The gene expression of human foamy virus does not require a post-transcriptional transactivator

Human foamy virus (HFV) comprises a complex genomic organization of gag, pol, env, and several nonstructural genes such as bel1, bel2, bel3, bet, beo, and bes located between env and 3' LTR. Among these viral nonstructural genes, bel1 appears to encode an essential transactivator of LTR-directed gene expression. To investigate the roles of the other nonstructural proteins for the viral replication, a series of proviral mutants were generated and tested for their in vitro replication. The mutations in the other than bel1 open reading frame did not show any significant effect on viral replication. The bel1 protein is the only essential transactivator for the LTR-directed transcription. To determine whether HFV has an essential post-transcriptional transactivator like the rev protein of human immunodeficiency virus type 1, or the rex protein of human T cell leukemia virus type 1, we investigated the bel1-independent expression of the HFV gag structural gene under the control of the heterologous simian virus 40 promoter. We demonstrated that the expression of the HFV gag structural gene does not require an essential post-transcriptional transactivator. Thus, it appears that the regulation of HFV gene expression is distinct from that of other human retroviruses.

Microwave antigen retrieval in immunocytochemistry: a study of 80 antibodies

AIMS

To evaluate the effect of microwave irradiation on the staining quality of a range of commonly used primary antibodies in archival, formalin fixed, paraffin wax embedded material, with emphasis on antibodies that have previously worked successfully only on frozen tissue.

METHODS

Immunocytochemistry (streptavidin-biotin complex technique) was performed on histological sections of a range of normal and pathological tissues, after varying treatment with microwave irradiation. The staining quality of each antibody was compared with that achieved without prior treatment of the sections or after enzyme predigestion.

RESULTS

Microwave irradiation permitted successful immunostaining with 20 antibodies that stained only frozen tissues before. The staining characteristics of 21 antibodies that were already known to stain formalin fixed, paraffin wax embedded material were improved. Another 39 antibodies did not show enhanced staining with microwave irradiation. The method preserves tissue morphology and produces more consistent staining than that achieved by enzyme predigestion with many antibodies. Microwave irradiation may also allow some primary antibodies to be used at higher working dilutions. The citrate buffer used in this study avoids the necessity of exposure to heavy metal salts.

CONCLUSIONS

Microwave antigen retrieval represents an important technical advance within immunocytochemistry that will greatly increase the range of antibodies which can be used to study formalin fixed, paraffin wax embedded tissues.

Pagetoid spread into the rete testis by testicular tumours

Germ cell neoplasia of the testis can spread into the rete testis in a pagetoid manner, but this is less often recognized than vascular invasion or direct spread into the tunica albuginea. The rete testis was studied in 71 orchidectomy specimens: 47 with an untreated germ cell tumour, 18 with germ cell neoplasia after treatment with chemotherapy, and six with other tumours. Pagetoid spread into the rete testis was seen in 14 of the 47 cases of germ cell tumour. The cytology of the infiltrating cells was that of intratubular germ cell neoplasia. Hyperplasia of the rete testis was seen in six cases. In three of the four testes with untreated germ cell neoplasia and hyperplasia of the rete, neoplastic cells were seen in the hyperplastic rete epithelium. The two testes with extensive pagetoid involvement of the rete testis by intratubular germ cell neoplasia both had associated hyperplasia of the rete testis. Two of the 18 testes with germ cell neoplasia after chemotherapy had focal hyperplasia. Pagetoid involvement of the rete testis by intratubular germ cell neoplasia is common and may be a cause of hyperplasia of the rete testis.

Osteoporosis and bone morbidity in cardiac transplant recipients

PURPOSE

To evaluate the incidence and etiology of osteopenia and pathologic fractures in cardiac transplant recipients.

PATIENTS

Thirty-one adult male cardiac transplant recipients and 14 adult men with congestive heart failure (CHF) awaiting cardiac transplantation.

METHODS

Assessment of indices of bone and mineral metabolism and of bone mineral density (BMD) by dual-energy x-ray absorptiometry.

RESULTS

BMD in the proximal femur was below normal in both groups compared to that in age-matched control subjects, whereas BMD in the lumbar spine was normal. There was no significant difference in BMD at any site between the two groups. No clinical parameter predicted BMD. In all patients, laboratory indices of bone mineral metabolism, except parathyroid hormone (PTH) levels, were normal and not statistically different between the two groups. CHF patients had a trend toward elevations of PTH, 1,25-dihydroxyvitamin D, and urinary calcium excretion compared to transplant patients. Eight of 31 transplant patients and 2 of 14 CHF patients had vertebral compression fractures (c2 = 11.8, p < 0.0006). Transplant recipients with fractures had twice as many rejection episodes as did transplant patients without fractures, but did not differ in cumulative dose of steroids. Two patients developed avascular necrosis of the femoral head following transplantation.

CONCLUSIONS

Cardiac transplant recipients and patients with CHF awaiting transplantation had decreased hip BMD, but normal spine BMD. Although immunosuppressive therapy did not appear to influence bone mass, loop diuretics prior to transplantation may have stimulated a mild secondary increase in PTH that could have differentially caused loss of bone density at the hip in both groups. Pulse corticosteroids used in treating rejection may have contributed to the increased incidence of vertebral fractures in transplant patients. These data suggest that severe CHF with its associated diuretic use and decreased activity are primary contributors to osteopenia in these patients.

Liver transplantation for patients with alcoholism and end-stage liver disease

Liver transplantation for alcoholic cirrhosis remains controversial. In particular, criteria for the selection of patients who will remain recovered from alcoholism post-transplant require better definition. We analyzed the long-term predictive value of categorizing transplant referral patients with alcoholism and end-stage liver disease into risk groups for recidivism and noncompliance. Forty-seven patients with the diagnosis of alcoholism and advanced liver disease were evaluated and placed into predefined risk groups (low-, moderate-, and high-risk) for recidivism and noncompliance. No absolute period of abstinence from alcohol was required. All patients were asked to sign a contract not to drink alcohol and comply with a rehabilitation program before and after transplantation. Compliance with alcohol rehabilitation, abstinence, functional level, employment, and survival were assessed. Patients who were not compliant with the rehabilitation program or consumed alcohol were scored as failures. Thirty-one patients were ranked as low risk, and were accepted for liver transplantation; 27 patients were transplanted. Five of 31 patients (16%) drank alcohol. One patient drank before and four patients drank transiently after transplantation. Ten patients were categorized as moderate risk, and were deferred for transplantation; two patients underwent later transplantation. All 10 patients (100%) were noncompliant or drank alcohol, including two patients who drank after transplantation after a period of abstinence and rehabilitation. Six patients were ranked as high risk, and were denied liver transplantation. Five patients (83%) drank alcohol and were noncompliant. Minimum follow-up was 12 months (mean, 24 months; range, 12-41 months). The mean Karnofsky performance score was 34 before and 84 after liver transplantation. Actuarial survival of alcoholic patients undergoing transplantation was 93%. We conclude that categorization of transplant referral patients with alcoholism and liver failure into predefined risk groups for recidivism and noncompliance accurately predicts pre- and post-transplant behavior. As defined, only low-risk alcoholic patients are good candidates for liver transplantation.

Multiple positive and negative cis-acting elements that mediate transactivation by bel1 in the long terminal repeat of human foamy virus

The bel1 protein of human foamy virus (HFV), a retrovirus, regulates expression of the gene linked to the HFV long terminal repeat (LTR) and is essential for viral gene expression. The mechanism of action of the bel1 protein is unknown, but its action is mediated through the U3 region of the LTR. To determine which U3 sequences are critical for transactivation by bel1, a series of hybrid vectors consisting of a mutant HFV LTR and the chloramphenicol acetyltransferase gene were constructed and tested for their responsiveness to the bel1 protein by using transient assays after transfection. The target sequences for transactivation by bel1 were mapped to five regions in the U3 domain of the LTR: nucleotides -559 to -506, -454 to -418, -360 to -342, -327 to -284, and -116 to -89 (+1 represents the transcription initiation site). No significant sequence similarity was identified among the five target sites. The observation that the multiple distinct elements in the HFV LTR are the targets for bel1 transactivation is different from observations with other human retroviral systems. The regulation mechanism of HFV bel1 protein-mediated transactivation appears to be analogous to that of some DNA virus transactivators that increase transcription from numerous different viral promoters with little sequence similarity shared among them. We demonstrated that multiple bel1-responsive elements (BRE) can act as bel1-dependent enhancer elements, while a single copy of one BRE, BREe, can serve as an upstream activating element in both orientations. In addition, the region between -466 and -498 was identified as responsible for the downregulation of gene expression directed by BREa, which requires its upstream sequence element to act as a bel1-dependent enhancer element in a heterologous promoter.

Hypogammaglobulinemia and rheumatic disease

Primary hypogammaglobulinemia describes a heterogeneous group of immunoglobulin disorders mainly composed of X-linked agammaglobulinemia, common variable immunodeficiency, and selective immunoglobulin (Ig) A deficiency. The most serious problems are related to recurrent infections with high-grade encapsulated bacteria. However, a wide variety of rheumatologic disorders also occur in association with hypogammaglobulinemic states. Septic arthritis with usual bacterial pathogens such as Staphylococcus aureus, and unusual bacteria such as Mycoplasma and Ureaplasma species, have been described in these patients. An aseptic nonerosive polyarticular arthritis that resembles rheumatoid arthritis is seen in 10% to 30% of hypogammaglobulinemic patients. Autoimmune disorders such as immune thrombocytopenic purpura, immune hemolytic anemia, juvenile rheumatoid arthritis, systemic lupus erythematosus, dermatomyositis, Sjögren's syndrome, essential mixed cryoglobulinemia, chronic active hepatitis, and sarcoidosis have been reported in hypogammaglobulinemic patients. Finally, to complicate matters, many disease-modifying antirheumatic drugs, including gold, D-penicillamine, sulfasalazine, azathioprine, and cyclophosphamide, cause symptomatic hypogammaglobulinemia in some patients.

Transactivation of human immunodeficiency virus type 1 long terminal repeat-directed gene expression by the human foamy virus bel1 protein requires a specific DNA sequence

Human foamy virus (HFV) encodes the transcriptional transactivator bel1. The bel1 protein transactivates HFV long terminal repeat (LTR)-directed gene expression by recognizing a region in U3. It also transactivates human immunodeficiency virus type 1 (HIV-1) LTR-directed gene expression in transient transfection assays. To identify the specific region in HIV-1 LTR responsible for bel1 action, we examined the effect of bel1 on chloramphenicol acetyltransferase (CAT) gene expression in transfected cells with a series of mutant HIV-1 LTR/CAT plasmids. The region between -158 and -118 from the transcription initiation site, immediately upstream of the core enhancer element, was identified as responsible for the transactivation by bel1. In addition, bel1 transactivated a heterologous promoter when this region was positioned upstream of it in the sense and antisense orientations. Optimal transactivation of the HIV-1 LTR by bel1 did not require an intact TAR sequence, suggesting that the binding of tat to the TAR sequence is not a prerequisite for bel1 function in HIV-1 LTR-directed gene expression. In the region of the HIV-1 LTR that is necessary for the bel1-mediated transactivation, we have found a sequence which is conserved between HIV-1 and HFV. Our results suggest that the bel1 action on HIV-1 seems to be mediated by a specific DNA sequence which is shared by both the HIV-1 LTR and HFV LTR.

Molecular diagnosis of Ureaplasma urealyticum septic arthritis in a patient with hypogammaglobulinemia

OBJECTIVE

We report a hypogammaglobulinemic patient with a destructive oligoarticular arthritis, whose synovial fluid cultures were repeatedly sterile.

METHODS AND RESULTS

We identified a Ureaplasma urealyticum infection in his affected joints, using a polymerase chain reaction (PCR) assay.

CONCLUSION

The PCR technique promises to be extremely valuable in the rapid and specific diagnosis of infectious arthritis.

Gonococcal septic arthritis of the hip

We describe a patient with a Neisseria gonorrhoeae monoarthritis of the hip. Treatment with intravenous ceftriaxone, oral doxycycline, and repeated fluoroscopic needle aspirations resulted in a complete recovery of function without residual deficit. Gonococcal monoarthritis of the hip is rare. Gonococcal hip infections appear to respond well to antibiotics and drainage by arthrocentesis. This differs from hip infections caused by other bacteria where joint damage is common and where the recommended initial treatment is open surgical drainage.

The growing teratoma syndrome

Thirteen patients with metastatic non-seminomatous germ cell tumours and enlarging metastases consisting of teratoma differentiated only were identified. Patients were managed with surgical resection soon after the growing lesions were documented. Surgical morbidity was minimal and 12 patients are alive (10 are disease-free) at a median follow-up of 28 months.

Cartilaginous metaplasia of the epiglottis

Metaplastic elastic cartilaginous tissue has been described in the vocal cord, vestibular fold and ventricle of the larynx. This report documents a case in which cartilaginous metaplasia developed in the soft tissue of the epiglottis following an episode of epiglottitis.

Pituitary adenoma causing classical migraine

A case of pituitary adenoma associated with classical migraine is described. The resolution of symptoms following removal of the tumour suggests a causal link.

Effects of nonadherent dressing materials on the healing of open wounds in dogs

Four types of nonadherent dressing materials (rayon/polyethylene dressing, cotton nonadherent film dressings, fine mesh gauze petrolatum dressings, and commercial petrolatum emulsion dressings) were applied on small full-thickness skin defects on the backs of 12 Beagles. At 7 days, the wounds treated with the petrolatum-containing dressings had more contraction than wounds dressed with cotton nonadherent film dressings and wounds dressed with rayon/polyethylene dressings. However, by days 14 and 21, there was little difference in the amount of contraction of any of the wounds. At 7, 14, and 21 days, the wounds dressed with petrolatum-containing dressings had less epithelialization than wounds dressed with cotton nonadherent film dressings and rayon/polyethylene dressings. The uniform open mesh of the commercial petrolatum emulsion dressings allowed the best absorption of exudate and bacteria into the secondary overlying bandage.

Evaluation of plasma and buffy coat ascorbic acid concentrations in dogs before and after a 24-hour fast

Samples of blood were taken from 15 female and 15 male research laboratory Beagles before and after they were fasted for 24 hours. The mean buffy coat ascorbic acid concentration was significantly higher in dogs after they were fasted than that before they were fasted. In contrast, the mean plasma ascorbic acid concentration was significantly lower in dogs after they were fasted than that before they were fasted. The mean buffy coat ascorbic acid concentrations in blood samples of both fasted and nonfasted female Beagles was significantly greater than those of male Beagles, whereas the mean plasma concentrations of both fasted and nonfasted female Beagles was significantly lower than those of male Beagles. It was observed that whenever there was a decrease in plasma ascorbic acid concentration, there was an increase in buffy coat ascorbic acid concentration, regardless of fasting stress or sex difference.

A newly designed tensiometer

A newly designed tensiometer is described in detail. The tensiometer was used to test the tensile strengths of skin wounds on the trunks of 12 female laboratory Beagles at 5, 9, and 14 days after operation. The tensile strengths increased significantly from day 5 to day 14. The newly designed tensiometer could be used to obtain accurate in vivo measurements of the tensile strengths of skin wounds.

Effects of sympathetic stimulation on the round window compound action potential in the rat

The effect on the ear of stimulating the sympathetic nervous system was studied in rats by recording the compound action potentials (N1N2) in response to 2 kHz tonebursts presented to anesthetized rats before, during, and after electrical stimulation of the superior cervical ganglion, and evaluating the changes in N1 latency which resulted. Stimulation of the superior cervical ganglion was found to cause an increase in the N1 latency which was more pronounced at low stimulus intensities (mean value 0.09 +/- 0.04 ms (S.E.) at 5 dB above threshold) than at moderate stimulation intensities (0.08 +/- 0.04 ms at 15 dB above threshold), with little change in latency occurring at the highest intensity tested (0.02 +/- 0.01 ms at approximately 25-30 dB above threshold). In addition, individual animals varied in their responses to stimulation of the superior cervical ganglion, with some animals evidencing a great change in the latency of the response (0.4 ms increase at 10 dB above threshold) and others showing very little change in latency. This variability could not be related to the condition of the animal at the time of observation of the response. In one of the twelve animals there was a slight decrease in latency as a result of sympathetic stimulation (0.07 ms at 5 dB above threshold), and although not studied systematically, low frequencies seemed to be affected more than high frequencies. Further, the change in the amplitude of N1 was not systematically related to sympathetic stimulation. After the administration of hexamethonium (which blocks transmission in autonomic ganglia) in three rats there was no effect on the latency of the N1 potential from sympathetic stimulation as recorded before sympathetic stimulation.

Spinal-evoked potentials and spinal conduction velocity of the cat: reference values

Spinal conduction velocities of the fastest afferent fibers of the spinal cord were calculated from the onset latencies of averaged evoked responses elicited by stimulation of the tibial nerve sensory afferent fibers and were recorded at various sites on the spinal cord. Locations for stimulation and recording electrodes were identified. Waveforms, mean amplitudes, and duration of the evoked spinal potentials were described. The mean conduction velocity of the spinal cord afferents at T12-T13 was 74.25 m/s with a SD of +/- 9.81 m/s. The mean conduction velocity of the spinal cord afferents, determined at the cisterna magna, was 80.66 m/s with a SD of +/- 11.50 m/s. This is a slight increase over the spinal conduction velocity at T12-T13 (P = 0.05).

Effects of gentamicin solution and cream on the healing of open wounds

When 0.1% gentamicin solution was applied to full-thickness skin wounds of dogs, the wounds became smaller by contraction during the first 7 days and continued to contract over the next 14 days. Wounds treated with 0.1% gentamicin cream enlarged during the first 7 days, followed by wound contraction over the next 14 days. The wounds treated with gentamicin solution also had more epithelialization at 7 days than did the cream-treated wounds; however, epithelialization of the 2 types of wounds was similar at 14 and at 21 days. Gentamicin solution and cream were effective in controlling bacterial growth on wounds when compared with the bacterial growth on the control wounds (not treated with antibiotics).

Selective intracavitary and coronary hypothermic cardioplegia for myocardial preservation.Clinical, physiologic, and ultrastructural evaluation

Intraoperative myocardial protection was evaluated in two groups of patients undergoing coronary surgery in whom different techniques for cardiac arrest were utilized. In group A, profound selective myocardial hypothermic (15 to 18 C) arrest was achieved by perfusing a coolant (7 to 10 C) into the left ventricular cavity and the coronary circulation. The average anoxic arrest time was 82.5 +/- 27 minutes. In group B, ventricular fibrillation and moderate hypothermia were used. Group A patients showed rapid physiologic recovery, low average myocardial creatinine phosphokinase (MB-CK) isoenzyme levels (7.8 IU) , and a well-preserved myocardial ultrastructure. In group B, three patients showed abnormal physiologic recovery; six patients needed postoperative inotropic support; and in seven patients, electron-microscopy revealed irreversible focal changes. The average MB-CK isoenzyme level was 85.6 IU. Analysis of our data demonstrates that when myocardial protection during coronary bypass grafting is achieved by selective profound intracavitary and coronary cooling, there is physiological, ultrastructural, and biochemical evidence of less intraoperative myocardial damage than when ventricular fibrillation is applied.

Distribution of cholinesterases in insects

The study of toxicology and other related fields has been largely based on in vitro techniques. These methods have provided quantitative information on the effects of inhibitors on enzymes, but none on the localized effects of inhibitors on selected sites of action within the animal. Histochemical study of frozen sections does provide data on the site of action of toxicants. The utility of histochemistry in conjunction with in vitro methods is discussed.The substrates acetylthiocholine and phenyl thioacetate were utilized in demonstrating cholinesterase. Neither substrate penetrated well into freshly dissected nerve cord preparations, but both compounds were hydrolysed by sectioned tissue. The leaving group of phenyl thioacetate was demonstrated to be benzenethiol. In general, acetylthiocholine was hydrolysed slightly more rapidly by insect cholinesterases. A unique cholinesterase was found in motor end-plates of cricket muscle, which hydrolyses acetylthiocholine and which was inhibited by physostigmine. No other insect muscle preparation showed this activity. Topical application of insecticides showed that a vital site of action in flies is the peripheral area of the thoracic ganglia and that in crickets the brain and nerve cord are involved at knock-down. Kinetic data indicate that acetylthiocholine has a greater affinity than does phenyl thioacetate for a variety of enzyme sources. Ultrastructural evidence shows that cholinesterases that hydrolyse acetylthiocholine are membrane-bound. Phenyl thioacetate was found to be useful as a model in designing new insecticides.