The isolation of herpes simplex virus from rabbit corneas during latency

Herpes simplex virus type 1 (HSV-1) latency, as operationally defined, is a state in which cell-free infectious virus cannot be demonstrated in tissue at the time of sacrifice, but infectious virus can be isolated from the same tissue after prolonged cultivation. Latent HSV has been routinely detected in sensory ganglia of the infected dermatome. We have isolated HSV-1 (RE) from the corneas of 11% of infected rabbits which harbored virus in a latent state in trigeminal ganglia. HSV-1 (RE) was isolated from 10 of 88 cultures of corneal cells established following collagenase digestion of individual corneas taken from asymptomatic animals 118 days after infection. Virus was recovered only after prolonged primary culture and in some cases serial passage of corneal cells (range 5 to 26 days to initial cytopathic effect, n = 10). Virus was isolated from 68 of 68 trigeminal ganglia from the same rabbits by cocultivation of ganglion pieces with Vero cells (range 9 to 20 days to initial cytopathic effect, n = 68) while no cell-free virus was isolated from ganglia at the time of sacrifice. Virus isolation from corneas during the latent period occurred in a manner independent of prior antiviral or antiviral plus immunosuppressive therapy. Clinical evaluation of the corneas throughout the course of acute disease, stromal disease, and at the time of sacrifice provided no evidence that could be used to predict which corneas would yield virus. These data suggest that HSV-1 can remain in a nonreplicative state characteristic of latency in cells of rabbit corneas for long periods after infection and therapy of herpetic eye disease.

Synergistic antiherpes virus activity of acyclovir and interferon in human corneal stromal cells

Synergistic anti-herpes simplex virus type 1 (HSV-1) activity between acyclovir (ACV) and recombinant human interferon alpha A2 (IFN) was detected in cell cultures derived from human corneas. This activity was demonstrated when cells were infected at high multipicities of infection (5 pfu/cell) in both cytopathic effect reduction and yield reduction assays as well as in plaque reduction assays at low multiplicities. The synergistic effects occurred over a 30-fold range of concentrations of IFN (6-200 IU/ml) and ACV (0.15-5 microM) at various ratios of the drugs. The augmentation of antiviral activity was greatest when cells were treated with IFN prior to infection and ACV following infection. The addition of IFN after infection, with simultaneous ACV treatment, also resulted in enhanced anti-HSV-1 activity. The combination of IFN with ACV did not increase the cytotoxicity of ACV. The synergistic antiviral activity in corneal cells may account for the previously reported enhanced efficacy of combined treatment with IFNs and nucleoside analogs for therapy of herpetic keratitis.

Pointing

The roles of vision and proprioception in the task of pointing at a distant object were investigated. When guided solely by proprioception, subjects pointed from the shoulder through the finger to the object, down the long axis of the arm. When vision was present, it dominated proprioception and subjects pointed with the fingertip close to a sight line from the eyes to the object.

Proprioception in the neck

Proprioception in the neck was investigated in normal human subjects. Three experiments studied rotation of the head about a vertical axis on the body. Accuracy of pointing, thresholds for detection of passive movement, and control of fine movement were tested. Comparison of the accuracy of pointing at the big toe with the nose and with the arm, showed a smaller scatter of angular misalignments when pointing with the arm. However, the arm pointed systematically off target. Pointing at the target toe by turning the head was not significantly more accurate than aligning the nose and toe by turning the chair and body with the head fixed. The highest threshold found for the detection of the direction of passive movement of the head relative to the body was 1.4 degrees angular displacement. Thresholds were highest at the slowest angular velocity and dropped as angular velocity increased. When the head was turned on the body thresholds were lower than when the body was turned and the head held still. Control of fine angular movements of the head and of the distal phalanx of the right thumb were compared by measuring subjects' accuracy in guiding a cursor through a path on a computer screen by turning the head or moving the thumb. The thumb was found to be better controlled than the head.

Inhibition of the differentiation of 3T3-L1 cells by interferon-beta and difluoromethyl ornithine

Both mouse interferon-beta (MuIFN-beta) and the inhibitor of ornithine decarboxylase (ODC), alpha-difluoromethyl ornithine (DFMO), inhibited the differentiation of mouse 3T3-L1 fibroblasts into adipocytes in a dose-dependent manner. DFMO and MuIFN-beta added together to cultures that were induced to differentiate produced an additive anti-differentiation effect. In contrast to this additive cellular effect, DFMO reduced the antiviral activity of MuIFN-beta in both undifferentiated and differentiated cells; DFMO alone had no detectable effect on replication of encephalomyocarditis virus. Putrescine, the product of ornithine decarboxylation, when added to 3T3-L1 cultures (i) enhanced differentiation, (ii) reversed completely the inhibition of differentiation by DFMO, but (iii) had little effect on the anti-differentiation effect of MuIFN-beta. Polyamine content changed four-fold or less in cultures treated with 0.5 mM DFMO and less than two-fold in cultures treated with 100 IU/ml MuIFN-beta for seven days. Thus, it appears not only that MuIFN-beta and DFMO inhibit differentiation of 3T3-L1 cells by different mechanisms but also that the antiviral action of IFN does not involve the regulation of polyamine metabolism by ornithine decarboxylase.

Antiviral and antidifferentiative activities of interferon beta and gamma in relation to their induction of double-stranded RNA-dependent protein kinase activity in 3T3-L1 cells

Mouse interferons beta (IFN-beta) and gamma (IFN-gamma) inhibit the differentiation of 3T3-L1 fibroblasts into adipocytes when added to cultures at the time of induction of differentiation. Differentiation, as measured by incorporation of radiolabeled leucine into lipids, was inhibited 50% by approximately 1-3 units/ml of either IFN-beta or IFN-gamma, with maximum inhibition of differentiation achieved with 100 units/ml of either IFN. The magnitude of antiviral activity induced by IFN-beta and IFN-gamma was similar in differentiated and undifferentiated 3T3-L1 cells, although the slopes of the dose-response curves were different; IFN-gamma induced an antiviral state with greater efficiency than IFN-beta in differentiated and undifferentiated 3T3-L1 cells. By contrast, IFN-beta induced the double-stranded RNA-dependent P1 protein kinase more efficiently than did IFN-gamma in both differentiated and undifferentiated cells. However, IFN-beta and IFN-gamma both induced greater phosphorylation of protein P1 in cell-free extracts prepared from differentiated adipocytes than in extracts from undifferentiated fibroblasts. Cultures treated with either beta or gamma IFN throughout 8 days of differentiation continued to produce double-stranded RNA-dependent protein kinase in a manner dependent on IFN dose. These results suggest that the antiviral and antidifferentiative activities of IFN-beta and IFN-gamma in 3T3-L1 cells involve different molecular mechanisms.

Inhibition of the differentiation of 3T3-L1 cells by interferon-beta and difluoromethyl ornithine

Both mouse interferon-beta (MuIFN-beta) and the inhibitor of ornithine decarboxylase (ODC), alpha-difluoromethyl ornithine (DFMO), inhibited the differentiation of mouse 3T3-L1 fibroblasts into adipocytes in a dose-dependent manner. DFMO and MuIFN-beta added together to cultures that were induced to differentiate produced an additive anti-differentiation effect. In contrast to this additive cellular effect, DFMO reduced the antiviral activity of MuIFN-beta in both undifferentiated and differentiated cells; DFMO alone had no detectable effect on replication of encephalomyocarditis virus. Putrescine, the product of ornithine decarboxylation, when added to 3T3-L1 cultures (i) enhanced differentiation, (ii) reversed completely the inhibition of differentiation by DFMO, but (iii) had little effect on the antidifferentiation effect of MuIFN-beta. Polyamine content changed four-fold or less in cultures treated with 0.5 mM DFMO and less than two-fold in cultures treated with 100 IU/ml MuIFN-beta for seven days. Thus, it appears not only that MuIFN-beta and DFMO inhibit differentiation of 3T3-L1 cells by different mechanisms but also that the antiviral action of IFN does not involve the regulation of polyamine metabolism by ornithine decarboxylase.

A comparison of assessment techniques measuring the effects of methylphenidate, secobarbital, diazepam and diphenhydramine in abstinent alcoholics

In two studies, we studied the comparative sensitivity of different subjective and objective measures to methylphenidate (10 and 20 mg) and secobarbital (100 mg) versus placebo, and diphenhydramine (50 mg) and diazepam (10 and 20 mg) versus placebo in abstinent alcoholics. Subjective measures used were the Visual Analog Mood Scale and the Profile of Mood States. Objective measures were the Stroop and two microcomputer-controlled tasks developed in our lab - a dual pursuit tracking/reaction time task (P-Trak) and a reaction time task with regular and irregular preparatory intervals (PI) of varying length (Reactest). In addition, several baseline measures (Eysenck Personality Inventory, Spielberger State-Trait Anxiety Inventory and NIMH Mood Scale Elderly) were evaluated for their correlation to drug response. All three central nervous system depressants impaired performance on Reactest at the longer PIs and showed a main effect with irregular PIs, but only the 20-mg dose of diazepam impaired reaction time at the shortest PI and showed a main effect with regular PIs. On P-Trak, secobarbital and diazepam 20 mg impaired both tracking and reaction time, while methylphenidate 20 mg improved only the reaction time component. Only diazepam 20 mg affected mood. No effects were noted on the Stroop. The implications of these findings are discussed. Both P-Trak and Reactest with long PIs were more sensitive than VAMS, POMS or Stroop to drug effects. As lower doses of central nervous system depressants impaired reaction time only with longer PIs and showed a main effect only with irregular PIs, cognitive effects of these drugs may be missed if only subjective or short, regular PI tasks are examined.(ABSTRACT TRUNCATED AT 250 WORDS)

Cortical blindness after left internal mammary artery to left anterior descending coronary artery graft angiography

We describe a case of transient cortical blindness following internal mammary artery to left anterior descending coronary artery graft angiography. This dramatic, infrequent, and self-limiting complication so far has not been described in the cardiovascular literature. In the present era of internal mammary artery use for the left coronary artery grafting, the angiographer should be familiar with the diagnosis, prevention, and management of complications previously seen mostly during the posterior cerebral circulation angiography.

Splenic conservation and the management of splenic artery aneurysm

We report two patients with splenic artery aneurysm diagnosed by CT, treated by proximal and distal ligation of the splenic artery and followed for two years by CT to assess splenic size and pitted erythrocyte counting to assess function. Literature review shows that excision of the aneurysm and splenectomy is usual but with growing regard for conservation of splenic tissue we suggest that proximal and distal ligation of the artery is a preferable alternative as shown by splenic function tests in these patients.

Herpetic keratitis in experimental vitamin A deficiency

Herpes simplex virus type I (KOS) was instilled onto the eyes of rabbits with experimentally induced xerophthalmia (vitamin A deficient) and control animals fed a vitamin A supplemented diet. The severity of the herpes virus-induced corneal disease, assessed by biomicroscopic examination and by counting the number of corneal lesions as well as by determining the virus titers, was significantly less in vitamin A deficient animals than in controls. Infection of the corneas of the vitamin A deficient rabbits with herpes simplex virus did not precipitate keratomalacia. The few lesions present on the corneas of the vitamin A deficient animals were in the corneal periphery, which was less keratinized than the central cornea. Electron microscopy suggested that virus was capable of replicating in the basal and wing cells in the peripheral corneal lesions in the vitamin A deficient animals. These studies indicate that vitamin A deficiency alone may not predispose the host to more severe ocular herpesvirus infections.

The antiherpesvirus activity and cytotoxicity of sangivamycin

Sangivamycin, 4-amino-5-carboxamido-7-(beta-D-ribofuranosyl)-pyrrolo[2,3-d]-pyrimidine is a structural analog of adenosine belonging to a group of nucleosides classified as pyrrolopyrimidines. Sangivamycin, an adenosine deaminase resistant analog, was found to inhibit the replication of three strains of herpes simplex virus type 1 (HSV-1) by 50% (ED50) at a concentration approximately equal to the concentration which inhibits cell growth by 50% (LD50). Both Vero cells and rabbit corneal stromal cells in exponential growth were about 10-fold more sensitive to the drug than quiescent cells. The selectivity indices of sangivamycin indicated that the drug was not a highly selective antiviral agent and, therefore, would offer no advantage over drugs currently available for the treatment of herpetic keratitis.

Adenosine deaminase in herpes simplex virus induced corneal stromal disease

The development of herpes simplex virus (HSV)-induced disciform stromal disease produced by the intrastromal injection of the RE strain of HSV-1 is characterized by concurrent increases in adenosine deaminase (ADA) activity and corneal thickness. ADA activity increased from 8.6 units/cornea in normal corneas to about 14.1 units and 31.1 units in mock-infected controls and HSV-infected corneas respectively by 15 days postinjection. The molecular weight species of ADA in the corneas of HSV-infected rabbits appeared altered relative to that present in corneas which were not infected. A single topical dose with as low as 0.1% 2'-deoxycoformycin (dCF), an ADA inhibitor possessing immunosuppressive activity, was capable of totally inhibiting the corneal ADA activity. Titration of the free dCF in the cornea following a single topical dose of 0.25% dCF indicated that enough dCF remained in the cornea 24 hrs after instillation to totally inhibit all corneal ADA plus 66 units of additional enzyme. These data suggest that ADA may be a suitable target for immunosuppressive therapy during HSV-induced disciform stromal disease.

Interferon production in inbred mice during herpetic eye disease

Low levels (less than 5 units/eye) of interferon (IFN) were detected in the eyes of BALB/c and C57BL/6 mice one to five days after instillation of 10(7) pfu/eye of herpes simplex virus type 1 (HSV) onto scarified corneas. This dose of virus produced herpetic keratitis characterized by dendritic epithelial lesions one day post infection in both strains of mice. The disease progressed to severe necrotizing stromal keratitis in the eyes of all BALB/c mice, but only three of 10 eyes of C57BL/6 mice by 21 days after infection. Footpad immunization 30 days prior to ocular infection protected both strains from stromal disease, but did not enhance IFN production in the eye. At lower inoculating doses of virus (less than or equal to 10(5) pfu/eye), C57BL/6 mice showed greater resistance to stromal disease and produced less virus over a shorter period of time than BALB/c mice. No IFN was detected at any time after infection with doses of virus less than 10(7) pfu/eye, nor was IFN detected in plasma of any infected mice. The failure to detect high levels of IFN in homogenates of eyes did not reflect an inability of ocular tissues to produce IFN since IFN-beta was detected as early as two hours after topical treatment with the potent IFN inducer, carboxymethylacridanone (CMA). The two mouse strains produced similar levels of IFN in the eye in response to CMA. These data indicated that the relative resistance of mice to HSV eye infection was not related to the rapid local production of IFN, nor was resistance related to systemic IFN production in plasma or spleen.

Seasonal changes in the biochemical indices of vitamin D deficiency in the elderly: a comparison of people in residential homes, long-stay wards and attending a day hospital

The seasonal changes in the biochemical indices of vitamin D nutrition have been measured in elderly people with differing requirements for institutionalized care. Residents of local authority homes (LAH) showed an increase in serum 25-hydroxyvitamin D3 [25(OH)D3] between spring and autumn (means 14-17 nmol/l, P less than 0.002). No significant seasonal changes were seen in patients on long-stay wards [(GW) serum 25(OH)D3 9.5 and 9.5 nmol/l] and in day-hospital attenders [(GDH) 25 and 26.8 nmol/l]. Significant differences (P less than 0.02 to P less than 0.0001) were found between the mean serum 25(OH)D3 amongst the three groups. A significant linear relationship (r = 0.84, P = 0.036) was found between mean serum 25-hydroxyvitamin D2[25(OH)D2] and dietary vitamin D2. The intake of vitamin D was suboptimal in all groups. The incidence of 25-hydroxyvitamin D deficiency [25(OH)D less than 12.5 nmol/l] varied from 11.7% of residents in LAH in autumn to 47% of GW patients in spring; but hypocalcaemia occurred less often (LAH 1.3% in autumn, GW 4.7% in spring). The diet assumes a greater role in protecting against vitamin D deficiency when the total 25(OH)D is low. Because most diets contain insufficient amounts of vitamin D, elderly institutionalized people will remain at high risk of developing vitamin D deficiency unless specific preventative measures are adopted.

Annual cycles of plasma and testicular androgens in the lizard Tiliqua (Trachydosaurus) rugosa

Androgen production during the annual reproductive cycle was investigated in the male scincid lizard Tiliqua (Trachydosaurus) rugosa. Concentrations of testosterone and epitestosterone were measured in plasma and testis (incubated and nonincubated) using radioimmunoassay. Morphological and histological techniques were used to determine the anatomical changes in the testis. Mating behavior was observed during spring, and sperm were most numerous in the testis at this time. Histological evidence and changes in testicular weight indicated that spermatogenesis begins in autumn and culminates in spring. Testicular regression occurred soon after mating. Plasma concentrations of both androgens were maximal during spring and minimal during summer. The maximal concentrations were approximately 500 and 150 nmol/liter (epitestosterone and testosterone, respectively). The minimal plasma concentrations were 250 and 15 nmol/liter, respectively. Plasma and testicular androgen cycles followed a pattern similar to that of the spermatogenetic cycle, suggesting the possible involvement of one or both of these androgens in the control of spermatogenesis and mating behavior in these lizards.

Effect of temperature on the seasonal production of testicular androgens, in vitro, by the lizard Tiliqua rugosa

The effect of temperature on the seasonal production of testicular androgens, in vitro, was examined in the scincid lizard Tiliqua (Trachydosaurus) rugosa. Testicular tissue was incubated, in vitro, at various temperatures (18, 25, 32 and 37 degrees C). Endogenous androgens, testosterone and epitestosterone, were measured by radioimmunoassay. Epitestosterone production was maximal at 37 degrees C and minimal at 18 degrees C. There was no consistent effect of incubation temperature on testosterone production. Incubation temperature had no effect on the seasonal pattern of androgen production. The results suggest that temperature may play a part in the regulation of androgen biosynthesis in T. rugosa.

Interferon production and sensitivity of rabbit corneal epithelial and stromal cells

The induction of interferon and the ability of interferon to induce the antiviral state were studied using rabbit corneal epithelial and stromal cells which were cultured for fewer than five passages. Interferon titers in the range of 7000 units/ml were induced in epithelial cell cultures and 76,000 units/ml in stromal cell cultures treated with UV-inactivated bluetongue virus. The interferon induced was stable to pH 2.0 treatment and heating to 56 degrees C for 16 hr. Infection of epithelial and stromal cell cultures with various strains of herpes simplex virus type 1 showed that all strains tested replicated to equivalent titers in the respective cell types, and that no detectable interferon was induced in stromal cells and only trace amounts in epithelial cells. Exogenously supplied rabbit interferon induced the antiviral state in cultures of both cell types restricting the replication of not only encephalomyocarditis virus but also herpes simplex virus. Sixty to ninety units of rabbit interferon reduced HSV-1 virus replication by 50%. Human interferons had less than 27% of the antiviral activity in rabbit cells than they had in a human cell line. The data indicate that exogenously supplied interferon may act to reduce the severity of herpetic keratitis by directly inducing the antiviral state in corneal epithelial and stromal cells. However, interferon endogenously produced by rabbit corneal cells in response to HSV-1 infection probably plays a minor role in the pathogenesis of ocular HSV-1 infections.

Vitamin D prophylaxis in the elderly: a simple effective method suitable for large populations

A comparison of two regimens of vitamin D prophylaxis in elderly institutionalized subjects has been made. Sixty-six subjects received 2.5mg vitamin D2 by mouth in December 1982; a further group of 62 received the same dose in December 1982 and again in June 1983. Blood samples have been analysed for 25-hydroxyvitamin D2 [25(OH)D2] in 10 subjects from each group over a 12-month period. The serum 25(OH)D2 was maintained at normal concentrations for most of the year in the once-a-year dosage group but at the end of 12 months only 60% were fully protected. The twice-per-year regimen offered complete protection maintaining the serum 25(OH)D2 above the threshold associated with osteomalacia. It is concluded that a twice-yearly regimen of vitamin D supplementation is a practical method for prophylaxis in institutionalized elderly people.

Identification of epitestosterone in the plasma and testis of the lizard Tiliqua (Trachydosaurus) rugosa

Blood and testicular extracts of the scincid lizard Tiliqua (Trachydosaurus) rugosa were analyzed using thin-layer, column, and high-performance liquid chromatography. The major androgens isolated were epitestosterone, testosterone, and androstenedione. Epitestosterone was characterized by chromatography in several systems, and by derivative formation. Epitestosterone was further identified in testicular extracts by gas chromatographymass spectrometry. Immunoreactive material was detected in tissue extracts using an antiserum specific to epitestosterone. The maximum concentration of epitestosterone in blood, measured by radioimmunoassay, was four times that of testosterone (approximately 900 and 200 nmol/l, respectively). Epitestosterone could not be detected in the blood of intact females and the concentration of this steroid was low in castrate males. The maximum testicular concentrations (pmol/testis) were 390 (nonincubated) and 2050 (incubated) for epitestosterone, and 2025 (nonincubated) and 1040 (incubated) for testosterone. Both plasma and testicular concentrations showed considerable seasonal variation. The identification of endogenous epitestosterone confirms the results of earlier investigations using radioactive substrates. The occurrence of this steroid as a major product of the testis in T. rugosa is discussed in relation to androgens in reptiles and other vertebrates.

Neuropharmacologic and neuropathologic effect of fenvalerate in mice and rats

B6C3F1 mice and Sprague-Dawley rats displayed the characteristic signs of pyrethroid intoxication following single oral doses ranging from 56 to 320 and 133 to 1000 mg/kg fenvalerate, respectively. The LD50s for mice and rats were 180 and 776 mg/kg, respectively, with corn oil as the vehicle. Signs of neurologic deficit such as splayed gait, tremors, ataxia, and hind limb incoordination were observed at doses of greater than or equal to 100 mg/kg (mice) and greater than or equal to 133 mg/kg (rats) within 1-8 hr after dosing. These signs had disappeared in most animals within 72 hr. Slight peripheral nerve fiber damage was detected in surviving mice and rats sacrificed 10 days after dosing. The incidence and severity were dose related at doses greater than or equal to 56 and greater than or equal to 180 mg/kg; however, even at lethal doses, evidence was lacking for the presence of nerve lesions in several animals. Thus two distinct neurologic effects were observed: a reversible ataxia/incoordination and a neuropathologic effect manifested as sparse axonal damage in peripheral nerve.

The determination of effective antiviral doses using a computer program for sigmoid dose-response curves

A computer program was designed to construct best fit sigmoid dose-response curves for determination of the dose required to reduce the yield of virus by 50%, effective antiviral dose (ED50). A single antiviral agent, 9-beta-D-arabinofuranosyladenine, was examined for effectiveness against four strains of herpes simplex virus type 1. The resulting ED50 values were compared with those obtained by probit analysis. The statistical parameters obtained from sigmoid curve fit program were utilized to evaluate statistical differences between ED50 values for resistant and sensitive virus strains and to evaluate the goodness-of-fit of the regression line to the data. In addition, using this analytical method, it was shown that a change in one experimental variable, i.e., multiplicity of infection, in the yield reduction assay significantly affected the apparent ED50 value. The computer program was easily utilized for analysis of data obtained from both plaque reduction and yield reduction assays and generated the parameters necessary for statistical comparison of relative antiviral activity of any antiviral agent.

The effects of retinoids on the replication of herpes simplex virus type 1

Topical treatment of primary herpetic keratitis with 0.25% retinoic acid was effective in significantly diminishing the severity of epithelial lesions in rabbits. Antiviral activity against herpes simplex virus type 1 was also demonstrated in cell culture. Retinoic acid treatment of virus particles for 24 hours had no effect on the infectivity of the virus. At effective antiviral concentrations in cell culture, retinoic acid had toxic action on two different cell lines as detected by an increase in cellular generation time or inhibition of DNA synthesis. Topical instillation of retinoic acid into the eyes of rabbits at the effective antiviral dose (0.25%) had no inhibitory effect on corneal wound closure but did reduce the rate of incorporation of thymidine into DNA by 27%. These studies suggest that although retinoic acid may inhibit the replication of herpes simplex virus type 1, it is difficult to distinguish antiviral effects from anticellular effects.

Markedly enhanced production of gamma interferon in murine T lymphocytes treated with lentil lectin and the diterpene ester, mezerein

Gamma interferon (IFN-gamma) was induced in murine splenocytes first stimulated to grow by concanavalin A (Con A) and subsequently treated for 3 h with the diterpene ester, mezerein (MZN) and then with lectin from Lens culinaris for 24 h. Yields as high as 60,000 u/ml were obtained in cells from either male or female, random-bred, white Swiss mice or inbred C67B1/6 mice. Antibody to Thy 1.2 surface antigen completely obliterated the mouse gamma interferon (MuIFN-gamma) response, whereas anti-Lyt 1.2 and anti-Lyt 2.2 each destroyed a portion of the lymphocyte population responsible for MuIFN-gamma production. Kinetic analysis of production and release showed that IFN was detectable in culture fluids within 4 h after treatment with very little IFN remaining cell-associated (less than 10%). A simple, rapid, and economical two-step purification procedure involving ammonium sulfate fractionation and yeast RNA affinity chromatography resulted in as much as 770-fold purification to achieve specific activities greater than 10(7) u/mg protein. The purified MuIFN-gamma was shown to be predominantly acid-labile, inactivated by sodium dodecyl sulfate (SDS), and neutralized by antiserum to MuIFN-gamma. Approximately 10% of the MuIFN-gamma was acid-stable and SDS-resistant, but was still neutralized by anti-MuIFN-gamma serum. Two molecular weight peaks of about 40 and 20 kD were demonstrated by SDS-polyacrylamide gel electrophoresis. Isoelectric focusing in polyacrylamide slab gels gave a relatively heterogeneous band of activity between pH 5.5 and 6.5. The mechanism by which the combination treatment described enhances MuIFN-gamma production so markedly remains unknown, but the degree of enhancement is greater than additive.

Antibiotics, sore throats and acute nephritis

A study was carried out of 274 children in Scotland aged 0 to 13 years recorded as having had acute nephritis over a four-year period (1976-79). The medical records for 223 of the patients were examined and 79 cases of poststreptococcal nephritis were identified, giving an estimated incidence of 2.1 episodes per 100,000 children per year. Using a number of assumptions, the authors sought the answers to two important questions: What is the risk that glomerulonephritis will develop after sore throat/inflamed throat illness? Is this risk influenced by the prescribing of an antibiotic for the original illness?The risks of developing nephritis after an antibiotic-treated sore throat and after a non-antibiotic treated sore throat were assessed as being equivalent (1:13,000 and 1:17,000 respectively). Furthermore, it appears that, during his lifetime, a general practitioner has a chance of only one in six of seeing a child with post-streptococcal nephritis after a sore throat.

Listeria monocytogenes prosthetic valve endocarditis

Listeria monocytogenes is a rare cause of prosthetic valve endocarditis and in all of the four reported cases has occurred as a late complication. Bacteriologic cure of the infection has been obtained in all reported patients, using a standard regimen of either penicillin or penicillin and an aminoglycoside. The two deaths were associated with Starr-Edwards prostheses in the aortic position and have been attributed to embolic phenomena occurring after bacteriologic sterilization of the infected valve.

Leucine catabolism during the differentiation of 3T3-L1 cells. Expression of a mitochondrial enzyme system

Leucine can be utilized efficiently as a precursor for lipid biosynthesis by adipose tissue, especially in the presence of glucose or glucose and insulin. During the differentiation of 3T3-L1 fibroblasts to adipocytes, the rate of lipid biosynthesis from L-[U-14C]leucine increases at least 30-fold and lipogenesis, with [U-14C] acetate as the precursor, increases by 10- to 15-fold. The specific activities of two mitochondrial dehydrogenases in the leucine oxidative pathway, the branched chain alpha-ketoacid dehydrogenase and isovaleryl-CoA dehydrogenase, as well as of leucine:alpha-ketoglutarate transaminase, increase at least 20-fold during the adipose conversion. Isovaleryl-CoA dehydrogenase was assayed in crude extracts using a specific fluorimetric method employing electron transfer flavoprotein as the electron acceptor for the flavoprotein dehydrogenase. The specific activity of 3-hydroxy-3-methylglutaryl-CoA lyase, the mitochondrial enzyme catalyzing the terminal reaction in the leucine degradation pathway, increases 4-fold during differentiation. The increases in the specific activities of the mitochondrial enzymes occur without a change in the specific activity of cytochrome oxidase, indicating that the increases do not simply reflect proliferation of mitochondria. The biosynthesis of at least 20 soluble mitochondrial polypeptides is enhanced during the adipose conversion of the fibroblasts as determined by polyacrylamide gel electrophoresis following incubation of the cells with [35S] methionine. The results provide a conservative estimate of the extent of changes in mitochondrial soluble proteins during the adipose conversion. They also establish that differentiated 3T3-L1 adipocytes metabolize leucine like mature adipose tissue and illustrate the roles of the branched chain alpha-ketoacid dehydrogenase and isovaleryl-CoA dehydrogenase in lipogenesis.

Affinity chromatography of acetylcholinesterase from Electrophorus electricus electroplax. Investigations on 9-aminoalkylacridine affinity ligands

The neural enzyme 11-S acetylcholinesterase (E.C. 3.1.1.7) was purified by affinity chromatography from a trypsin digest of Electrophorus electricus electric organ. Unquaternized affinity ligands were reported which were comparable in efficacy to the routinely employed "quaternized acridine MAC ligand". A study was made of the quaternization reactions of various 9-aminoalkylacridines and 9-aminoacridine along with their relative binding affinities to acetylcholinesterase. Ease of synthesis in conjunction with the column performance of these unquaternized 9-aminoalkylacridine compounds made them the preferred affinity ligand in acetylcholinesterase chromatography. A new carbodiimide synthetic route for these unquaternized ligands was described.

Induction in rainbow trout of an acute phase (C-reactive) protein by chemicals of environmental concern

1. Rainbow trout, Salmo gairdneri, produce elevated amounts of a serum acute phase (C-reactive) protein (CRP) when administered a variety of chemicals of environmental importance. 2. Compounds administered in doses which induce the cytochrome(s) P450 catalytic enzymes in trout hepatic microsomes also induce serum CRP. 3. However, an interferon-inducing virus does not induce CRP. Interferon induction by the virus is not significantly inhibited by chemicals which induce trout cytochrome(s) P450. 4. Simultaneous administration of chemicals and virus or virus alone results in depression of P450 protein production and only minor induction of CRP. 5. Thus, as with mammals, a reciprocating relationship appears to exist between the hemeprotein monooxygenase and immune systems of this freshwater teleost, and C-reactive protein appears to fit the reciprocating scheme closer to the cytochromes P450 response.

Reconstitution of plant nitrate reductase by Escherichia coli extracts and the molecular cloning of the chlA gene of Escherichia coli K12

Extracts from Escherichia coli, wild type and chlB, chlC, chlD, chlE, and chlG, but not chlA mutants, were able to reconstitute the nitrate reductase activity in Nicotiana tabacum cnx68 and Hyoscyamus muticus MA-2 mutant extracts. Because cnx68 and MA-2 lack the molybdenum cofactor required for nitrate reductase activity, these results indicate that the functional chlA gene is essential to produce the molybdenum cofactor in E. coli. A clone containing a gene capable of complementing the chlA mutation SA493 was obtained on a large cosmid pJT1. A 1.9 kb BclI fragment subcloned from pJT1 in the vector plasmid pBR322 was shown to complement the chlA SA493 mutant when inserted in either of the two possible orientations. This suggested that the chlA gene was contained intact, including its own promoter, on the 1.9 kb BclI fragment.

Observations on the dietary practices of Asians in the United Kingdom

The efficacy of a health education campaign to improve the vitamin D status of Asians has been assessed. The average daily consumption of vitamin D has not changed significantly over a 10-yr period, although the use of margarine has increased. No consistent relationship could be demonstrated between the dietary consumption of vitamin D, phytate, chuppatty flour, fibre, oxalate or meat and the serum 25 hydroxyvitamin D concentration. This supports the view that dietary factors play only a minor role in the aetiology of vitamin D deficiency among Asian immigrants.

Seasonal changes in serum 25-hydroxyvitamin D concentrations among Asian immigrants

1. The exposure of Asian immigrants to effective quantities of naturally occurring ultraviolet light was investigated by observing the increase in serum 25-hydroxyvitamin D concentrations during the summer months. 2. The seasonal increase in adult males was greater than in adult females. 3. There was a significant positive correlation between the seasonal increase and the prevailing 25-hydroxyvitamin D concentration, compatible with the view that the accumulation of inadequate stores of 25-hydroxyvitamin D during the summer results in the low serum concentrations seen in Asian immigrants.

Chemotherapy of herpetic keratitis induced by acyclovir-resistant strains of herpes simplex virus type 1

The severity of herpetic keratitis induced by 9-(2-hydroxyethoxymethyl) guanine-resistant strains of herpes simplex virus was significantly reduced by cotherapy with 9-beta-D-arabinofuranosyladenine (ara-A) and 2-deoxycoformycin. Therapy with 5-trifluoromethyl-2'-deoxyuridine (F3TdR) significantly reduced the severity of keratitis induced by an acyclovir-resistant strain with a defective DNA polymerase. Therapy with 3 percent acyclovir ointment slightly reduced the number of herpetic lesions produced by either deoxypyrimidine kinase or DNA polymerase defective viruses, despite these viruses being 100 to 1000 times more resistant to acyclovir than the wildtype strain. Therapy with 3 percent ara-A ointment alone significantly reduced the severity of lesions produced by the wildtype herpes strain. Therapy with ara-A alone did not reduce the severity of disease induced by any of the acyclovir-resistant mutants. The sensitivity of the wildtype and mutant viruses to nucleoside analogs was confirmed by yield-reduction assays conducted with Vero cells. These studies indicate that cotherapy with ara-A and an adenosine deaminase inhibitor was a reasonable alternative therapy for keratitis due to mutants resistant to therapy with nucleoside analogs which require the virus-specified deoxypyrimidine kinase or DNA polymerase, while ara-A alone was not an effective alternative.

Angiographic diagnosis of aorto-right atrial fistula from acute dissecting aneurysm of the ascending aorta

An uncommon complication of acute dissecting hematoma of the aorta is rupture into a right heart chamber. We report a case in which the dissection hematoma ruptured into the right atrium in addition to causing aortic valve incompetence. These features were diagnosed angiographically. Thereafter, successful surgical repair was performed.

Protection against Japanese encephalitis virus in mice and hamsters by treatment with carboxymethylacridanone, a potent interferon inducer

A low-molecular-weight chemical inducer of interferon, 10-carboxymethyl-9-acridanone (CMA), effectively prevented death caused by Japanese encephalitis virus (JEV) injected peripherally into weanling mice and baby hamsters. Marked reductions in mortality were seen in mice when a single dose of CMA was administered intraperitoneally, subcutaneously, or intramuscularly to animals challenged intraperitoneally with JEV. The degree of protection was dependent on dose and time of administration of CMA in relation to virus challenge: all hamsters given CMA on the same day as JEV survived, with lesser although still significant protection when CMA was given one or two days after JEV. Viremia, an important characteristic of the pathogenesis of natural JEV infection, was reduced nearly 10,000-fold in hamsters treated with CMA. Thus, in the experimental animal models developed for these studies, CMA provided marked therapeutic and prophylactic effect against JEV.

High-yield interferon induction by 10-carboxymethyl-9-acridanone in mice and hamsters

10-Carboxymethyl-9-acridanone (CMA) was shown to be a very potent interferon inducer in young and old Swiss albino as well as congenitally asplenic mice. This compound (molecular weight, 275) induced titers of interferon in plasma comparable to those obtained with the best viral inducers, attaining > 400,000 U/ml in mice in 2 to 3 h. CMA concentrations were highest in mouse plasma 1 h after intraperitoneal or oral delivery. Induction was dose dependent over a wide range. Intraperitoneal, subcutaneous, or intramuscular injections of CMA gave comparable ranges of interferon titers. Oral delivery by gavage gave lower titers (65,000 U/ml), but higher than those reported with other low-molecular-weight interferon inducers in mice. CMA injected into week-old hamsters (which usually produce iterferon poorly) induced levels of interferon as high as 6,400 U per ml of plasma in a dose-dependent fashion, but kinetics of interferon induction was less rapid than in mice. The mouse and hamster interferons induced by CMA had physical characteristics similar to those of virus-induced interferons of the homologous species. The unusually high yields of interferon obtainable with this chemical inducer suggest its use for further experimental antiviral or antitumor therapy.

Acridine araphanes: a new class of probe molecules for biological systems

The bis-acridine ring system forms the basis for new biophysical probes of novel stereochemistry. Spectral data indicate that certain alkylene bridged bis-9-aminoacridines have a parallel plane conformation of predictable interplane distance. The parallel plane conformation is independent of solvent and thus is different from nucleic acid systems. This stable conformation allows these compounds to be used as sensitive "rulers" for describing binding site geometry in cholinergic enzymes and in the delineation of the mechanism of allosteric control in acetylcholinesterase.

Yaba virus-specific DNA in the host cell nucleus

DNA-DNA hybridization studies show that Yaba virus-specific DNA is present in the host cell nucleus late in the infection cycle. The nuclear DNA appears to exist as a complete genome, not convalently linked to host cell DNA, as demonstrated by sedimentation analyses. The DNA apperas to be synthesized in the nucleus, since its level of incorporation of label is ten times the background incorporation detectable in the cytoplasm. Extraction of the nuclei by treatment with SDS and EDTA after precipitation with 1 M NaCl separates most of cellular DNA from the Yaba virus-specific DNA.

Inhibition of simian virus 40 DNA synthesis in Yaba virus-preinfected cells

The effect of Yaba virus preinfection on DNA synthesis in SV40-infected Jinet cells was studied. Time-course synthesis studies were conducted using the incorporation of labeled thymidine. Yaba virus preinfection resulted in the inhibition of SV40 DNA synthesis when the elapsed time between Yaba virus and SV40 infections was three days. This inhibition was demonstrated by hybridization studies and sedimentation analysis. In addition, the usual stimulation of cellular DNA synthesis induced by SV40 infection was inhibited. This inhibition occurred at a time in Yaba virus infection when no cytoplasmic Yaba virus-specific DNA synthesis occurred.

Phenytoin inhibition: failure to inhibit periosteal responses to lathyrogen

beta-Aminopropionitrile (BAPN) administered to rats has caused exostosis formation at sites of muscle attachment and also caused delay in the healing of soft tissue wounds and of bone fractures. Since phenytoin sodium has an opposite effect on wound healing, bone fractures, and the tensile strength of connective tissues, an experiment was performed to determine whether or not BAPN could produce periosteal exostoses in the presence of phenytoin. Rats that were given both BAPN and phenytoin produced similar exostoses as rats that were given BAPN alone. This indicates that phenytoin does not prevent inhibition of lysyl oxidase by BAPN, does not promote increased tensile strength of connective tissues in the presence of BAPN, and does not facilitate the detoxification of BAPN. Further, no evidence for an increased cellular response with phenytoin was observed. The mechanism by which phenytoin promotes wound healing is still unknown.