Psidium guajava: An Insight into Ethnomedicinal Uses, Phytochemistry, and Pharmacology

BACKGROUND

Psidium guajava (guava) is widely distributed in tropical and subtropical regions and adapted to various environmental conditions. Guava is an important economic fruit widely used as food and folk medicine. It contains flavonoids, alkaloids, tannins, triterpenoids, reducing sugars, essential oils, carotenoids, polyphenols, etc. The presence of triterpenoid acids such as guavacoumaric, ursolic, jacoumaric, guajavanoic, guavenoic, and Asiatic acids helps to develop novel drugs against various diseases. It is used traditionally for medicinal purposes, mainly for antioxidant, antimicrobial, antispasmodic, antidiabetic, anticancer, antiallergy, anti-inflammatory, and hepato-protective properties.

OBJECTIVE

The systematic literature study aims to summarize its botanical description, phytochemicals, pharmacological activities, and clinical trials. This review focuses on the plant's chemical composition and scientific approaches to human welfare.

METHODS

A systematic literature search was done on Psidium guajava through previous literature and online databases such as Google Scholar, Pubmed, Science Direct, etc., to explain its ethnomedicinal uses, phytochemistry, and pharmacological applications.

RESULTS

Previous literature studies of Psidium guajava suggest it can serve as antioxidant, antimicrobial, antispasmodic, antidiabetic, anticancer, anti-allergy, anti-inflammatory, and hepatoprotective effects. Successful clinical trials performed on the plant extracts against infantile rotaviral enteritis and infectious gastroenteritis showed future directions to work with the plant for clinical applications.

CONCLUSION

In this review, an attempt is made to show all literature studied, especially in phytochemistry, pharmacology, clinical trials and uses as traditional folk medicine around the world. The leaves have been used by folklore over the years to treat various ailments such as skin ulcers, diarrhoea, vaginal irritation, cough, conjunctivitis, etc. Further studies are required to explore more therapeutic remedies and to develop new medicines for future perspectives.

Madhuca indica: A Review on the Phytochemical and Pharmacological Aspects

Madhuca indica J.F. Gmel. (family: Sapotaceae), commonly known as Mahua in Indian dialects, occupies the importance as one of the fuel-efficient, energy-saving plant species. Extensive studies showed that the presence of phytochemicals e.g., carbohydrates, fatty acids, flavonoids, saponins, steroids, triterpenoids and glycosidic compounds in the extract of this species. Pharmacologically, it has been used against various disorders in indigenous system of medicine, inckuding antioxidant, anti-inflammatory, anticancer, hepatoprotective, anti-diabetic and wound healing activities. This review highlights various pharmacological activities, phytochemistry and importance of M. indica plant for medicine.

Cold Pressor Test in Borderline Hypertensive University Students

Background Hyperactive sympathetic reaction is an important factor for development of hypertension in young individuals. The stress induced increase in blood pressure recovers within very short period of time and those with exaggerated stress induced cardiovascular response at young age have a high risk of blood pressure elevation in future. Objective To determine the cardiovascular reactivity in response to cold and to correlate its relation with factors such as smoking, family history and physical activity. Method Study was conducted in the Department of Pharmacy, Kathmandu University from July to November, 2015. Resting blood pressure was recorded using sphygmomanometer in sitting position after 5 minutes of rest. Out of 130 volunteers, 34 were found to be prehypertensive and equal number of normotensive were recruited randomly to perform the test. The subjects were directed to immerse his/her right hand up to the wrist in cold water of 10˚C for 1 minute. The blood pressure was recorded just before the hand was taken out of the water and then 1.5 minutes and 4 minutes after the withdrawal. Data was analyzed by Student's t test using Microsoft Excel 2007. Result Systolic and diastolic blood pressure increased significantly after cold pressor test in both normal (systolic blood pressure from 110±6.46 to 119±9.45 mmHg and diastolic blood pressure from 71±4.63 to 78±6.15 mmHg) and prehypertensive group (systolic blood pressure from 122±6.75 to 126±8.05 mmHg and diastolic blood pressure from 79±6.78 to 85±7.76 mmHg). Maximum recovery in both systolic and diastolic blood pressure was observed in 2.5 minutes of removal of hand from cold water. Though sharp drop was observed in blood pressure at the end of 2.5 minute in both groups of individuals, the recovery in case of prehypertensive individual was not sharper. In the present study, significant rise in diastolic blood pressure was observed in prehypertensive smoking males. Also the difference was significant (p<0.02) in recovery of diastolic blood pressure between smoker and non smoker prehypertensive group. Conclusion This study suggests that prolonged elevation in blood pressure in response to stress in young individual can be used as marker of development of hypertension in future. Adopting a healthier lifestyle can help to delay the development of hypertension in later life.

Bone marrow lesions, subchondral bone cysts and subchondral bone attrition are associated with histological synovitis in patients with end-stage knee osteoarthritis: a cross-sectional study

OBJECTIVE

The aim of this study was to examine the osteoarthritis (OA)-related structural changes associated with histological synovitis in end-stage knee OA patients.

METHODS

Forty end-stage knee OA patients (female: 88%, mean age: 71.8 y) were enrolled. All participants underwent 3.0-T MRI. The structural changes, such as cartilage morphology, subchondral bone marrow lesion (BML), subchondral bone cyst (SBC), subchondral bone attrition (SBA), osteophytes, meniscal lesion and synovitis, were scored using the whole-organ MRI scoring (WORMS) method. Synovial samples were obtained from five regions of interest (ROIs) of the knee joint during total joint replacement surgery. The associations between the histological synovitis score (HSS) and WORMS or the synovial expression levels of cyclooxygenase (COX)-2, interleukin (IL)-1β, IL-6 and transforming growth factor (TGF)-β were examined using Spearman's correlation coefficient.

RESULTS

Among the seven OA-related structural changes, the BML, SBC, SBA and synovitis were significantly associated with the HSS (r = 0.33, 0.35, 0.48 and 0.36, respectively), while other morphological changes were not. Although synovial COX-2, IL-1β or IL-6 expression levels were not associated with the HSS, the synovial TGF-β expression levels were associated with the HSS.

CONCLUSION

The presence of BML, SBC and SBA was associated with histological synovitis in end-stage knee OA patients.

The degeneration and destruction of femoral articular cartilage shows a greater degree of deterioration than that of the tibial and patellar articular cartilage in early stage knee osteoarthritis: a cross-sectional study

OBJECTIVE

The aim of the present study was to examine whether the degenerative and morphological changes of articular cartilage in early stage knee osteoarthritis (OA) occurred equally for both femoral- and tibial- or patellar- articular cartilage using magnetic resonance imaging (MRI)-based analyses.

DESIGN

This cross-sectional study was approved by the ethics committee of our university. Fifty patients with early stage painful knee OA were enrolled. The patients underwent 3.0 T MRI on the affected knee joint. Healthy volunteers who did not show MRI-based OA changes were also recruited as controls (n = 19). The degenerative changes of the articular cartilage were quantified by a T2 mapping analysis, and any structural changes were conducted using Whole Organ Magnetic Resonance Imaging Score (WORMS) technique.

RESULTS

All patients showed MRI-detected OA morphological changes. The T2 values of femoral condyle (FC) (P < 0.0001) and groove (P = 0.0001) in patients with early stage knee OA were significantly increased in comparison to those in the control, while no significant differences in the T2 values of patellar and tibial plateau (TP) were observed between the patients and the control. The WORMS cartilage and osteophyte scores of the femoral articular cartilage were significantly higher than those in the patellar- (P = 0.001 and P = 0.007, respectively) and tibial- (P = 0.0001 and P < 0.0001, respectively) articular cartilage in the patients with early stage knee OA.

CONCLUSIONS

The degradation and destruction of the femoral articular cartilage demonstrated a greater degree of deterioration than those of the tibial- and patellar- articular cartilage in patients with early stage knee OA.

The factors associated with pain severity in patients with knee osteoarthritis vary according to the radiographic disease severity: a cross-sectional study

OBJECTIVES

Knee osteoarthritis (OA) pain is suggested to be associated with inflammation and detrimental mechanical loading across the joint. In this cross-sectional study, we simultaneously examined the inflammation and alignment of the lower limb and examined how the pain components varied depending on the disease progression.

DESIGN

One-hundred sixty female medial type of early- [n = 74 in Kellgren-Lawrence (K/L) 2] to advanced-stage (n = 96 in K/L >2) knee OA subjects (70.5 years on average) were enrolled. Knee pain was evaluated using a pain visual analog scale (VAS) and the pain-related subcategory of the Japanese Knee Osteoarthritis Measure (JKOM-pain). The serum interleukin (sIL)-6 level reflecting synovitis, and the high sensitivity C-reactive protein (hs-CRP) level were measured to evaluate the severity of inflammation. The anatomical axis angle (AAA) was measured as an alignment index. The β-coefficient was estimated after adjusting for age and the body mass index (BMI) using a multiple linear regression analysis.

RESULTS

Multiple linear regression analyses showed that the sIL-6 levels, but not AAA, associated with the pain VAS [β = 10.77 (95% confidence interval (CI): 4.14-17.40), P < 0.01] and JKOM-pain scores [β = 3.19 (95% CI: 1.93-4.44), P < 0.001] in the early stage. Conversely, AAA, but not the sIL-6 levels, was found to be associated with the pain VAS [β = -1.29 (95% CI: -2.51 to -0.08), P < 0.05] and JKOM-pain scores [β = -0.49 (95% CI: -0.82 to -0.16), P < 0.01] in the advanced stage.

CONCLUSIONS

The presence of a higher level of sIL-6 and the varus alignment of the joint is associated with pain in early- and advanced-stage knee OA patients, respectively.

Prevalence of intestinal worm infestations among school children in Kathmandu, Nepal

Intestinal worm infestation is one of the major childhood health problem in Nepal. This study was done to assess the prevalence of intestinal worm infestations among school children aged 6-16 years in a public high school in Kathmandu Nepal. A total of 142 stool samples from healthy students were collected and reported following formol-ether concentration technique. The overall prevalence of intestinal worm infestation was found to be 17.6% (Boys = 22.0% vs girls = 13.5%). Children aged 6-8 years were found to be highly infected with intestinal worms (21.4%) followed by 9-12 years old (18.6%). Those between 13-16 years of age were significantly less infected (10.7%) compared to others (p < 0.05). Ova/cysts of intestinal parasites detected include Trichuris trichiura (32.0%), Ascaris lumbricoides (20.0%), Hymenolepis nana (16.0%), hookworm (8.0%) and 24.0% cases showed mixed parasitic infections.

Diagnostic methods of malaria in Eastern Nepal: a comparative study of traditional and two rapid diagnostic tests

This study compared the diagnostic accuracy of Quantitative Buffy Coat (QBC) a fluorescent microscopy test and OptiMAL, an immunochromatographic dip stick test against conventional microscopy for the detection of malaria at a tertiary teaching hospital situated in Eastern Nepal. 100 clinically suspected malaria patients with positive and negative parasitemia were assessed under conventional microscopy. The blood samples withdrawn from these subjects were further evaluated by the QBC Method and OptiMAL dipstick test. The sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy of QBC and OptiMAL tests as compared with microscopy were 100%, 100%, 100%, 100%, 1 and 96%, 100%, 100%, 96.15% and 0.98 respectively. In Nepal, thick and thin blood smears remain the gold standard for malaria species diagnosis in routine diagnostic laboratories. In this study the efficacy of newer malaria rapid diagnostic tests (RDT) surpassed the diagnostic efficacy of clinical microscopy and hence these RDT's will have a greater role in clinical practice. The cost of QBC technique may impose limitations on its use in Nepal but the OptiMAL test is likely to play an important part in urgent malaria diagnosis.

A novel infant acute lymphoblastic leukemia cell line with MLL-AF5q31 fusion transcript

Infant acute lymphoblastic leukemia (ALL) is characterized by the presence of the proB phenotype (CD10(-)/CD19(+)), poor prognosis and frequent rearrangement of the mixed lineage leukemia (MLL) gene. The most frequent rearrangement is t(4;11)(q21;q23), the role of whose product, the MLL-AF4 fusion transcript, has been extensively studied in leukemogenesis. In a cell line of infant leukemia with MLL rearrangement denoted KP-L-RY, panhandle PCR amplification of cDNA revealed the presence of a fusion transcript, MLL-AF5q31, indicating that AF5q31 is also a partner gene of MLL. In this fusion transcript the MLL exon 6 is fused in frame to the 5' side of the putative transactivation domain of AF5q31. The AF5q31 protein is a member of the AF4/LAF4/FMR2-related family of proteins, which have been suggested to play a role in hematopoietic cell growth and differentiation. The MLL-AF5q31 fusion transcript, although probably rare, appears to be associated with the pathogenesis of infant ALL like MLL-AF4. Co-expression of HoxA9 and Meis1 genes in the KP-L-RY cell line indicated possible functional similarity between MLL-AF4 and MLL-AF5q31. Further understanding of the function of AF5q31 as well as the specific leukemogenic mechanism of MLL-AF5q31 awaits future studies.

Transient shrinkage of a uterine leiomyosarcoma treated with GnRH agonist for a presumed uterine leiomyoma: comparison of magnetic resonance imaging finding before and during GnRH agonist treatment

We present a case of a premenopausal woman treated with GnRH agonist for a presumed uterine leiomyoma. This tumor reduced at first, but subsequent surgical specimens revealed a leiomyosarcoma. Magnetic resonance imaging (MRI), one of the most useful modalities for distinguishing between uterine leiomyoma and leiomyosarcoma, was undertaken twice, before GnRH agonist administration and then after 6 months of GnRH agonist administration. Apparent differences were observed between these MRI findings. Tumor-size reduction with GnRH agonist treatment does not always mean that the possibility of a leiomyosarcoma should be ruled out.

Development of spectral colour banding in cytogenetic analysis

We developed a novel chromosome banding technique-spectral colour banding (SCAN). With this technique we displayed a multicolour banding pattern that almost entirely correlated with the corresponding G-banding pattern. With SCAN analysis we could identify the chromosome-band origin of double minute chromosomes in gastric cancer. Our preliminary use of this technique suggests that it has significant clinical applications for cytogenetic analysis.

Ultraviolet spectroscopic estimation of microenvironments and bitter tastes of oxyphenonium bromide in cyclodextrin solutions

The UV absorbance and bitter taste of oxyphenonium bromide (OB), an antiacetylcholine drug, in cyclodextrin (CD) solutions are measured, and the local environment of the binding site and the reduction of the bitter taste intensity are quantitatively estimated from the UV data. The UV spectrum of OB is changed with the addition of alpha-, beta-, and gamma-CD, because the phenyl group of OB is included into the CD cavity. The maximum wavelength, lambda(max), senses environmental changes of OB best among several spectral characteristics. From comparison of lambda(max) between a CD solution and the reference ethanol-water and dioxane-water systems, the dielectric constant of the binding site is evaluated. This value leads us to estimate the microenvironment and structure of the binding site. The suppression of the bitter taste of 4 mM OB by CDs is in the increasing order alpha-CD < gamma-CD < beta-CD. The extent of this suppression can be quantitatively predicted from the UV absorbance by assuming that the free OB molecule alone exhibits the bitter taste, regardless of the kind and concentration of CD. Some implications and limitations of the present approach are discussed.

Two separate episodes of hemophagocytic syndrome at a two-year interval in an apparently immunocompetent male

We describe two separate episodes of hemophagocytic syndrome (HPS) at an interval of two years in a seemingly immunocompetent male. This case suggests the possible existence of an inherent predisposition to HPS, in which otherwise negligible self-limited viral infection may trigger HPS. Laboratory data for a 16-year-old boy admitted with persistent high grade fever and severe thrombocytopenia disclosed coagulation abnormality, liver damage, and hypercytokinemia. A bone marrow aspiration revealed a proliferation of histiocytes with fresh hemophagocytosis. We diagnosed that he was suffering from HPS. Responding to steroid pulse therapy, he recovered completely and was discharged. After two years of healthy life, he became febrile again and was readmitted. The fever was refractory to antibiotics and was associated with a sudden drop in platelet count. Laboratory data and the bone marrow picture were consistent with those of HPS. He was again successfully treated with steroid. After the second episode, he has been healthy for more than two years.

Hemophagocytic syndrome in five patients with Epstein-Barr virus negative B-cell lymphoma

BACKGROUND

The recent recognition of the association of Epstein-Barr virus (EBV) with T-cell/natural killer cell (T/NK-cell) lymphoma has documented that particular types of EBV-containing T/NK-cell lymphoma are frequently complicated by hemophagocytic syndrome (HPS). This observation suggests that both EBV and proliferating T/NK-lymphoma cells play significant roles in the development of HPS. Cytokines released from neoplastic T cells are presumed to account for the activation of macrophages, which is followed by a complex cascade of cytokine production, resulting in full-blown HPS. Five patients with B-cell lymphoma complicated by HPS were studied for elevated serum cytokines, the association of EBV, and CD25 expression of lymphoma cells; the aim of this study was to verify whether the mechanisms of HPS development hypothesized for T/NK-cell lymphoma also operate in B-cell lymphoma.

METHODS

Sera were analyzed for the presence of inflammatory and immunoregulatory cytokines. Flow cytometry, immunohistology (IH), in situ hybridization (ISH), polymerase chain reaction (PCR), and Southern blot analysis were performed using bone marrow aspirates, biopsy specimens, and autopsy specimens.

RESULTS

Immunophenotypic and Southern blot studies verified that the lymphoma cells of all five patients were of B-cell lineage. Bone marrow aspirates demonstrated histiocytosis with extensive hemophagocytic activity. Marked elevation of serum cytokines and expression of CD25 were observed in all five patients. However, the results of PCR, ISH using EBER1 probe, and IH for latent membrane protein indicated that these lymphoma cells were free of EBV infection.

CONCLUSIONS

In patients with B-cell lymphoma, EBV infection is not necessarily required for the initiation of HPS. In this article, the pathogenesis of HPS assumed to be operative in B-cell lymphoma is discussed with reference to T/NK-cell lymphoma complicated by HPS.

Chronic myeloid leukemia with minor-bcr breakpoint developed hybrid type of blast crisis

Although a breakpoint in the minor breakpoint cluster region (m-bcr) of the BCR gene is observed in about two-thirds of patients with Philadelphia chromosome-positive acute lymphoblastic leukemia, this type of genomic rearrangement occurs very rarely in chronic myeloid leukemia (CML). We describe here the eighth case of m-bcr CML, and delineate unique clinical characteristics found in common to the 7 cases reported previously. Monocytosis with a low neutrophil/monocyte ratio resembling chronic myelomonocytic leukemia was the most striking feature of m-bcr CML. Splenomegaly and basophilia were not conspicuous in chronic phase. A high percentage of immature granulocytes and low neutrophil alkaline phosphatase score were the findings in common with classical CML. Lymphoid and myeloid blast changes have been observed at and shortly after presentation so far. We found a hybrid type of blast crisis in the course of m-bcr CML.Thus, m-bcr CML may be a definite subtype of CML, exhibiting distinct clinical characteristics. The presence of fusion product of m-bcr mRNA in an earlier myeloid cell may involve monocytic lineage in addition to myeloproliferative defects.

Chemical modification and inactivation of phospholipases A2 by a manoalide analogue

Chemical modification and inactivation of bovine pancreatic, porcine pancreatic, Naja naja atra and Pseudechis australis phospholipases A2 (PLA2s), belonging to Group I, and of Trimeresurus flavoviridis, Vipera russelli russelli and Agkistrodon halys blomhoffii PLA2s, belonging to Group II, were investigated by the use of a manoalide (MLD)-analogue, 1-(2,5-dihydro-hydroxy-5-oxo-3-furanyl)-8,12-dimethyl-4-formyl-3,7, 11-tridecatrienol. At appropriate time intervals, residual PLA2 activities towards monodispersed, anionic mixed micellar and non-ionic mixed micellar substrates were measured. We tested the protective effect of micellar n-dodecylphosphocholine (n-C12PC) on enzyme inactivation. Inactivation of pancreatic PLA2s (Group I) was only observed towards anionic mixed micellar substrates. This inactivation was completely prevented by the presence of micellar n-C12PC. From a fragmentation study of modified bovine pancreatic PLA2 using lysyl endopeptidase, we speculated that Lys-56 of this enzyme was modified by MLD-analogue and that this modification was responsible for enzyme inactivation. Inactivation of non-pancreatic PLA2s was observed towards all types of substrate, except that no significant inactivation of N. naja atra PLA2 (Group I) towards monodispersed substrate was noted. Micellar n-C12PC protected N. naja atra PLA2 (Group I) completely from inactivation by MLD-analogue, but had lesser protective effects on P. australis PLA2 (Group I), T. flavoviridis and V. russelli russelli PLA2s (Group II). However, no significant protection of A. halys blomhoffii PLA2s (Group II) activity was observed. These results indicate that the inactivation of pancreatic and N. naja atra PLA2s originates from the modification of Lys residues at the interfacial recognition site, and that inactivation of P. australis, T. flavoviridis and V. russelli PLA2s arises from the modification of Lys residues at the catalytic site, interfacial recognition site and regions outside both sites. The inactivation of A. halys blomhoffii PLA2 was assumed to be due to the modification of Lys residues outside the two sites described above.

Role of Ca2+ in the binding of phospholipase A2 with a monomeric substrate and with its amide-type analog

Effects of Ca2+ on the kinetic parameters for the hydrolysis of monodispersed 1,2-dihexanoyl-sn-glycero-3-phosphorylcholine (diC6PC), catalyzed by Group I phospholipases A2 (PLA2s) from Pseudechis australis, Naja naja atra, and bovine pancreas and by Group II enzymes from Vipera russelli russelli, Agkistrodon halys blomhoffii, and Trimeresurus flavoviridis, were studied by the pH-stat assay method at 25 degrees C, pH 7.5-8.2, and an ionic strength of 0.1 or 0.2 in the absence or presence of an amide-type substrate analog, 2-dodecanoyl-amino-1-hexanol-phosphoglycol. The binding of genuine substrate to the Group II enzymes and that of its analog to the Groups I and II enzymes were markedly facilitated by the binding of Ca2+ to the enzymes. On the other hand, the binding of genuine substrate to the Group I enzymes was found to be independent of the Ca2+ binding. The former result suggests that the structures of the Group II enzyme-genuine substrate complexes and both types of enzyme-analog complexes are generally stabilized by the Ca2+ binding, whereas the latter indicates that the structures of the Group I enzyme-genuine substrate complexes are already similar to those of their Ca2+ complexes and that, therefore, these enzyme-substrate interactions are independent of the Ca2+ binding.

[Measurement of platelet thromboxane A2/prostaglandin H2 receptor in asthmatic patients]

To evaluate the characteristics of platelet TXA2/PGH2 receptors in patients with bronchial asthma, we performed radiobinding assay of gel-filtrated washed platelets obtained from 15 asthmatic patients and 8 normal adults using [3H]-labeled S-145, a TXA2/PGH2 receptor antagonist, as a radiolinged. Data were evaluated by Schatchard's analysis, and the dissociation constant (Kd), an index of the binding characteristic of receptors, and the maximum number of binding sites (Bmax) were calculated. Venous blood was simultaneously collected and was centrifuged, and platelet-rich plasma was prepared. The platelet aggregation rates induced by various concentrations of U-46619, a TXA2 analogue, were measured by Born's method (nephelometry), and the concentration that induced 50% of the maximum platelet aggregation (EC50) was calculated using a concentration-response curve. The Kd value did not differ between the asthmatic patients and normal controls. Some of the asthmatic patients showed a low EC50 and a high Bmax. EC50 was inversely correlated with Bmax. The number of platelet TXA2/PGH2 receptors was shown to be increased in some asthmatic patients.

Antithrombotic effect of an anti-glycoprotein IIB/IIIA antibody in primate lethal thrombosis

We investigated the antithrombotic effect of anti-glycoprotein (GP) IIb/IIIa antibody in a primate model of lethal thrombosis. Eight monkeys were injected intravenously with an anti-CD9 antibody (MALL13). They died within 5 min and displayed severe thrombocytopenia. Histological examination showed multiple platelet thrombi in the pulmonary microvasculature, but no thrombi in the liver, kidneys, or spleen. In contrast, monkeys pretreated with an anti-GPIIb/IIIa antibody (NNKY1-32) at 30 min before MALL13 administration did not die, and the thrombocytopenia in these animals did not develop as rapidly or become as severe. These results suggest that the antiCD9 antibody caused lethal pulmonary thrombosis in vivo, and that pretreatment with the anti-GPIIb/IIIa antibody was able to prevent this thrombosis.

Topical phenytoin in wound healing

BACKGROUND

Phenytoin, introduced in 1937 as an antiseizure medication, has since been reported to promote wound healing when applied as a topical agent. This study was undertaken to evaluate its effectiveness in chronic skin ulcers.

METHODS

Seventy-five inpatients with chronic skin ulcers were included in this controlled trial. Forty patients were treated with topical phenytoin, and 35 patients with conventional saline dressings. Assessment of the wounds included wound area, bacteriologic cultures, and clinical assessment by blind observers at baseline and every 7 days thereafter over the 4-week treatment period.

RESULTS

Wound area reduction was greater in the phenytoin group than in controls. Fifty percent of phenytoin-treated wounds had negative cultures by day 7, compared to 17% of controls. Healthy granulation tissue appeared earlier with phenytoin. At the end of the fourth week, 29 of 40 phenytoin-treated ulcers had healed completely versus 10 of 35 controls.

CONCLUSIONS

Topical phenytoin appears to be an effective, inexpensive, and widely available therapeutic agent in wound healing. Further clinical use and evaluation is merited.

Hydrolysis of micellar diheptanoylphosphatidylcholine catalyzed by bovine pancreatic phospholipase A2: kinetic characterization of group I and II enzymes

Initial velocity data for the hydrolysis of micellar 1,2-diheptanoyl-sn-glycero-3-phosphorylcholine (diC7PC) catalyzed by bovine pancreatic PLA2 (Group I) were analyzed using the Michaelis-Menten equation. The Km value for the micellar substrate was found to be independent of Ca2+ concentration, as was the Km value for the monodispersed substrate. The pH dependence curve of Km in the presence of saturating amounts of Ca2+ showed two transitions reflecting large pK shifts of two ionizable groups from 5.0 to 5.45 and from 9.5 to 10.25, whereas the Km value for the monodispersed substrate was independent of pH [Fujii et al. (1991) J. Biochem. 110, 1008-1015]. The pH dependence curve of kcat showed three transitions, indicating the participation of three ionizable groups with pK values of 5.45, 8.4, and 10.25. Deprotonation of the first group and protonation of the third group were found to be essential for catalysis. The respective groups were assigned as the catalytic group His 48, the N-terminal alpha-amino group, and invariant Tyr 52. The present results as well as those for another Group I PLA2 (Naja naja atra) are very different from those for Group II PLA2s (Agkistrodon halys blomhoffii and Trimeresurus flavoviridis), which showed Ca(2+)-dependent substrate binding and no participation of the alpha-amino group in catalysis [Teshima et al. (1989) J. Biochem. 106, 518-527; Nishimura et al. (1992) J. Biochem. 111, 210-218].(ABSTRACT TRUNCATED AT 250 WORDS)

[Study on the inhibitory effect of AA-2414 on platelet aggregation and its clinical effect in asthmatic patients]

We previously reported that AA-2414, an eicosanoid receptor antagonist, inhibits platelet aggregation mediated by TXA2/PGH2 receptors in patients with bronchial asthma, but that the inhibitory effects differ among individuals. In this study, we measured the in vitro inhibition rate of platelet aggregation by AA-2414 using U-46619 as an aggregating agent in 22 asthmatic patients and classified them into Group A (showing an inhibition rate of 60% or more) and Group B (showing a rate of less than 60%). Subsequently, AA-2414 tablets (40 mg/day) were orally administered to both groups for 6 weeks, and the clinical effects were compared. A positive correlation was observed between the in vitro U-46619-induced platelet aggregation rate and the inhibition rate of aggregation by AA-2414. At the end of administration, marked inhibition of U-46619-induced platelet aggregation was observed in all patients. However, Group A showed a higher improvement rate of symptoms than Group B. Asthmatic patients can be classified into the groups showing good or poor platelet responses. The response may reflect reactivity to TXA2 in the local airway.

[Clinical study on the inhibitory effect of AA-2414 on platelet function in asthmatic patients]

We studied the effect of AA-2414, a TXA2 receptor antagonist, on platelet function in 12 asthmatic patients, 6 males and 6 females, whose mean age was 43.6 years. AA-2414 was orally administered to each patient at 20 mg/day for two weeks and then at 40 mg/day for the following two weeks. Platelet aggregation, plasma concentration of TXB2, and serum concentrations of AA-2414 and its metabolites were measured before and after the administration of each dose. Platelet aggregation induced by U-46619 (an analogue of PGH2), STA2 (a stable analogue of TXA2) and arachidonic acid with the administration of AA-2414 was significantly inhibited. The degree of this inhibition was proportional to the serum level of the drug. Plasma concentration of TXA2 tended to be lowered by administration of AA-2414, but it was not statistically significant. Eight (75.0%) of the 12 patients showed clinical improvement. In the cases where the drug was ineffective, the inhibition of platelet aggregation after administration of AA-2414 was less than in those cases where it was effective. We conclude that AA-2414 might exert its antiplatelet and antiasthmatic effects through antagonism of the TXA2 receptor. Investigation of the response to AA-2414 may be useful in assessing the clinical effect of this compound.

Spin-state equilibrium in the model complexes of azide hemoprotein

Addition of NaN3 to ferric protohemin biscoordinated with 1-methylimidazole (1-MeIm) or 2-methylimidazole (2-MeIm) in (CH3)2SO resulted in sizeable visible absorption changes, corresponding to the formation of the mixed ligand complexes, hemin X N-3 X 1-MeIm and hemin X N-3 X 2-MeIm. The visible absorption spectrum of the 1-MeIm complex was closely similar to those of azide hemoproteins, while the 2-MeIm derivative exhibited intensified 500 and 625 nm bands and depressed 540 and 570 nm peaks. The iron-bound N-3 of the model complexes exhibited two infrared stretching bands, which were assigned to the high- and low-spin peaks. The intensity of the high-spin infrared peaks increased at higher temperature. From the analyses of the infrared spectral changes, the thermodynamic values of the thermal spin equilibria were determined to be delta H = -3920 cal/mol and delta S = -11.1 e.u. for hemin X N-3 X 1-MeIm and delta H = -2150 cal/mol and delta S = 7.9 e.u. for hemin X N-3 X 2-MeIm. The thermodynamic values of the 1-MeIm complex are similar to the reported values for azide metmyoglobin, suggesting that the contribution from the nonbonded porphyrin-globin contacts to the spin equilibrium is small in azide metmyoglobin. Comparison of the delta H and delta S values among model systems indicates that delta H and delta S compensation similar to that observed in hemoprotein also holds in the models. This may suggest an underlying common denominator for the spin-equilibrium mechanisms in hemins and hemoproteins.

Mercury exanthem

We experienced 15 patients with generalized rash, mostly appearing a day or two after breaking a clinical thermometer or during dental treatment. Similar skin manifestations were revealed, suggestive at first glance of mercury exanthem, i.e. diffuse symmetrical erythema predominantly on major fluxural areas. An inverted triangular or V-shaped erythema on both upper antero-medial thighs was a common feature. Severe cases had miliary pustules and/or purpura on erythematous skin. Pruritus or burning sensation was relatively mild. Pyrexia or malaise was a complaint of more than half the patients. Most of the patients had a previous history of contact dermatitis to Mercurochrome, and by patch-testing were found to have contact allergy to several mercurials, especially inorganic ones. Until recently, Mercurochrome had been most widely used as a topical disinfectant in Japan. This seems to be a possible cause of the high incidence of contact allergy to mercurials in this country. From our findings we feel that our patients had developed systemic contact dermatitis due to inhalation of mercury vapor.

Quaternary structure and spin-state transition in azide methemoglobin A

The temperature-dependent ultraviolet and visible absorption changes of human azide methemoglobin with and without inositol hexaphosphate (IHP) were examined in a 4'-35 degrees C range. The 537-nm absorption change of IHP-free hemoglobin was about 1.2-fold larger than that of IHP-bound hemoglobin. The data were analyzed by considering the thermal spin equilibrium within the R and T conformers and the quaternary equilibrium between the two conformers. The spin equilibrium analysis suggested that the T conformer has a larger high-spin content than the R conformer. The quaternary equilibrium analysis, on the other hand, showed that the T conformer is more populated at lower temperature. The thermodynamic values for the quaternary equilibrium were determined to be delta H = -13.3 kcal/mol and delta S = -47.6 eu. The large negative delta H and delta S values were compensated for each other to give a small energy difference between the two quaternary states, e.g., delta G4 = 670 cal/mol of tetramer at 20 degrees C. The coincidence of the temperature-dependent IHP-induced changes in the visible and ultraviolet absorptions of heme and aromatic chromophores at the subunit boundaries suggested that the quaternary transition energy is not localized at heme moiety. The reverse temperature dependence of the T conformer fraction as compared with the high-spin fraction of heme iron was interpreted as indicating that the appearance of the T state is not directly coupled with an increase in the strain of Fe-N(F8 His) linkage in azide methemoglobin A.

Quantitative structure--activity relationship of double alkyl chain drugs

The quantitative structure--activity relationship of double alkyl chain drugs, including alkanols, aliphatic esters, ketones, barbiturates, amphetamines, butyrylcholinesterase inhibitors, antimalarials, and rifamycin amides, is investigated. A series of double-chain homologues, CnH2n+1XCmH2m+1, in which n changes, keeping m constant, is classified into three types: in type IIL, n greater than m; in type IIE, n = m; in type IIS, n less than m. When a linear relationship, vis., log (1/C) = an + b, holds, the slope a depends on the type; aI greater than or equal to aIIL greater than aIIE greater than aIIS. Here aI means the slope for single-chain homologues. The same order is observed for the equation, log hydrophobicity = an + b, where the hydrophobicity of drug denotes the water solubility, the critical micelle concentration, and the partition coefficient for the 1-octanol--water phases. Therefore, decreased biological activity of a double-chain drug relative to that of a single-chain isomer can be explained by a decreased hydrophobicity of the double-chain drug, due to the intramolecular association of these chains in water. When a parabolic relationship between log (1/C) and n holds, the optimum n depends on the type: nopI less than nopIIL less than nopIIE. This order is also explicable on the basis of a decreased hydrophobicity of double-chain drug. The N-dealklation rate of amphetamines in vivo appears to be affected by the steric factor as well as the hydrophobic factor. A decreased hydrophobicity of double-chain compounds should be taken into consideration for estimating their partition coefficients.