Evidence of fungal decay in petrified legume wood from the Neogene of the Bengal Basin, India.

Silicified fossil legume woods of Cynometroxylon Chowdhury & Ghosh collected from the Neogene (late Miocene) sediments of the Bengal Basin, eastern India, exhibit fungal decay seldom found in the fossil record. The wood possesses numerous perforate areas on the surface that seem to be the result of extensive fungal activity. In transverse section, the decayed areas (pockets) appear irregular to ellipsoidal in outline; in longitudinal section these areas of disrupted tissue are somewhat spindle-shaped. Individual pockets are randomly scattered throughout the secondary xylem or are restricted to a narrow zone. The aforesaid patterns of decay in fossil wood show similarities with that of white rot decay commonly produced by higher fungi, specifically basidiomycetes and ascomycetes. The host fossil wood harbors abundant ramifying and septate fungal hyphae with knob like swellings similar to pseudoclamps in basidiomycetes, and three-celled conidia-like reproductive structures. This record expands our current knowledge of wood decaying fungi-host plant interaction in the Neogene tropical forests of Peninsular India.

Sequence analysis of an immunogenic and neutralizing domain of the human T-cell lymphoma/leukemia virus type I gp46 surface membrane protein among various primate T-cell lymphoma/leukemia virus isolates including those from a patient with both HTLV-I-associated myelopathy and adult T-cell leukemia.

Human T-cell lymphoma/leukemia virus type I (HTLV-I) causes adult T-cell leukemia/lymphoma and HTLV-I-associated myelopathy. Specific regions within the outer envelope proteins of other retroviruses, e.g., human immunodeficiency virus type 1, are highly immunogenic and, because of the selective pressure of the host immune system, quite variable. Mutations in the external envelope protein gene of murine retroviruses and human immunodeficiency virus type 1 influence cellular tropism and disease pathogenesis. By contrast, no disease-specific viral mutations have been identified in HTLV-I-infected patients. However, all isolates studied thus far have originated from leukemic cell lines, peripheral blood mononuclear cells, or cerebrospinal fluid lymphocytes from patients with HTLV-I-associated myelopathy and adult T-cell leukemia/lymphoma and, therefore, may not truly reflect tissue-associated variation. The midregion of the HTLV-I gp46 external envelope glycoprotein (amino acids 190-209) induces an antibody response in 90% of infected individuals, and a hexapeptide in this region (amino acids 191-196) elicits antibodies in rabbits which inhibit syncytia formation and infection of target lymphocytes. Because of the above, we expected the neutralizing domain of the gp46 env gene of HTLV-I to possess disease or organ-associated mutations selected by the infected host's immune system. Hence, we amplified, cloned, and sequenced HTLV-I DNA directly from in vivo central nervous system, spleen, and kidney specimens, and a leukemic cell line from a patient (M. J.) with both HTLV-I-associated myelopathy and adult T-cell leukemia/lymphoma to discern the possibility of tissue- and/or disease-specific variants. In addition, we sequenced several HTLV-I isolates from different regions of the world, including Papua New Guinea, Bellona, and Liberia, and compared them to other previously published HTLV-I and related retroviral sequences. The 239-base pair sequence corresponding to amino acids 178 to 256 in gp46 displayed minor tissue-specific variation in clones derived from central nervous system tissues from patient M. J., but overall was highly conserved at both the DNA and amino acid levels. Variation was observed in this region among the other HTLV-I, simian T-cell lymphoma virus type I, and HTLV-II isolates in a pattern that was consistent with their known phylogenetic relationship. No consistent disease-related changes were observed.(ABSTRACT TRUNCATED AT 400 WORDS)

Purpura fulminans.

Purpura fulminans is a rare disease characterized by cutaneous ecchymosis, hypotension and fever associated with disseminated intravascular coagulation. It usually follows a preparatory infectious illness. A case in a 55 year old woman challenges the concept that this disease is limited to childhood. A review of 100 case reports is presented in which the often quoted high mortality of 90 per cent is found to be no longer tenable.

Reverse transcription takes place within extracellular HIV-1 virions: potential biological significance.

Extracellular HIV-1 virions purified from cell culture supernatants have been found to contain viral DNA that is the result of partial reverse transcription within the virus particles. Our data supported these observations and further indicated that the ratio of genomic RNA to viral DNA was approximately 10(3):1 for the "strong stop" (R-U5) region and 10(5):1 for the gag region. We have shown that, in the absence of detergent, large amounts of DNase-resistant viral DNA can be synthesized within intact HIV-1 virions, indicating that this phenomenon is not dependent on perturbation of the viral envelope. Nascent viral DNA synthesis also occurred in purified virions incubated at 37 degrees C in cell-free human physiological fluids including seminal plasma, blood plasma, breast milk, and fecal fluid. In vitro HIV-1 infection assays, in which HIV-1 DNA synthesis was initiated in HIV-1 virions by prior incubation with deoxyribonucleoside triphosphates, demonstrated that virus particles so treated had an increased infectious titer over untreated virions when incubated with target human T cells. Our data suggest that HIV-1 virion-associated DNA synthesis may occur in vivo and may impact on the efficiency of intra- and interhost virus transmission. If so, this phenomenon should prove to be an important target for antiviral therapeutic strategies.

Management of full-thickness burns of the scalp and skull.

Full-thickness burn injury of the scalp, with or without necrosis of underlying bone, is a complex therapeutic problem. Inability to diagnose depth of injury, controversy regarding wound closure, and a high incidence of acute morbidity are all associated with it. We reviewed the records of 17 patients who had suffered such injury. Wound closure was accomplished by split-thickness autograft alone in three patients, by bone dermabrasion and split-thickness autograft in six, by bone excision and split-thickness autograft in five, and by immediate local rotation flap in three. Systemic and/or local septic complications developed in 50% of all patients who underwent bony debridement. When feasible, early excision followed by immediate flap coverage is the procedure of choice. It avoids the multiple operative procedures required by the more conservative approach to wound closure, thereby shortening the period of primary hospitalization and virtually eliminating the risk of sepsis.

Design and use of signature primers to detect carry-over of amplified material.

Signature primer pairs designed for use with the polymerase chain reaction have been developed which can determine if a positive result originated from the intended target nucleic acid or from so-called "carry-over" contamination of previously amplified DNA. The 3' ends of each signature primer, SK339/341, SSK110/111, and SSK58/59 contain a viral specific sequence complementary to regions of either HIV-1, HTLV-I and II respectively. The 5' ends of each primer contain a non-human, non-viral (NHNV) signature sequence including restriction endonuclease sites for subsequent cloning. A fourth set of primers, SK338/340, consist solely of these NHNV sequences and are designed to anneal to any product previously amplified by the viral-specific signature primers. These primers were tested against their corresponding positive and negative DNA targets, to determine their specificity and sensitivity. As expected, the viral-specific signature primers detected the retroviral infected samples while no detectable amplification occurred in negative DNA controls. Primers SK338/340 did not amplify any viral positive or negative template DNA's. Samples spiked with amplified material generated from the viral-specific signature primers could be specifically amplified by the NHNV primers SK338/340. Primers SK338/340 were determined to be more sensitive than the viral-specific signature primers, ensuring the detection of extremely low amounts of carryover. This strategy may be useful in developing other retroviral or non-retroviral primers with a built-in signature sequence that can differentiate false positives from true positives in a subsequent confirmatory test.

Management of open tibial fractures.

A prospective study was undertaken to accurately classify open tibial fractures and to evaluate the benefit of muscle flaps in the management of these injuries. From 191 open tibial fractures, 59 type III and 14 type IV open fractures were identified and managed prospectively. Fractures managed with open-wound techniques have a much higher complication rate than those closed with flaps. Results with flap coverage are affected by the biologic phase of the wound. The best results are seen in the acute flap coverage group and are thought to be secondary to removal of devitalized tissue with provision of a vascularized soft-tissue envelope prior to wound colonization. Flap coverage of the colonized subacute wound is subject to invasive infection with additional tissue loss. The subacute wound should be managed with open-wound technique until the parameters of a chronic localized wound are established, at which time flap coverage is again indicated. Microvascular free flaps are the preferred cover for type IV wounds because the local tissues are too ischemic and devitalized for transfer. With meticulous wound care and adherence to the enumerated surgical procedures, limb salvage may be achieved in most injuries.

Head and neck reconstruction with the latissimus dorsi myocutaneous flap: anatomic observations and report of 60 cases.

The latissimus dorsi myocutaneous flap can be employed successfully in head and neck reconstruction when the size or nature of the defect precludes the use of local or regional flaps. Generous amounts of hairless skin and muscle may be transferred in one operative procedure while producing an acceptable donor defect. Certain measures may be taken to enhance dependability of the flap and minimize complications, and these are discussed. The Doppler flowmeter is helpful in ascertaining patency of the main-flap vessels preoperatively as well as in identifying specific cutaneous perforators for accurate placement of the island. Locating the paddle two-thirds of the way down the muscle ensures adequate blood supply and sufficient pedicle length for most defects between the thoracic outlet and the roof of the orbits.

Group sex in gay men: its meaning and HIV prevention implications.

HIV/AIDS continues to pose a serious health hazard for gay men. Large numbers of men continue to become HIV infected each year, despite access to knowledge concerning how HIV is transmitted. Although gay men changed their sexual practices early in the epidemic, there is growing concern that there is a resurgence of risky sexual activities occurring in this group. Of particular concern is the resurgence of group sex activities. The purpose of this study was to explore the experiences of group sex in gay men to gain insight into the meaning of group sex to these men, the context in which it occurs, and men's views of how group sexual encounters relate to HIV transmission. The study used a qualitative approach to data collection. Ten self-identified gay men who reported engaging in group sex activities were interviewed concerning their experiences. Men reported that the most likely place for them to engage in group sex activities was in sex clubs, and a majority of their discussions centered on these clubs. Study data were analyzed using content analysis. Two overall categories of responses emerged from men's descriptions of their group sex experience: sexual desire and HIV/STD risk behaviors. Four themes--access to sex, sexual excitement or stimulation, sexual options, and control and sexual freedom--comprised the category of Sexual Desire. The themes identified within the category of HIV/STD risk behaviors included reframing risk, rejection of safer sex, and alcohol and drug use. The findings of the study suggest that sex in group settings such as sex clubs is a reality that must be addressed by HIV prevention efforts. Additionally, results indicate that current HIV prevention messages are being rejected by many gay men and need to be reevaluated for relevance two decades into the HIV/AIDS epidemic.

Nursing education and HIV disease: a call for action.

The continued increase in reported cases of HIV disease has created a compelling need for nursing educators to provide students with comprehensive information on HIV-related issues. The authors discuss the need for students to care for HIV-positive individuals under faculty supervision to overcome fear and anxiety. Faculty education is proposed as a first step to develop a comprehensive approach to HIV education. A guide for integrating HIV content into the curriculum is provided.

Techniques of facial lesion excision and closure.

The goals of facial lesion excision and closure are to minimize scar formation and to camouflage the unavoidable. The extent and quality of the scar depend upon the patient's age and heredity, the exact location of the lesion, and the degree of inflammation. Of these, only the inflammatory response can be controlled. Scarring may be reduced by keeping inflammation to a minimum through atraumatic tissue handling, absolute hemostasis, suture placement to avoid strangulation, and early removal of skin sutures. When these plastic surgical maxims are followed, and if the incision is placed correctly, the final scar will be nearly invisible.

Moderate hemophilia B Leyden: identification by polymerase chain reaction, sequencing, and oligomer restriction.

Hemophilia B Leyden is a rare form of congenital factor IX deficiency which is characterized by severe factor IX deficiency at birth, which ameliorates after puberty. It is caused by mutations in the factor IX gene promoter region and the postpubertal amelioration is thought to be mediated by the action of testosterone on an androgen response element located in the promoter region. Three kindreds have been previously reported with a milder form of hemophilia B Leyden, associated with a guanine to adenine transition at nucleotide position -6 of the promoter region. We now report a fourth kindred with this mutation. The proband was a newborn with a factor IX level of 2.5%, his 12-year-old half-brother had a level of 28%, and his mother's 56-year-old maternal cousin had a level of 60%. A G to A transition at nucleotide -6 of the promoter region was demonstrated by cloning and sequencing polymerase chain reaction products from the half brother, and the mother was demonstrated to be a carrier. The mutation eliminates a TaqI restriction endonuclease site normally present in the wild type promoter, and the mother's cousin was demonstrated to carry the mutation by the absence of digestion with TaqI. The identification of hemophilia B Leyden with this specific mutation has practical importance to the clinical management because of its unique natural history and significantly better prognosis than classical hemophilia B.

Face burn reconstruction--does early excision and autografting improve aesthetic appearance?

Despite improvements in functional rehabilitation secondary to better control of scar and contractures, aesthetic rehabilitation of the extensively burned face has remained a difficult problem. This study was undertaken to evaluate both technique and aesthetic results of early excision and split thickness autografting (STAG) of full skin thickness face burns. Twenty-five patients with full skin thickness face burns were operated on between days 4 and 14 post-burn. Thirteen patients had excision and STAG in one stage. Twelve patients had a two-stage procedure-excision and coverage with a biological dressing followed 24-72 h later by STAG. Seven of these patients had a pressure dressing in the form of a silicone face mask applied at the second stage. Early cosmetic results were encouraging in all patients. Twenty-five per cent of patients later required either contracture release or skin resurfacing. Preliminary results are encouraging and warrant evaluation by surgeons at other centres. When early excision of full skin thickness face burns is undertaken, cautious optimism as to the ultimate aesthetic result, both by the surgeon and the patient, is advisable.

Nascent human immunodeficiency virus type 1 reverse transcription occurs within an enveloped particle.

Although a small amount of viral DNA has been shown to be enclosed within human immunodeficiency virus type 1 (HIV-1) virions, the majority of full-length viral DNA is formed after this virus infects target cells. Hence, we undertook investigations to identify the physical characteristics of the HIV-1 replication unit during the early events of infection. In these studies, nascent viral DNA synthesis was found to occur between 15 and 30 min after purified, DNase-treated HIV-1 virions were added to HUT 78 cells. At 1 h postinfection, a large amount of strong-stop viral DNA and some first-strand viral DNA had been synthesized. Several lines of evidence, including purification, nuclease digestion, and immunoprecipitation, indicated that these nascent viral DNAs were located within particles containing components such as reverse transcriptase and p24gag and gp120env proteins and having physical characteristics similar to those of intact virions.

Degenerate and specific PCR assays for the detection of bovine leukaemia virus and primate T cell leukaemia/lymphoma virus pol DNA and RNA: phylogenetic comparisons of amplified sequences from cattle and primates from around the world.

Degenerate and specific PCR assays were developed for bovine leukaemia virus (BLV) and/or primate T cell leukaemia/lymphoma viruses (PTLV). The degenerate assays detected all major variants of the BLV/PTLV genus at a sensitivity of 10-100 copies of input DNA; the specific systems detected 1-10 copies of input target. Sensitivity was 100% in specific DNA-PCR assays done on peripheral blood from seropositive BLV-infected cattle and HTLV-I- or HTLV-II-infected humans, and 62% in RNA/DNA-PCR assays on sera from BLV seropositive cattle. The pol fragments from 21 different BLV strains, isolated from cattle in North and Central America, were cloned and sequenced, and compared to other published BLV and PTLV pol sequences. BLV and PTLV sequences differed by 42%. Sequence divergence was up to 6% among the BLV strains, and up to 36% among the PTLV strains (with PTLV-I and PTLV-II differing among themselves by 15% and 8%, respectively). Some cows were infected with several BLV strains. Among retroviruses, BLV and PTLV sequences formed a distinct clade. The data support the interpretation that BLV and PTLV evolved from a common ancestor many millennia ago, and some considerable time before the PTLV-I and PTLV-II strains diverged from each other. The dissemination of the BLV strains studied probably resulted from the export of European cattle throughout the world over the last 500 years. The relatively similar mutation rates of BLV and PTLV, after their various points of divergence, suggest that there could be a much wider genetic range of BLV than has currently been defined.

Thermo-expandable intraprostatic stents in bladder outlet obstruction: an 8-year study.

OBJECTIVE: To assess the use of a thermo-expandable intraprostatic stent (Memokath(R), Engineers and Doctors A/S, Copenhagen, Denmark) for bladder outlet obstruction in men unable to undergo transurethral resection of the prostate (TURP), assessing symptoms, complications and duration of stent life. PATIENTS AND METHODS: The Memokath stent is a coil of a nickel-titanium alloy which has 'shape memory', the lower end expanding when heated to 55 degrees C. Risks associated with inserting the stent with a flexible cystoscope under local anaesthesia are minimal. Men were selected who were either permanently or temporarily unfit for TURP. Indications included severe respiratory and cardiovascular disease. Exclusion criteria included bladder carcinoma, calculi or detrusor failure; in all, 211 men were fitted with 217 intraprostatic stents over 8 years. RESULTS: There were 1511 TURPs during the study period; the mean age of men receiving a stent was 80.2 years, compared with 70.2 years for those undergoing TURP. The International Prostate Symptom Score decreased from a mean of 20.3 to 8.2 (P < 0.001) in the first 3 months after stent placement; there was virtually no change over 7 years. During the follow-up, 38% of men died with their stents in situ, 34% remain alive, 23% have had their stents removed for failure and 4% were removed as they were no longer required. There was a 13% migration rate and 16% repositioning rate. There were few side-effects (pain 3%, haematuria 3%, incontinence 6% and infection 6%). These frail men were more likely to die than have their stent fail. CONCLUSION: The Memokath intraprostatic stent is a valuable addition to the armamentarium of the urologist treating elderly or frail men with advanced bladder outlet obstruction and complements existing technologies.

Serological and nucleic acid analyses for HIV and HTLV infection on archival human plasma samples from Zaire.

In order to better understand the genomic diversity and molecular phylogeny of the human retroviruses, the plasmas from 250 Zairean patients collected in 1969 were tested for antibodies to human T-cell lymphoma and human immunodeficiency viruses (HTLV or HIV) using ELISA and confirmatory Western blots and for viral nucleic acids by reverse transcriptase-directed PCR (RT-PCR). Interestingly, none of the patients was confirmed positive for HIV, even though this region is now endemic for HIV-1. However, 74 (30%) and 3 (1%) of the samples were positive for antibodies to HTLV-I and II, respectively. Forty-four of 74 (59%) Western blot-positive Zairean samples were RT-PCR positive for HTLV-I, while 1 of 3 (33%) of HTLV-II-seropositive samples was RT-PCR positive. On the contrary, none of the Western blot-negative or indeterminate samples were RT-PCR positive for either HTLV-I or HTLV-II. We have cloned and sequenced 140 bp of the pol gene flanked by SK110/SK111 from 8 HTLV-I- and 1 HTLV-II-positive archival samples from Zaire. The HTLV-I isolates from Zaire cluster together as a phylogenetic group, diverging from the prototype Japanese HTLV-I (ATK) by a range of 1.4 to 3.6%. Their close homology to some African STLV-I isolates suggests relatively recent interspecies transmission. The Zairean HTLV-II isolate is closely grouped with the HTLV-II substrain of isolates found in Paleo-Amerindians of the New World, making it unlikely that it represents an endemic African strain.

Reversal of experimental allergic encephalomyelitis with non-mitogenic, non-depleting anti-CD3 mAb therapy with a preferential effect on T(h)1 cells that is augmented by IL-4.

This study examined whether therapy with a non-mitogenic, non-activating anti-CD3 mAb (G4.18) alone, or in combination with the T(h)2 cytokines, could inhibit induction or facilitate recovery from experimental allergic encephalomyelitis (EAE) in Lewis rats. G4.18, but not rIL-4, rIL-5 or anti-IL-4 mAb, reduced the severity and accelerated recovery from active EAE. A combination of rIL-4 with G4.18 was more effective than G4.18 alone. The infiltrate of CD4(+) and CD8(+) T cells, B cells, dendritic cells, and macrophages in the brain stem was less with combined G4.18 and IL-4 than G4.18 therapy or no treatment. Residual cells had preferential sparing of T(r)1 cytokines IL-5 and transforming growth factor-beta with loss of T(h)1 markers IL-2, IFN-gamma and IL-12Rbeta2, and the T(h)2 cytokine IL-4 as well as macrophage cytokines IL-10 and tumor necrosis factor-alpha. Lymph nodes draining the site of immunization had less mRNA for T(h)1 cytokines, but T(h)2 and T(r)1 cytokine expression was spared. Treatment with G4.18, rIL-4 or rIL-5 from the time of immunization had no effect on the course of active EAE. MRC OX-81, a mAb that blocks IL-4, delayed onset by 2 days, but had no effect on severity of active EAE. G4.18 also inhibited the ability of activated T cells from rats with active EAE to transfer passive EAE. This study demonstrated that T cell-mediated inflammation was rapidly reversed by a non-activating anti-CD3 mAb that blocked effector T(h)1 cells, and spared cells expressing T(h)2 and T(r)1 cytokines.