Hof1 plays a checkpoint-related role in MMS-induced DNA damage response in Candida albicans

Cells depend on robust DNA damage recognition and repair systems to maintain genomic integrity for survival in a mutagenic environment. In the pathogenic yeast Candida albicans, a subset of genes involved in the response to DNA damage-induced genome instability and morphological changes has been found to regulate virulence. To better understand the virulence-linked DNA repair network, we screened for methyl methane sulfonate (MMS) sensitivity within the GRACE conditional expression collection and identified 56 hits. One of these potential DNA damage repair-associated genes, a HOF1 conditional mutant, unexpectedly had a previously characterized function in cytokinesis. Deletion of HOF1 resulted in MMS sensitivity and genome instability, suggesting Hof1 acts in the DNA damage response. By probing genetic interactions with distinct DNA repair pathways, we found that Hof1 is genetically linked to the Rad53 pathway. Furthermore, Hof1 is down-regulated in a Rad53-dependent manner and its importance in the MMS response is reduced when Rad53 is overexpressed or when RAD4 or RAD23 is deleted. Together, this work expands our understanding of the C. albicans DNA repair network and uncovers interplay between the cytokinesis regulator Hof1 and the Rad53-mediated checkpoint.

The small molecule genkwanine M induces single mode, mesenchymal tumor cell motility

Individual tumor cells utilize one of two modes of motility to invade the extracellular matrix, mesenchymal or amoeboid. We have determined that the diterpenoid genkwanine M (GENK) enhances the mesenchymal mode of cell motility that is intrinsic to HT-1080 osteosarcoma cells, stimulates a mesenchymal mode of motility in stationary MDA-MB-453 breast carcinoma cells, and induces a shift to a mesenchymal mode of cell motility in LS174T colorectal adenocarcinoma cells that normally utilize the alternate amoeboid mode of motility. The ability of GENK to stimulate or induce mesenchymal motility was preceded by a rapid cell spreading, elongation and polarization that did not require new gene expression. However, these initial morphologic changes were integrin dependent and they were associated with a reorganization of focal contacts and focal adhesions as well as an activation of the focal adhesion kinase. Therefore, GENK induces a mesenchymal mode of cell motility in a wide variety of tumor cell types that may be mediated, at least in part, by an activation of integrin-associated signaling.

A method to test large numbers of bovine semen samples for viral contamination and results of a study using this method

A procedure to test large numbers of semen samples for viral contamination is described. The procedure has the advantages of being simple to perform, sensitive and a relatively inexpensive method to test pooled semen samples, but it has the disadvantage of requiring serologically negative calves and sheep, isolation facilities to prevent environmental contamination during the testing procedure and relatively long times to obtain results. Using this in vivo procedure called the "Cornell Semen Test", it was found that of 40,000 ejaculates tested during a four year period none contained Infectious Bovine Rhinotracheitis Virus, Bovine Herpes Mammalitis Virus, Bovine Leukemia Virus nor Bluetongue Virus at infectious levels. The only virus that was found in a limited number of pools of semen was Bovine Virus Diarrhea Virus. It is recommended that if large volumes of pooled semen are to be tested for viral contamination that this procedure be used.

Evaluation and characterization of forage Sorghum as feedstock for fermentable sugar production

Sorghum is a tropical grass grown primarily in semiarid and drier parts of the world, especially areas too dry for corn. Sorghum production also leaves about 58 million tons of by-products composed mainly of cellulose, hemicellulose, and lignin. The low lignin content of some forage sorghums such as brown midrib makes them more digestible for ethanol production. Successful use of biomass for biofuel production depends on not only pretreatment methods and efficient processing conditions but also physical and chemical properties of the biomass. In this study, four varieties of forage sorghum (stems and leaves) were characterized and evaluated as feedstock for fermentable sugar production. Fourier transform infrared spectroscopy and X-ray diffraction were used to determine changes in structure and chemical composition of forage sorghum before and after pretreatment and the enzymatic hydrolysis process. Forage sorghums with a low syringyl/guaiacyl ratio in their lignin structure were easy to hydrolyze after pretreatment despite the initial lignin content. Enzymatic hydrolysis was also more effective for forage sorghums with a low crystallinity index and easily transformed crystalline cellulose to amorphous cellulose, despite initial cellulose content. Up to 72% hexose yield and 94% pentose yield were obtained using modified steam explosion with 2% sulfuric acid at 140 degrees C for 30 min and enzymatic hydrolysis with cellulase (15 filter per unit (FPU)/g cellulose) and beta-glucosidase (50 cellobiose units (CBU)/g cellulose).

Characterization of human semen alpha-L-fucosidases

Human semen contains a large amount of alpha-L-fucosidase activity, the great majority of which is found in the seminal fluid. Immunocytochemical studies indicate that a small amount of semen fucosidase activity is present on the sperm plasma membrane, primarily in the posterior head region. Subcellular fractionation studies also indicate that sperm alpha-L-fucosidase is present in the plasma membrane-enriched fraction. Comparative characterization of human seminal fluid and sperm alpha-L-fucosidases indicates that seminal fluid alpha-L-fucosidase has a broad pH optimum curve with a number of near-equal maxima between pH 4.8 and 7.0 while sperm fucosidase has a major optimum between pH 3.4 and 4.0. Isoelectric focusing indicates that seminal fluid alpha-L-fucosidase contains three to six isoforms with isoelectric points (pI) of 5-7 while sperm fucosidase contains two distinct isoforms with pI values of 5. 2 +/- 0.2 and 7.0 +/- 0.2. Western blotting indicates that seminal fluid fucosidase contains a major protein band with a molecular mass ratio (M(r)) of approximately 56 kDa while sperm fucosidase contains a major protein band of approximately 51 kDa. The overall results indicate the presence of a low-abundance, plasma membrane-associated human sperm alpha-L-fucosidase, which is different in its properties from human seminal fluid alpha-L-fucosidase(s), and whose function is not yet known.

Leptin indirectly affects estrous cycles by increasing metabolic fuel oxidation

In previous experiments, lean Syrian hamsters fasted on days 1 and 2 of the estrous cycle failed to show sex behavior and ovulation normally expected to occur on the evening of day 4. The first goal of the present experiment was to determine whether systemic treatment with the ob (obese) protein leptin could reverse the effects of fasting on estrous cyclicity, social behaviors, and ovulation rate. Fasting-induced anestrus was reversed and normal sex and social behavior and ovulation rate were restored in hamsters injected intraperitoneally with 5 mg/kg leptin every 12 h during fasting on days 1 and 2 of the estrous cycle. A second goal was to test whether the effects of leptin could be prevented by treatment with pharmacological agents that block the oxidation of metabolic fuels. Glucose oxidation was blocked by treatment with 2-deoxy-d-glucose (2DG) and fatty acid oxidation was blocked by treatment with methyl palmoxirate (MP). 2DG (1000 mg/kg) or MP (20 mg/kg) was administered at doses that did not induce anestrus in hamsters fed ad libitum. As in the first experiment, fasting-induced anestrus was reversed by leptin treatment. However, when each injection of leptin was preceded by an injection of 2DG or MP, leptin treatment did not reverse fasting-induced anestrus. In summary, estrous cyclicity was not restored when oxidation of metabolic fuels was blocked, despite high endogenous levels of leptin. These results are consistent with the hypothesis that leptin acts indirectly on the reproductive system by increasing fuel oxidation.

A panel of monoclonal antibodies against human sperm

To help identify and characterize antigens involved in sperm functions and immune infertility, monoclonal antibodies (mAbs) were raised against human sperm antigens. The immunoglobulin G (IgG) fraction of serum from a male donor with a spontaneous high titer of IgG-positive antisperm reactivity (as determined by immunobead binding) was purified by ammonium sulfate precipitation. This IgG preparation was coupled to Sepharose 4B and was used for immunoaffinity purification of antigens from a detergent-solubilized extract of pooled normal human sperm. The affinity-purified antigens were used to immunize female mice, and the resultant spleen cells were fused with SP 2/0 mouse myeloma cells to generate hybridomas. A single-step semisolid methylcellulose method was used to isolate hybridomas for the selection of positive clones, which were determined by enzyme-linked immunosorbent assay. Thirty-two positive hybridoma lines were selected for immunolocalization and cross-reactivity studies using an avidin-biotin complex assay. Distinctive staining patterns and distribution of sperm antigens were observed for 10 mAbs. Among them, the cross-reactivity with human lymphocytes was not observed for four mAbs.

Acute lymphatic filariasis in an American traveler

Acute lymphatic filariasis developed in an American traveling recreationally to Asia. The illness was characterized by fatigue, eosinophilia, and lymphedema of the arm and chest wall, but no lymphangitis, lymphadenitis, or pain. Complete resolution occurred over 1-2 years. We discuss this syndrome and describe the use of new diagnostic tests in its diagnosis and management.

Antiviral therapy: current concepts and practices

Drugs capable of inhibiting viruses in vitro were described in the 1950s, but real progress was not made until the 1970s, when agents capable of inhibiting virus-specific enzymes were first identified. The last decade has seen rapid progress in both our understanding of antiviral therapy and the number of antiviral agents on the market. Amantadine and ribavirin are available for treatment of viral respiratory infections. Vidarabine, acyclovir, ganciclovir, and foscarnet are used for systemic treatment of herpesvirus infections, while ophthalmic preparations of idoxuridine, trifluorothymidine, and vidarabine are available for herpes keratitis. For treatment of human immunodeficiency virus infections, zidovudine and didanosine are used. Immunomodulators, such as interferons and colony-stimulating factors, and immunoglobulins are being used increasingly for viral illnesses. While resistance to antiviral drugs has been seen, especially among AIDS patients, it has not become widespread and is being intensely studied. Increasingly, combinations of agents are being used: to achieve synergistic inhibition of viruses, to delay or prevent resistance, and to decrease dosages of toxic drugs. New approaches, such as liposomes carrying antiviral drugs and computer-aided drug design, are exciting and promising prospects for the future.

Characteristics of somatotropin and prolactin profiles in young dairy sires before and after a 72-hour fast during different seasons

Serial blood samples were collected from young (mean = 275 d of age) AI sires at 20-min intervals for an 8-h period before and after a 72-h fast. Samples were collected from four different groups of young sires in January (n = 23), April (n = 31), July (n = 27), and October (n = 24). Samples were collected for only 6 h for the July group. Plasma somatotropin (ST) and prolactin (PRL) data were analyzed by PULSAR, a computerized peak detection program. The PULSAR parameters, except for number of peaks detected, were not different (P greater than .05) when calculated using data from the entire 8-h period or just the first 6 h. Because some endocrine characteristics as defined by PULSAR were influenced by season, deviated values were calculated for those characteristics within seasonal groups by subtracting the mean of that group from each individual observation for all PULSAR parameters. Number of ST peaks was correlated (P less than .01, r = .26) with USDA pedigree index (PI) for fat yield (PIF), sire predicted transmitting ability for fat (PTAF; P less than .01, r = .30), Northeast AI Sire Comparison (NEAISC) PIF (P less than .05, r = 24), and sire PTAF (P less than .01, r = .33). No ST pulsatile characteristics after fasting were correlated (P greater than .05) with PI. Prolactin peak length was negatively related to USDA PIF (P less than .05, r = -.23) before fasting and positively correlated (P less than .05, r = .26) after fasting.(ABSTRACT TRUNCATED AT 250 WORDS)

Somatotropin and prolactin profile characteristics in proven AI dairy sires

Blood samples were collected at 20-min intervals for 8 h from 16 Holstein sires, each of which had U.S. Department of Agriculture (USDA) and Northeast AI Sire Comparison (NEAISC) progeny test evaluation data available. Plasma somatotropin (ST) and prolactin (PRL) concentrations were measured, and resulting endocrine profiles were analyzed by PULSAR, a microcomputer-based hormone peak-detection program. The number of ST peaks during the sampling period was negatively related to USDA Predicted Transmitting Ability (PTA) for fat yield, milk, and fat product value (PTA+), and for milk, fat, and protein product value (PRO+), and ST peak length was negatively related to PTA for protein percentage (PTA %P). Interpeak interval for ST was positively related to NEAISC percentage of Protein Deviation (%P). Prolactin peak length was correlated positively with both USDA PTA %P and NEAISC %P, and peak frequency was correlated positively with NEAISC %P. Interpeak interval for PRL was related positively to NEAISC Milk and Fat Deviations. Area under PRL profile was negatively related (P less than .05) to USDA PTA+ and PRO+, and NEAISC Fat Deviation and Dollars. The results indicated that endocrine traits in mature dairy sires are correlated with genetic merit for economically important production traits and suggested that such profile characteristics may be useful in selecting young sires for progeny testing programs.

Rapid staining for the sperm penetration assay using a bisbenzimide dye

Our rapid staining method, accomplished by adding the vital fluorochrome bisbenzimide (Hoechst 33342) directly into the sperm droplet before fertilization, eases visual interpretation of sperm penetration and decondensation. For both within- and between-experiment comparisons, inclusion of bisbenzimide did not influence the overall SPA score or the progress of sperm-egg interaction. These results suggest that bisbenzimide can be used routinely to facilitate scoring of the SPA.

Cytomegalovirus. An update for primary care physicians

Cytomegalovirus infection is spread in various ways--from mother to fetus or baby, from small children in day-care centers to caregivers and parents, by blood transfusions, by sexual contact. Although the illness is usually inconsequential, congenital infection can have severe consequences, including mental retardation and hearing loss. Dr Bean describes the different aspects of this virus and discusses a promising vaccine that may prevent congenital disease.

Plasma somatotropin and prolactin concentrations in young dairy sires before and after a 24-hour fast

To examine the efficacy of plasma concentrations of bST or prolactin as predictors of expected daughter performance, blood samples were collected from young Holstein sires. Blood samples were collected at 15-min intervals via jugular cannulas from 1000 until 1600 h (d 1), beginning 4 h after morning hay feeding. Bulls were not fed again until after collection of blood samples on d 2. Samples were collected at 15-min intervals from 1000 until 1300 h on d 2. Peak values and frequency of hormonal secretory patterns of each bull were characterized by an iterative process in which values greater than 2 SD from the mean were flagged as peaks and excluded from the subsequent calculation of SD and mean. The process continued until an iteration in which no new peaks were flagged. Imposition of a 24-h fast did not alter mean basal bST or prolactin concentrations, but reduced mean peak and overall concentrations of both hormones. The number of bST peaks on d 1 was inversely related to both USDA and Northeast Artificial Insemination Sire Comparison Pedigree Index for milk yield and both USDA and Northeast Artificial Insemination Sire Comparison sire PD for milk yield, but was positively correlated on d 2 with USDA Pedigree Index for milk yield. Mean peak bST on d 2 was correlated with Northeast Artificial Insemination Sire Comparison Estimated Breeding Value for fat yield and sire USDA PD for fat yield. Prolactin peak frequency on d 1 was negatively related to Northeast Artificial Insemination Sire Comparison Pedigree Index for milk yield and sire PD for fat yield. Difference between mean prolactin on d 1 and 2 was negatively related to Northeast Artificial Insemination Sire Comparison Pedigree Index for milk yield and Estimated Breeding Value for fat yield. Endocrine parameters in young sires may be related to genetic merit for production parameters.

Surveillance for persistent bovine viral diarrhea virus infection in four artificial insemination centers

Four large bovine artificial insemination centers implemented a program of surveillance of resident and newly acquired bulls for persistent bovine viral diarrhea virus infection. Infection was identified in 12 of 1,538 bulls. Several clinical abnormalities, including acute and chronic mucosal disease, were evident among the persistently infected bulls. Semen produced by such bulls consistently contained bovine viral diarrhea virus, and such contamination was not always accompanied by diminished seminal quality. Infected bulls were detected by means of virus isolation tests performed on blood specimens, but not by use of serologic testing. Ten of the 12 persistently infected bulls were results of embryo transfer. Virologic surveillance of breeding herds, artificial insemination and embryo transfer centers, and the cattle trade is necessary to prevent spread of this virus by modern cattle breeding practices. Attention is also necessary to prevent contamination by this virus of the fluids used for recovery, in vitro manipulation, and transfer of bovine embryos.

Continuous infusion of high-dose acyclovir for serious herpesvirus infections

Thirteen patients with herpesvirus infections who were unresponsive to at least 72 h of intermittent acyclovir administration received high-dose continuous infusion. Steady-state concentrations were maintained at between 20 and 98 mumol/liter. Of 12 patients who had continuous infusion for greater than 5 days, 7 (58%) resolved their infections, as determined by clinical and virologic parameters, suggesting that continuous infusion may succeed in some patients who do not respond to conventional therapy.

Therapy of herpes zoster with oral acyclovir

Oral acyclovir therapy for herpes zoster has been studied in double-blind, placebo-controlled trials of two dosages, 400 mg and 800 mg five times per day for 10 days. Compared with placebo recipients, recipients of the high-dosage acyclovir experienced a significantly shortened period of viral shedding, significantly accelerated time to 50 percent scabbing, significantly accelerated time to 50 percent healing, and after two days of therapy, significantly less frequent formation of new lesions. The duration and severity of acute pain were less in acyclovir recipients, with differences in pain severity achieving statistical significance (p = 0.03) between Days 3 and 10 and correlating with the treatment differences in new lesion formation. In studies of the 400 mg five times per day dose schedule, differences between acyclovir and placebo recipients were not significant. In a six-month follow-up of recipients in the higher dosage study, the acyclovir recipients experienced less post-zoster pain than placebo recipients; differences in the prevalence of pain were most significant for the presence of a persistent pain in the first three months of follow-up. Oral acyclovir at these dosages appears to be free of adverse reactions. In summary, oral acyclovir at a dosage of 800 mg five times per day for 10 days for treatment of acute herpes zoster is superior to 400 mg five times per day and favorably alters the course of the disease.

A new antibiotic combination for frozen bovine semen. 2. Evaluation of seminal quality

Amikacin, clindamycin, gentamicin, Linco-Spectin, minocin and tylosin were added individually and in combinations at various concentrations to bovine neat semen and to egg-yolk citrate, egg yolk-tris or heated whole milk extenders (nonglycerol fractions) prior to final processing for freezing to -196 degrees C. After thawing samples, seminal quality was measured by progressive motility and acrosomal integrity evaluations. Studies were performed in parallel with microbiological efficacy studies of Shin et al. (7). The antibiotic combination including gentamicin, tylosin and Linco-Spectin at 500 ug/ml, 100 ug/ml and 300/600 ug/ml, respectively, was not detrimental to seminal quality and, in the parallel studies, was most efficacious in controlling microorganisms potentially present in bovine semen.

A new antibiotic combination for frozen bovine semen, 3. Evaluation of fertility

Field fertility (nonreturn rate) studies were performed independently by three artificial insemination organizations to evaluate bovine semen processed for freezing using the antibiotics gentamicin, tylosin and Linco-Spectin at concentrations of 500 ug, 100 ug, and 300/600 ug, respectively, per milliliter of neat semen and per milliliter of nonglycerol portion of the extender. The antibiotic combination including penicillin, dihydrostreptomycin, polymyxin B sulfate, with/without Linco-Spectin (500 units/ml, 2000 ug/ml, 1000 units/ml and 300/600 ug/ml, respectively) was used as the control treatment. Results indicated no significant effect on seminal quality as measured by field fertility under the conditions of these experiments using heated whole milk or egg yolk-sodium citrate seminal extenders. Use of the new antibiotic combination has been adopted by Certified Semen Services.

Treatment of varicella-zoster virus infections

Effective antiviral therapy is now available for many forms of infection due to varicella-zoster virus. Acyclovir is the most widely prescribed treatment, but the virus is not exquisitely sensitive to this drug, and others are under study. The goals of therapy differ among different kinds of patients and must be considered when designing a treatment program.

Cephalothin clearance of Staphylococcus aureus from two experimental infection sites in the presence and absence of local phagocytic cells

The clearance of Staphylococcus aureus from perforated peritoneal capsules which are accessible to phagocytic cells, and subcutaneous Visking chambers which exclude phagocytes, was studied simultaneously in eight rabbits implanted with both devices. Animals were treated with cephalothin, 100 mg/kg im every 8 h for sixteen doses, beginning 24 h after inoculation of the infection sites with S. aureus (cephalothin MIC 0.125 mg/l, MBC 0.5 mg/l). At the start of cephalothin, subcutaneous chambers contained a higher concentration of S. aureus (8.4 log10 cfu/ml) than peritoneal capsules (6.8 log10 cfu/ml, P less than 0.001). There was a significant bactericidal effect in subcutaneous chambers on both the third and sixth day of treatment (P less than 0.002), whereas in peritoneal capsules this did not occur until day six. The total reduction in bacterial count in subcutaneous chambers (7.0 log10 cfu/ml) was significantly greater than in capsules (4.4 log10 cfu/ml, P less than 0.002). The mean concentration of cephalothin in subcutaneous chambers (10.7 mg/l) was significantly higher than in peritoneal capsules (6.1 mg/l, P less than 0.02), but no difference in in-vitro killing of S. aureus was detected at these concentrations. We conclude that cephalothin clearance of S. aureus from a site accessible to phagocytes was delayed when compared to a phagocyte-inaccessible site.

Avulsion of the bovine prepuce from its attachment to the penile integument during semen collection with an artificial vagina

Avulsion of the prepuce (AP) from the penile integument during intromission into an artificial vagina (AV) is the most common injury involving the penis and prepuce of bulls collected for the production of frozen semen at artificial insemination (AI) centers. We observed clinical cases at two AI centers. Because temporary loss of seminal collections from genetically superior bulls occurs and the possibility of impotency exists, the economical loss from AP is significant. Surgery, rather than a nonsurgical procedure, is the preferred method for repair of AP if the diagnosis occurs on the same day as the injury. After injury, seminal collection is avoided. The bull can then begin a conditioning program prior to returning to a normal semen collection schedule. A specific etiology for AP remains undetermined; however, many variables potentially involved in its occurrence are known. Bulls with good libido following 4 to 5 yr of sexual inactivity are particularly susceptible to AP. No genetic predisposition was observed. At present, we believe that AP is caused by many factors and that implementing preventive measures does help.

Progressive mucocutaneous herpes simplex infection due to acyclovir-resistant virus in an immunocompromised patient: correlation of viral susceptibilities and plasma levels with response to therapy

Rapidly progressive disease due to acyclovir-resistant herpes simplex has not been described. We report such a case and detail successful patient management using viral sensitivities and plasma acyclovir levels to guide therapy. Response was correlated with plasma levels above those inhibiting viral growth by 50% (ID50) in vitro.

Semen fertility--an evaluation system for artificial insemination sires, technicians, herds, and systematic fixed effects

Semen fertility was evaluated on 4478 artificial insemination bulls using 2,007,520 breeding receipts for inseminations to 397,979 Holstein cows between January 1, 1978 and November 1, 1984 using mixed linear model methodology. Bulls differed on average by +/- 3.68% conception. Differences between herd-years ranged from 27.4 to -32.3% conception with an average difference of +/- 8.33%. Within herds, cow parity-service number accounted for the largest variation, ranging from 24.0% to -18.5% conception. June was the best month for conception (1.9) and January the poorest (-2.3), indicating effect of temperature and confinement in winter on estrous detection in the northeastern United States. Cows with intervals between repeat services of 21 d had conception rates 12% higher than intervals between repeat services of 11 d. Effect of month-year of semen collection varied by +/- 1.33% conception. Differences between technicians within years varied by +/- 3.37%. Results of the analysis indicate improved conception on dairy farms can be achieved by improved estrous detection, which is a major component of herd-year and service interval. Other components of the model contributed little to the variance in conception or are uncontrollable by farm management.

Systematic environmental, direct, and service sire effects on conception rate in artificially inseminated Holstein cows

Result of insemination was verified for 329,314 artificial inseminations by 882 service sires to 97,245 Holstein cows in 1,075 herds between May 1970 and December 1983. Estimates of systematic environmental and genetic components of cow and service sire components of conception rate were obtained preliminary to development of a fertility monitoring system. Conception rate was 2.9% higher in stanchion than loose housed herds and 2.3% higher in grade than registered cows. Fall months were superior to winter months, the greatest difference being 6.1% between October and January. Conception rate increased with herd milk production, decreased with both increased cow age, and increased herd size in mature and old cows. Regions and inseminators within regions were highly variable. Conception may be influenced by semen price; however, week day of insemination and duration of semen storage had no effect. Conception rate decreased for semen by bulls 8 yr and older, was lowest for semen harvested in June, but no season of collection effect was detected. No genetic trends for cow and service sire conception rate were found; heritability and repeatability were .08 and .06, respectively. Genetic correlations between cow and service sire conception rate and these components with first lactation production and semen output measures were all near zero. Therefore, the relationship between sire fertility and daughter fertility is near zero.

Evaluation of oral acyclovir therapy

Acyclovir is a specific antiviral agent. The triphosphate form inhibits viral DNA replication by competing for incorporation into the replicating DNA chain or by inhibiting viral DNA polymerase. Cells not infected with herpesvirus are generally unaffected. Oral acyclovir inhibits most herpes simplex virus types 1 and 2, and varicella-zoster virus at concentrations used clinically. Oral acyclovir has an average plasma half-life of three hours and is eliminated primarily by renal mechanisms. Peak plasma concentrations occur 1.5 to 2.5 hours after administration and the oral bioavailability is 15 to 30 percent. Acyclovir distributes into most body tissues, including vesicular fluid and the central nervous system. Oral acyclovir is effective treatment of initial and recurrent genital herpes and can suppress frequently recurring genital herpes in both immunocompetent and immunocompromised patients. It is also effective for acute herpes zoster in the immunocompetent and possibly immunocompromised patient. No role is established in either Epstein-Barr virus or cytomegalovirus infections. Oral acyclovir appears to be effective and relatively safe, nontoxic therapy when administered in doses of 1-4 g/d. Oral acyclovir represents a major therapeutic advance in the treatment of herpesvirus infections.

The contribution of echocardiography to the community practice of cardiology. A prospective study

The utility of echocardiography in a clinical office practice was assessed by prospectively studying 93 patients. Each patient was examined by a cardiologist and a diagnosis and management plan was outlined. An M-mode and 2D echocardiogram was then obtained and interpreted by a second cardiologist without knowledge of the clinical findings. Patients were then categorized as follows: group 1, clinical and echo diagnosis agree, management unchanged (67 patients); group 2, clinical and echo diagnosis agree, management changed (two patients); group 3, clinical and echo diagnosis disagree, management unchanged (16 patients); and group 4, clinical and echo diagnosis disagree, management changed (eight patients). Echocardiography significantly altered management of 11 percent of patients, provided additional important information in 48 percent, and confirmed the clinical impression in 74 percent of patients. It was particularly helpful in determining left ventricular structure and function, valvular anatomy, and in the diagnosis of clinically unsuspected idiopathic hypertrophic subaortic stenosis.

Influenza B: hospital activity during a community epidemic

During a community epidemic of influenza B, surveillance throat cultures for influenza were collected from febrile adult patients and hospital employees on three medical wards to determine the frequency and source of influenza among hospitalized patients. Twenty-five cases of influenza B (18.5% of febrile patients) were identified; no clusters of influenza-like illness occurred. The attack rate on two wards was 4.6%. Peak hospital influenza incidence followed that in the community by 1-2 weeks. Twelve of the cases were community-acquired and 13 were nosocomial. 75% of community-acquired cases had three or more common influenza B symptoms, compared with only 39% of nosocomial cases. A viral etiology of fever was suspected clinically in one-half of the cases, but influenza was specifically suspected in only one case. Two ill culture-positive nurses were identified on the job but no asymptomatic carriers were found among ward personnel. We conclude that influenza B cases were present among hospitalized patients in the absence of recognizable clusters of disease and that patients with community-acquired illness as well as nursing personnel may have introduced influenza into the hospital. Influenza B may be difficult to diagnose clinically in hospitalized patients, but viral throat cultures performed in all suspected cases should identify many infected patients.

Acyclovir therapy of varicella-zoster virus infections in immunocompromised patients

In a randomized, placebo-controlled, double-blind trial of intravenous acyclovir in the treatment of varicella zoster virus (VZV) infections, 8 of 20 immunocompromised children with varicella received acyclovir (500 mg/m2/dose three times daily for 7 days). There was no significant difference in skin healing between the acyclovir and placebo groups although there was a significant reduction in the incidence of development of pulmonary involvement during acyclovir treatment. Nineteen out of 34 patients received vidarabine (10 mg/kg/day for 5 days). Vidarabine significantly shortened the duration of new vesicle formation. Both drugs significantly reduced the incidence of visceral varicella, the most serious complication of VZV infection. An open trial also concluded that early treatment of varicella in these patients is essential. Of the 94 patients with zoster infection, 52 received acyclovir (500 mg/m2/dose infused over one hour three times daily for 7 days). Acyclovir recipients healed more rapidly, had fewer days of pain and shorter duration of viral shedding compared with placebo patients. The most important finding was that acyclovir significantly protected against progression of zoster as defined by development or progression of cutaneous dissemination and development of visceral zoster. Vidarabine seemed to be equally effective in this respect. The likelihood of cutaneous dissemination is related to the nature of the underlying condition. The in vitro sensitivity of VZV isolates from patients with second episode VZV infection during the trial did not change appreciably which suggests that VZV does not become resistant to acyclovir during therapy.

Acyclovir in shingles

Acyclovir given intravenously in either low dose (5 mg/kg every 8 h) or high dose (500 mg/m2 every 8 h) significantly reduced pain and accelerated skin healing in acute herpes zoster occurring in otherwise healthy adults. The higher dose also significantly reduced the duration of viral shedding. No significant effect on post-herpetic neuralgia could be demonstrated, although the higher dose showed a promising trend. No adverse effects were associated with the lower dose, but acyclovir at 500 mg/m2 resulted in nausea, vomiting and transiently elevated serum creatinine in a substantial number of patients.

Acyclovir halts progression of herpes zoster in immunocompromised patients

We conducted a placebo-controlled, double-blind study of acyclovir therapy for acute herpes zoster in immunocompromised patients. Of the 94 patients enrolled in the study, 52 had localized skin lesions at entry, and 42 had disseminated cutaneous zoster. A one-week course of intravenous acyclovir (1500 mg per square meter of body-surface area per day) halted progression of zoster in both groups, as determined by development or progression of cutaneous dissemination, development of visceral zoster, or proportion of cases deemed treatment failures. Significantly fewer patients treated with acyclovir within the first three days after the onset of exanthem had complications of zoster, as compared with patients treated with placebo (P = 0.02 by Fisher's exact test), but acyclovir also stopped progression of zoster in patients treated after three days of rash (P = 0.05 by Fisher's exact test). Acyclovir recipients with disseminated cutaneous zoster had a significantly accelerated rate of clearance of virus from vesicles, as compared with placebo recipients (P = 0.05 by the Breslow test).

Acyclovir therapy for acute herpes zoster

31 adults took part in a randomised, placebo-controlled, double-blind trial of intravenous acyclovir therapy (500 mg/m2 intravenously 3 times daily for 5 days) for acute herpes zoster. Acyclovir reduced pain, decreased erythema, prevented the formation of new lesions, and healed skin faster than did placebo. The duration of viral shedding was also significantly shorter in acyclovir recipients (2 days versus 5 days). However, 6(35%) of 17 acyclovir recipients had recurrence of pain after the drug was discontinued, and acyclovir did not appear to affect post-herpetic neuralgia. Acyclovir therapy was associated with a transient rise in serum creatinine levels, and may have been related to nausea and vomiting. Intravenous acyclovir was effective therapy for acute herpes zoster but the ideal treatment regimen might be a lower daily dose given for a longer period.

Survival of influenza viruses on environmental surfaces

To investigate the transmission of influenza viruses via hands and environmental surfaces, the survival of laboratory-grown influenza A and influenza B viruses on various surfaces was studied. Both influenza A and B viruses survived for 24-48 hr on hard, nonporous surfaces such as stainless steel and plastic but survived for less than 8-12 hr on cloth, paper, and tissues. Measurable quantities of influenza A virus were transferred from stainless steel surfaces to hands for 24 hr and from tissues to hands for up to 15 min. Virus survived on hands for up to 5 min after transfer from the environmental surfaces. These observations suggest that the transmission of virus from donors who are shedding large amounts could occur for 2-8 hr via stainless steel surfaces and for a few minutes via paper tissues. Thus, under conditions of heavy environmental contamination, the transmission of influenza virus via fomites may be possible.

Environmental influences on semen output

Semen output characteristics of 7,858 ejaculates of 57 commercial Holstein sires in artificial insemination were analyzed to estimate effects of environment over 3-yr. Large differences existed between bulls, first and second ejaculates, and intervals between collections for all measures of semen output. Effects of age of bulls were greatest for sperm concentration per milliliter and total sperm output, peaking at 4 yr of age. Original semen volume was influenced less by age. December was the best month for total sperm production even though June and July were the months for most volume of seminal fluid production. Total sperm output was highest on Fridays and lowest on Wednesdays. Effects of temperature and humidity and changes in temperature and humidity on semen output were small and inconsistent. These results do not support the assumption that semen output could be increased in controlled environment conditions.