Assessment of Babesia spp. prevalence in various domestic animals across Southern Punjab, Pakistan

Parasitic diseases, notably babesiosis, exert a substantial impact on the global cattle industry, posing challenges to commerce, economies, and human health. This study, conducted in Southern Punjab, Pakistan, aimed to assess the prevalence of Babesia spp. across various livestock species using microscopic and PCR methods. A total of 180 blood samples (60 from each district) were systematically collected from apparently healthy animals, with 36 samples obtained from each domestic animal species, including camel, cattle, buffalo, goat, and sheep, noting that 12 samples were collected from each district for each animal species. Overall prevalence was determined to be 32.8% (59/180), with varying rates among species: 25.0% in cattle, 41.66% in buffalo, 30.55% in goats, 33.3% in sheep, and 33.3% in camels. Microscopic examination revealed slightly varied infection rates among large and small domestic animals (22.2%), while PCR results indicated a 32.8% overall infection rate in both large and small domestic animals, with no statistical significance. District-wise analysis showed regional variations, with Muzaffargarh recording a prevalence rate of 23.33% through microscopic examination, while Lodhran and Bahawalpur recorded 21.67%. PCR results revealed higher rates (38.33%, 26.67%, and 33.33%, respectively), underlining the importance of employing PCR for accurate detection. Examining ruminant types, large ruminants exhibited a 32.4% infection rate, while small domestic animals showed 33.3%, with no significant difference (p=0.897). District-wise prevalence showcased significant variation, with Muzaffargarh demonstrating a 25% prevalence, Lodhran 22%, and Bahawalpur 22%, through microscopic examination. PCR results displayed 38.33%, 27%, and 33.3%, respectively, with no statistical significance. Detailed analysis of individual districts highlighted variations in infection rates among camels, cattle, buffalo, goats, and sheep. The binomial test indicated significant differences through microscopic analysis (P=0.011) but non-significant variations through PCR (P=0.065), emphasizing the precision of PCR. Regional variations in prevalence, notably with Punjab exhibiting the highest frequency (33.87%) and KPK the lowest (13.24%), suggest potential influences from varying veterinary practices and environmental factors. This study underscores the pivotal role of PCR alongside microscopy for accurate babesiosis diagnosis. These findings contribute to the broader understanding of babesiosis prevalence, emphasizing the necessity of advanced molecular techniques for informed control measures.

Elucidating antiviral activity of Curcuma longa against H9 N2 influenza virus using embryonated chicken egg model

Curcumin is a potent antimicrobial herb used traditionally as a spice in culinary. This study was designed to evaluate the antiviral effects of curcuma longa extract against H₉ influenza virus. A total of 60 embryonated eggs were equally divided into 5 groups with 12 eggs in each group. Group 1 (G1) served as uninfected negative control. Whereas Group 2 (G2) was kept as positive control infected with known virus @ 0.2 ml with 10^-9.3 EID₅₀. Group 3 (G3) was offered Curcuma longa @ 0.2 mg/0.2 ml and H₉N₂ virus (@ 0.2 ml with 10^-9.3 EID₅₀. Similarly, Group 4 (G4) was inoculated with extract of Curcuma longa @ 0.2 mg/0.2 ml per egg, whereas Group 5 (G5) was given Ribazole @ 0.2 ml/ egg. The crude extract and virus were administered on the 15^th day of incubation and were checked after every 24 hours up to 96th hour post inoculation by random selection of 3 eggs. Death and survival rate were noted in all groups. Gross and histopathological lesions were also observed. Results revealed that Curcuma longa extract had significantly (p<0.05) reduced the mortality rate of embryos infected with H₉N₂ virus. In G3, increased lymphocytes and mild fatty changes were seen in liver. Whereas, mature RBCs, plasma cells and some lymphoblast's were observed in Spleen. Similarly, the bursa follicles were with lymphocytic aggregation. The G4 (Curcuma longa) and G5 (Ribazole) were with maximum embryo survival after 48 and 72 h post inoculation. This study revealed potential antiviral activity of Curcuma longa against H9N2 influenza viruses and can be opted as alternative to antibiotics and antiviral drugs to minimize the antimicrobial resistance in human and animal population.

Anaphylaxis: incidence, presentation, causes and outcome in patients in a tertiary-care hospital in Karachi, Pakistan

BACKGROUND

Anaphylaxis is a potentially fatal condition requiring immediate resuscitation. Data regarding the epidemiology of anaphylaxis are limited and inconsistent. A reason for the variability was unavailability of a universally acceptable case definition till 2005. We reviewed cases using this new definition

AIM

To review the incidence, clinical presentation, cause and outcome of anaphylaxis at a tertiary-care centre in a low-income country.

DESIGN

Retrospective, case series

METHODS

Chart review of all patients discharged from Aga Khan University Hospital between January 1988 and December 2012 (24 years) with anaphylaxis definition as per second National Institute of Allergy and Infection disease/Food Allergy and Anaphylaxis Network Symposium

RESULTS

Total of 129 cases were found with mean age of 41.6 years (SD 18.8). Majority of patients had cutaneous features (76.7%), followed by respiratory (68.9%), cardiac (64.3%) and gastrointestinal (20.9%) symptoms, respectively. About 22.4% of patients had positive history for allergens out of which 31% (n = 9) were exposed to the same allergens. The common causes identified for anaphylaxis were drugs (60.5%), food (16.3%) and intravenous contrast (10.9%), respectively. Only 22.5% of cases received epinephrine as a part of their initial management. In four patients (3.1%) the cause of death was attributed to anaphylaxis.

CONCLUSION

Anaphylaxis is a rare but life-threatening condition. Though cutaneous features are most common, their absence does not exclude the diagnosis. Drugs were the most common cause and epinephrine was not commonly used as first-line agent for its management.

Creating synergies for health systems strengthening through partnerships in Pakistan--a case study of the national eye health programme

Blindness and visual impairment are major causes of noncomrnunicable diseases in Pakistan. Two national population-based blindness surveys conducted in 1988 and 2002-04 demonstrated a reduction in prevalence of blindness from 1.78% to 0.9% with a significant drop in cataract blindness as a result of accelerated nationwide interventions and eye care integration in primary health care. In addition, between 2006 and 2008, 88 facilities were upgraded as a result of the national eye health programme. These measures resulted in a 279% increase in eye outpatient attendances and a 375% increase in eye surgeries performed. Investment in human resources development and policy change contributed significantly to the sustainability of the programme. Key challenges facing the programme include aligning national eye health strategies with health system strengthening informed through health systems research. This paper attempts to document this extraordinary success.

Prooxidant property of green tea polyphenols epicatechin and epigallocatechin-3-gallate: implications for anticancer properties

It is believed that anticancer and apoptosis inducing properties of green tea are mediated by it's polyphenolic constituents particularly catechins. A number of reports have shown that green tea polyphenol (-)-epigallocatechin-3-gallate (EGCG) is among the most effective chemopreventive and apoptosis-inducing agents present in the beverage. Plant polyphenols are naturally occurring antioxidants but they also exhibit prooxidant properties. Over the last several years we have shown that various classes of plant polyphenols including flavonoids, curcuminoids and tannins are capable of catalyzing oxidative DNA cleavage particularly in the presence of transition metal ions such as copper and iron. With a view to understand the chemical basis of various pharmacological properties of green tea, in this paper we have compared the prooxidant properties of green tea polyphenols--EGCG and EC ((-)-epicatechin). The rate of oxidative DNA degradation as well as hydroxyl radical and superoxide anion formation was found to be greater in the case of EGCG as compared with EC. It was also shown that copper mediated oxidation of EC and EGCG possibly leads to the formation of polymerized polyphenols. Further, it was indicated that copper oxidized catechins were more efficient prooxidants as compared with their unoxidized forms. These results correlate with the observation by others that EGCG is the most effective apoptosis inducing polyphenol present in green tea. They are also in support of our hypothesis that prooxidant action of plant polyphenols may be an important mechanism of their anticancer properties. A model for binding of Cu(II) to EC has been presented where the formation of quinone and a quinone methide has been proposed.

The biflavonoid, amentoflavone degrades DNA in the presence of copper ions

Previous reports from this laboratory have shown that flavonoids including apigenin are capable of inducing oxidative DNA cleavage in the presence of copper ions. In the present report, we have examined the ability of amentoflavone, a biflavonoid which is a dimer of apigenin, to catalyze the degradation of DNA. Amentoflavone was found to degrade calf thymus DNA in the presence of Cu(II) at a rate almost twice that of apigenin. Amentoflavone was also shown to reduce Cu(II) to Cu(I) and to generate hydroxyl radicals in the presence of copper ions. In the presence of Cu(II), the absorption spectrum of amentoflavone undergoes a shift and a quenching effect indicating that the biflavonoid is capable of binding to copper ions. Amentoflavone and apigenin were isolated from Cycas rumphii and Trifolium alexandrinum, respectively. The results are discussed in relation to the putative chemopreventive mechanism of amentoflavone.

Antioxidant and prooxidant properties of caffeine, theobromine and xanthine

BACKGROUND

Caffeine, along with its catabolic products theobromine and xanthine, is a key component of tea and coffee. These compounds are structurally similar to uric acid, a known antioxidant which is present in blood at relatively high concentrations, but also shows prooxidant activity. In view of the structural similarity between uric acid and caffeine and its metabolites, we studied the antioxidant and prooxidant properties of these compounds.

MATERIAL/METHODS

Antioxidant activity was determined by measuring the quenching effect of the compounds on oxidative DNA degradation by a hydroxyl radical generating system. Prooxidant activity was studied by measuring the ability of the compounds to oxidatively degrade DNA in the presence of copper ions.

RESULTS

Caffeine, theobromine and xanthine have a quenching effect on the production of hydroxyl radicals, as well as on oxidative DNA breakage by hydroxyl radicals. Consistent with previous observations that many known antioxidants of plant origin are also capable of prooxidant action, the purine alkaloids also show oxidative DNA breakage in the presence of transition metal ions.

CONCLUSIONS

The alkaloid caffeine and its catabolic products theobromine and xanthine exhibit both antioxidant and prooxidant properties. The results lead to the observation that caffeine and its metabolites may also contribute to the overall antioxidant and chemopreventive properties of caffeine-bearing beverages, such as tea.

Serotonin-Cu(II)-mediated DNA cleavage: mechanism of copper binding by serotonin

It has been proposed that considerable DNA damage may be caused by endogenous metabolites produced during the body's normal metabolic processes. 5-hydroxytryptamine (serotonin) is an important neurotransmitter in brain and spinal cord. We have previously shown that serotonin induces oxidative cleavage of DNA strands in the presence of copper ions. In the present paper we have examined the mechanism of copper binding by serotonin using absorption spectroscopy, Cu(II)-mediated lipid peroxidation and by determining the oxidation of the serotonin molecule. Addition of increasing concentrations of Cu(II) to serotonin leads to a progressive enhancement in the absorption band and is accompanied by a shift towards a lower wavelength indicative of the formation of an oxidised species of serotonin. Studies with the structurally related molecules tryptophan and melatonin showed that only serotonin is able to reduce Cu(II) to Cu(I). Similarly, only serotonin was found to be able to abolish the copper-mediated peroxidation of mitochondria. These results suggested the involvement of the phenolic group in copper binding. Further, it was also shown that the binding of copper to serotonin leads to the formation of a quinone in the absence of molecular oxygen. Based on these results, a model has been proposed in which serotonin reduces two molar equivalents of Cu(II) to Cu(I) through a reaction involving two electron oxidation of the phenolic ring to a quinone methide.

Potential antifilarial activity of the leaves and seeds extracts of Psoralea corylifolia on cattle filarial parasite Setaria cervi

The effect of aqueous and alcohol extracts of the leaves and seeds of Psoralea corylifolia, on the spontaneous movements of both the whole worm and the nerve muscle preparation of Setaria cervi and on the survival of microfilariae in vitro was studied. Alcohol extracts of both leaves and seeds caused the inhibition of spontaneous movements of the whole worm and the nerve muscle preparation of S. cervi, characterised by initial, short lasting small increase in tone of contractions followed by paralysis. The initial stimulatory effect was not observed by alcohol extract of leaves on nerve muscle preparation. The concentrations required to inhibit the movements of whole worm and nerve muscle preparations for alcohol extracts of leaves and seeds were 160, 30, and 150, 20 microg/ml, respectively suggesting a cuticular permeability barrier. Alcohol extracts of both leaves and seeds caused death of microfilariae in vitro, LC(50) and LC(90) being 15 and 25 ng/ml for alcohol extract of leaves and 12 and 18 ng/ml for alcohol extract of seeds, respectively.

Bleeding from the lung surface: a unique complication of off-pump CABG operation

A patient, with post myocardial infarction (MI) thrombolysis, underwent emergency off-pump coronary artery bypass graft. Her post-operative course was complicated by excessive bleeding. At re-exploration, the bleeding was caused by a graze on the lung surface by the needle used during the insertion of the deep pericardial retraction suture.

Oxidative DNA damage by capsaicin and dihydrocapsaicin in the presence of Cu(II)

Capsaicin is the pungent phenolic principle of the Capsicum species, and has shown a wide range of pharmacological properties, including antigenotoxic, antimutagenic, and anticarcinogenic effects. Other studies have, however, shown it to be a tumor promoter and potential mutagen, and a carcinogen, resulting in capsaicin being termed a 'double edged sword'. In the present study, we show that capsaicin is capable of causing strand scission in calf thymus and plasmid DNA in the presence of Cu(II) and that this breakage is mediated by reactive oxygen species, especially the hydroxyl radical. Our results further show that capsaicin can directly generate hydroxyl radicals in the presence of Cu(II). To explore the chemical basis of the DNA breakage reaction by capsaicin, we have compared these properties of capsaicin with its saturated structural analog dihydrocapsaicin (DHC). The rate of DNA degradation, as well as hydroxyl radical formation, was found to be greater in the case of capsaicin. Both capsaicin and DHC are able to reduce Cu(II) to Cu(I), which was shown to be an essential intermediate in the DNA cleavage reaction. Stoichiometric analysis indicated that whereas 1 mol of capsaicin reduced 3 mol of Cu(II), 1 mol of DHC reduced only 2 mol of Cu(II). This explains the greater activity of capsaicin and also leads to a model for copper binding to the capsaicins.

Prooxidant and antioxidant activities of bilirubin and its metabolic precursor biliverdin: a structure-activity study

Bilirubin, which is derived from its metabolic precursor biliverdin, is the end product of heme catabolism. It has been proposed as a physiological antioxidant present in human extracellular fluids. We have earlier shown that bilirubin in the presence of the transition metal ion Cu(II) causes strand cleavage in DNA through generation of reactive oxygen species, particularly the hydroxyl radical. Thus bilirubin possesses both antioxidant and prooxidant properties. In order to understand the chemical basis of various biological properties of bilirubin, we have studied the structure-activity relationship between bilirubin and its precursor biliverdin. The latter has also been reported to possess both antioxidant and toxic properties. In the present studies bilirubin was found to be more effective in the DNA cleavage reaction and a more efficient reducer of Cu(II). The rate of formation of hydrogen peroxide and hydroxyl radicals by the compounds also showed a similar pattern. The relative antioxidant activity was also examined by studying the effect of these compounds on DNA cleavage by a hydroxyl radical generating system and their quenching effect on hydroxyl radicals. The results indicate that bilirubin is more active both as an antioxidant as well as an oxidative DNA cleaving agent. A model for binding of copper to bilirubin has been proposed where two copper ions are bound to two molecules of bilirubin through their terminal pyrrole nitrogens. In order to account for the enhanced copper reducing capacity of bilirubin we have further proposed that an additional copper binding site is provided for in the case of bilirubin due to the absence of a double bond between pyrrole rings II and III. Further it would appear that the structural features of the bilirubin molecule which are important for its prooxidant action are also the ones that render it a more effective antioxidant.

Exploration of antifilarial potential and possible mechanism of action of the root extracts of Saxifraga stracheyion on cattle filarial parasite Setaria cervi

The effect of aqueous and alcohol extracts of the roots of Saxifraga stracheyi Engl. On the spontaneous movements of both the whole worm and the nerve muscle preparation of Setaria cervi and on the survival of microfilariae in vitro was studied. Both extracts caused the inhibition of spontaneous movements of the whole worm and the nerve-muscle preparation of S. cervi, characterized by an increase in the amplitude and a decrease in the rate of contractions, while the tone of the contractions remained visibly unaffected. The concentration required to inhibit the movements of the whole worm preparation was 140 microg/ml for the aqueous and 250 microg/ml for the alcohol extract. The concentration of S. stracheyi extracts required to produce an equivalent effect on the nerve-muscle preparation was 30 microg/ml for aqueous, and 20 microg/ml for the alcohol extract, suggesting a cuticular permeability barrier.

Reactivities of flavonoids with different hydroxyl substituents for the cleavage of DNA in the presence of Cu(II)

DNA strand scission reactions of flavonoids in the presence of Cu(II) have been extended by using flavonoids with a variety of patterns of hydroxyl substitution. In particular we have examined for the first time a flavonoid (7,8-dihydroxyflavone) that lacks the possibility of forming a complex involving the oxygen at position 4. By comparing the reactivities of several flavonoids, including data from the literature, we draw generalizations for the correlation of structure and activity and present evidence for at least three different modes of action of flavonoids as genotoxic agents.

Pro-oxidant, anti-oxidant and cleavage activities on DNA of curcumin and its derivatives demethoxycurcumin and bisdemethoxycurcumin

Curcumin, a naturally occurring phytochemical responsible for the colour of turmeric shows a wide range of pharmacological properties including antioxidant, anti-inflammatory and anti-cancer effects. We have earlier shown that curcumin in the presence of Cu(II) causes strand cleavage in DNA through generation of reactive oxygen species, particularly the hydroxyl radical. Thus, curcumin shows both antioxidant as well as pro-oxidant effects. In order to understand the chemical basis of various biological properties of curcumin, we have studied the structure-activity relationship between curcumin and its two naturally occurring derivatives namely demethoxycurcumin (dmC) and bisdemethoxycurcumin (bdmC). Curcumin was found to be the most effective in the DNA cleavage reaction and a reducer of Cu(II) followed by dmC and bdmC. The rate of formation of hydroxyl radicals by the three curcuminoids also showed a similar pattern. The relative antioxidant activity was examined by studying the effect of these curcuminoids on cleavage of plasmid DNA by Fe(II)-EDTA system (hydroxyl radicals) and the generation of singlet oxygen by riboflavin. The results indicate that curcumin is considerably more active both as an antioxidant as well as an oxidative DNA cleaving agent. The DNA cleavage activity is the consequence of binding of Cu(II) to various sites on the curcumin molecule. Based on the present results, we propose three binding sites for Cu(II). Two of the sites are provided by the phenolic and methoxy groups on the two benzene rings and the third site is due to the presence of 1,3-diketone system between the rings. Furthermore, both the antioxidant as well as pro-oxidant effects of curcuminoids are determined by the same structural moieties.

Antifilarial activity of Mallotus philippensis Lam. on Setaria cervie (Nematoda: Filarioidea) in vitro

The effect of aqueous and alcoholic extracts of the leaves of Mallotus philippensis (Lam.) Muell. Arg. was studied on the spontaneous movements of the whole worm and nerve-muscle (n.m.) preparation of Setaria cervi and on the survival of microfilariae in vitro. Both the extracts caused inhibition of spontaneous motility of whole worm and the n.m. preparation of S. Cervi characterized by initial stimulation followed by depression in amplitude. The tone and rate of contractions remained visibly unaffected. Aqueous extract at higher concentration showed immediate reduction in tone. The concentration required to inhibit the movements of n.m. preparation was 1/5th for aqueous and 1/11th for alcoholic extract compared to that for the whole worm, suggesting a cuticular permeability barrier. The stimulatory response of acetylcholine was blocked by aqueous extract on whole worm movements. On the microfilariae the LC50 and LC90 were 18 and 20 ng/ml for aqueous and 12 and 15 ng/ml for alcoholic extracts respectively.

Potential antifilarial activity of roots of Asparagus adscendens Roxb, against Setaria cervi in vitro

Effect of aqueous and alcoholic extracts of the roots of A. adscendens was studied on the spontaneous movements of whole worm and nerve muscle (n.m.) preparation of S. cervi and on the survival of microfilariae in vitro. Aqueous as well alcoholic extracts caused inhibition of spontaneous motility of whole worm and n.m. preparation of S. cervi characterized by initial, short lasting small increase in amplitude and tone of contractions followed by paralysis. The initial stimulatory effect was not observed by aqueous extract on n.m. preparation. The concentration required to inhibit the movements of n.m. preparation was 1/4th for aqueous and 1/3rd for alcoholic extract suggesting a cuticular permeability barrier. The effect of acetylcholine on n.m. preparation was concentration related being more with a concentration of 5 micrograms/ml as compared to 1 microgram/ml. Both alcoholic as well as aqueous extracts caused death of microfilariae in vitro, LC50 and LC90 being 8 and 16 ng/ml for aqueous, 3 and 12 ng/ml for alcoholic extracts respectively.

In vitro antifilarial activity of Sencio nudicaulis Buch. Ham. Effect on Setaria cervi (Nematoda Filarioidea)

The effect on aqueous and alcoholic extracts of the leaves of Sencio nudicaulis Buch. Ham. was studied on the spontaneous movements of the whole worm and nerve-muscle preparation of Setaria cervi and on the survival of micro-filariae in vitro. Aqueous as well as alcoholic extracts caused inhibition of spontaneous motility of the whole worm and nerve-muscle preparation of S. cervi characterized by decreased amplitude, rate and tone of contractions. The concentration required to inhibit the movements of n.m. preparation was 1/3rd for aqueous and 1/20th for alcoholic extract suggesting a cuticular permeability barrier. The effect of S nudicaulis extracts was different than that produced by calcium channel blocker nifedipine on the whole worm and n.m. preparation. While nifedipine blocks the stimulant effect of Ach the extracts of S. nudicaulis fails to do so. While the response bears similarity with DEC which also does not block Ach response. Both aqueous and alcoholic extracts exhibited microfilaricidal action in vitro LC50 and LC90 being 10 and 15 ng/ml for aqueous extract, 5 and 12 ng/ml for alcoholic extract.

Experience with frontonasal dysplasia of varying severity

Nine cases of frontonasal dysplasia were seen during an 8-year period. Seven were managed in the authors' institution, and the two adult relatives were referred to adult units. The age and sex distribution, the types of defects, and the family pedigree of an affected family are described. Management criteria were formulated according to the severity and other associated abnormalities.

The distribution of immunoreactive interferon-gamma-containing cells in normal human tissues

An immunohistochemical technique has been used to study the distribution of lymphocytes expressing interferon-gamma in normal adult tissues. The greatest concentrations of these cells were seen in mucosal sites exposed to a resident microflora. It is proposed that such organisms, by eliciting immune responses, provide the stimulus for the production of 'physiological' interferon-gamma. This in turn may act to preserve the 'tone' or readiness of the immune system.

The distribution of immunoreactive interferon-alpha in formalin-fixed paraffin-embedded normal human foetal and infant tissues

Human foetal and infant tissues were studied to test the hypothesis that microbes have a role in switching on interferon-alpha (IFN-alpha) synthesis. Foetal tissues were essentially 'germ free', while the infants had been exposed to a normal microbial environment in life. IFN-alpha was first seen at 9 weeks gestation in macrophages in the liver and thereafter was seen in macrophages in most other organs. When infant lungs were compared with foetal lungs, a statistically significant increase in the number of macrophages and the percentage of these cells expressing IFN-alpha was noted in the infant lungs. No such change was observed in spleen, liver and thymus following birth. These findings suggest that there is a basal production of IFN-alpha by macrophages that is not dependent on microbial products, but that such products can enhance synthesis of this cytokine.

Sex differences and sustained excess in mortality among discordant twins in Matlab, Bangladesh: 1977-1985

This paper reports findings from a study that compared survival of 204 pairs of liveborn twins discordant for sex and a random sample of 2371 singleton live births from the same population in Matlab, Bangladesh during the period 1977-1985. The discordant twins showed no evidence of sex differential in neonatal survival. They had neonatal mortality of 287 and infant mortality of 468, both per 1000 live births. These rates were respectively five and four times the rate for singletons in the study. Survival from 12 months through age nine years was similar overall for both discordant twins and singletons for each sex. However, higher female than male mortality was present among discordant twins after the first few months of life. This differential was most prominent during the second year of life and appeared wider than that observed for the singletons.

The distribution of immunoreactive interferon-alpha in normal human tissues

The cellular distribution of immunoreactive interferon-alpha (IFN-alpha) was studied in formalin-fixed paraffin-embedded normal human tissues from 36 different organs. These samples were drawn from over 300 individuals none of whom had evidence of viral infection. Tissue histiocytes from all organs in the body, with the exception of brain and renal cortex and medulla, stained positively for IFN-alpha. Kupffer cells, pulmonary alveolar macrophages and lymph node macrophages were also positive. Parenchymal cells in some other organs also appeared to contain immunoreactive IFN-alpha. These included cuboidal lining cells of the choroid plexus in the brain, thyroid follicular cells, pituitary endocrine cells, adrenocortical cells and parathyroid principal and oxyphil cells. These findings are compatible with previous suggestions that IFN-alpha may be synthesized and released in the absence of viral infection and may thus have a role in normal physiology. The presence of IFN-alpha in most cells of the mononuclear phagocyte system suggests that these cells may play a major part in defence against viral infection.

Study of interfering substances in a simple, new spectrophotometric assay for phenylalanine ammonia-lyase

A study of interfering substances in a new spectrophotometric assay for phenylalanine ammonia-lyase has been made. None of the commonly interfering compounds interfere in the assay to any significant extent. The assay has been employed for the partial purification of the enzyme from mint leaves (Mentha viridis'L).