Clinical manifestations include superficial cutaneous lesions which are either solitary or multiple in a sporotrichoid distribution, involvement of the deeper structures of the hand and wrist and disseminated disease. Biopsy of infected tissue reveals a mixed suppurative-granulomatous reaction with sparse to absent acid-fast bacilli. Definitive diagnosis is achieved by growing the organism from appropriate specimens. Suggested therapeutic regimens consist of rifampin and ethambutol for advanced disease and infection invading the deeper structures of the hand and wrist and one of the tetracyclines or trimethoprim-sulfamethoxazole for early or minimal disease. Surgical debridement is advised when there is persistent pain, a discharging sinus or previous local injection of corticosteroids.

Staphylococcus aureus endocarditis in community hospitals.

We compared 13 cases of Staphylococcus aureus endocarditis from community hospitals to previous series all of which originated from university or tertiary care hospitals. In our experience Staph. aureus was the third leading cause of endocarditis and accounted for 20% of cases. The infection presented as one of three syndromes: native valve endocarditis, prosthetic valve endocarditis and endocarditis in drug addicts. Laboratory data revealed leukocytosis; infiltrates, nodules, congestive heart failure and cardiomegaly were seen on chest x-ray; and echocardiography infrequently detected vegetations. Criteria which favored the diagnosis of endocarditis in staphylococcemic patients were: absence of a primary site of infection, community acquisition of infection, metastatic infectious sequelae and vegetations documented by echocardiography. Treatment requires prolonged intravenous administration of high dose bactericidal antimicrobial agents; commonly nafcillin or oxacillin combined for a variable period with gentamicin. The mortality rate in our series was 23% and complications occurred in 70% of cases.

Mucormycosis: a community hospital perspective.

Mucormycosis (synonymous with phycomycosis and zygomycosis) is a devastating fungal infection which usually involves patients with diabetes mellitus, often complicated by ketoacidosis, and malignant neoplasms, commonly leukemia and lymphoma. Clinical manifestations include rhinocerebral, pulmonary, disseminated, isolated cerebral, gastrointestinal and cutaneous disease. Common to all forms of mucormycosis is vascular invasion with production of necrotic tissue. The diagnosis is achieved by demonstrating broad, non-septate hyphae with right-angle branching in a tissue biopsy specimen. Successful treatment consists of early diagnosis, intensive systemic antifungal therapy with amphotericin B, aggressive surgical debridement and control of the underlying disease. In our experience with mucormycosis at Huntsville Hospital, the patients were immuno- compromised and the infection was restricted to the lung. Despite use of amphotericin B in all patients, the only one who survived underwent surgical section of infected tissue.

Coagulase-negative staphylococcal endocarditis: a view from the community hospital.

Review of our experience with infectious endocarditis at a single community hospital showed coagulase-negative staphylococci to be our leading cause of endocarditis. The pathogenesis of coagulase-negative staphylococcal endocarditis (CNSE) involved either hematogenous seeding of native or prosthetic valves, or direct implantation at surgery. Cases involving native valves demonstrated an acute onset and rapidly deteriorating course, while prosthetic valve endocarditis was more indolent; both types were associated with multiple complications. Although the number of our cases is small, mortality from native valve CNSE was higher than that of prosthetic valve endocarditis. Patients treated medically fared better than those receiving both medical and surgical treatment, though the medically treated group may not have been as ill as those having valve replacement. Vancomycin caused serious adverse effects in two of the five patients receiving it.

Chronic mandibular osteomyelitis.

Chronic osteomyelitis of the mandible is an infrequently reported condition, but recent experience with six cases over a 14-month period suggests it is more common than appreciated. Chronic mandibular osteomyelitis results from odontogenic infection, postextraction complication, trauma, or irradiation to the mandible. Clinical findings include local pain and swelling and trismus, but constitutional symptoms are unusual. Radiologic examination discloses radiolucent areas, bony destruction, and sequestrum formation. Pathogenic organisms are normal oral flora, Staphylococcus aureus, and aerobic gram-negative bacilli. Chronic mandibular osteomyelitis must be differentiated from malignant disease involving the mandible. Diagnosis is accomplished by bone biopsy and culture. Treatment involves through surgical debridement and prolonged antimicrobial therapy. Osteoradionecrosis of the mandible is extremely recalcitrant to conventional therapy, but aggressive surgery and treatment have proven effective.

Actinomycosis. Surgical aspects.

Actinomycosis is an anaerobic infection caused by actinomycetes, which are part of the normal flora in the oral cavity and intestine. Antecedent disease or surgery predisposes to infection, and involved tissue becomes indurated and forms multiple draining fistulae discharging characteristic sulfur granules. Three principal clinical syndromes are described: cervicofacial, thoracic, and abdominal. Recently pelvic actinomycosis has become more prevalent and associated with women who use the intrauterine device. The diagnosis of actinomycosis usually is made at surgery. Biopsied material histologically demonstrates sulfur granules and filamentous gram-positive rods. The differential diagnosis includes cancer and other chronic infections. Treatment consists of appropriate antimicrobial therapy and often surgery including incision and drainage or excision of abscesses, drainage of empyemas, and removal of persistent sinuses.

Reactivity of serum-armed xenogeneic macrophages to breast cancer antigens.

Sera from breast cancer patients contained cytophilic antibody which armed guinea pig peritoneal macrophages. These macrophages then exhibited specific adherence inhibition in the presence of tissue culture tumor antigens. These antigens were obtained from primary cultures of autologous or allogeneic breast cancer cells. Sera from control subjects for the most part did not induce macrophage adherence inhibition in the presence of these same antigens.

Bacteremia and bacteriuria after transrectal prostatic biopsy.

To determine the efficacy of parenteral gentamicin versus povidone-iodine enema (P.I.E.) in preventing infectious complications, a randomized study was undertaken in 40 patients undergoing transrectal needle prostatic biopsy. In 69 per cent of patients not receiving P.I.E. bacteremia developed, and 32 per cent acquired bacteriuria; whereas only 19 per cent of patients given P.I.E. alone or in combination with gentamicin because bacteremic, and 9.5 per cent had postbiopsy bacteriuria. Thus, P.I.E. provided a safe and effective means for preventing most bacteremia and bacteriuria associated with transrectal biopsy of the prostate.

Lymphocyte transformation for the detection of herpesvirus-induced tumor-associated antigens.

Cell-mediated immunity to fibroblasts transformed by herpes simplex virus type 2 was investigated with a lymphocyte assay system. The assay system was first standardized with phytohemagglutinin, a nonspecific stimulator of blastogenesis. Hamster splenic and blood lymphocytes reacted to phytohemagglutinin with a dose-response curve similar to that reported for other rodent species. Splenic lymphocytes from hamsters bearing isografts, induced by herpes simplex virus type 2, were transformed by cell-free virus-induced tumor antigens. The reactions with cell-free tumor antigens were dose-dependent and paralleled the findings with phytohemagglutinin. The initial transformation response of immune lymphocytes to homologous tumor antigens occurred after 72 hr incubation with antigen. Immune splenic lymphocytes from hamsters were also significantly stimulated with antigens obtained from cells productively infected with herpes simplex virus type 2. Immune lymphocytes were not stimulated with heterologous antigens from simian virus 40-transformed mouse or hamster cells. Likewise, lymphocytes from hamsters sensitized to cells transformed by simian virus 40 reacted with both simian virus 40-transformed mouse and hamster cells but did not react with cells transformed by a heterologous virus. The results suggest that under defined conditions a lymphocyte transformation assay may be useful for the specific detection of common viral-induced antigens on tumor cells.

Anaerobic septicemia after transrectal prostatic biopsy.

Transrectal biopsy of the prostate resulted in anaerobic septicemia in two patients, despite parenteral gentamicin sulfate prophylaxis. Bacteroides fragilis sepsis developed subacutely in one patient having a postbiopsy pelvic abscess. Clostridium perfringens sepsis occurred fulminantly in another patient 24 hours after biopsy of a gland extensively involved with adenocarcinoma. These cases indicate a potential hazard of sepsis due to anaerobic contamination with rectal microflora at the time of transrectal prostatic biopsy and the futility of prophylaxis directed only at aerobic bacteria.