Inhibitory effect of thymoquinone from Nigella sativa against SARS-CoV-2 main protease. An in-silico study

Abstract Nigella sativa is known for the safety profile, containing a wealth of useful antiviral compounds. The main protease (Mpro, 3CLpro) of severe acute respiratory syndrome 2 (SARS-CoV-2) is being considered as one of the most attractive viral target, processing the polyproteins during viral pathogenesis and replication. In the current investigation we analyzed the potency of active component, thymoquinone (TQ) of Nigella sativa against SARS-CoV-2 Mpro. The structures of TQ and Mpro was retrieved from PubChem (CID10281) and Protein Data Bank (PDB ID 6MO3) respectively. The Mpro and TQ were docked and the complex was subjected to molecular dynamic (MD) simulations for a period 50ns. Protein folding effect was analyzed using radius of gyration (Rg) while stability and flexibility was measured, using root means square deviations (RMSD) and root means square fluctuation (RMSF) respectively. The simulation results shows that TQ is exhibiting good binding activity against SARS-CoV-2 Mpro, interacting many residues, present in the active site (His41, Cys145) and also the Glu166, facilitating the pocket shape. Further, experimental approaches are needed to validate the role of TQ against virus infection. The TQ is interfering with pocket maintaining residues as well as active site of virus Mpro which may be used as a potential inhibitor against SARS-CoV-2 for better management of COVID-19.

Organoleptic characteristics and compositional profile of meat of growing Japanese quail fed different levels of poultry byproducts compost

The poultry industry generates a lot of waste, including dead birds, manure, and poultry litter. Poultry waste should never be disposed of improperly because it can seriously harm the environment. The waste can be recycled as a feedstock for use in poultry feed by composting the litter and deceased birds. The compositional profile and organoleptic properties of the meat of growing Japanese quail were examined over the course of a 4-week trial to ascertain the effect of adding compost to the diet. In a completely randomized design (CRD), 1200 newly hatched quail chicks (Coturnix coturnix japonica) were divided into five treatment groups (diets with 0, 2.5, 5, 7.5, and 10% compost), each consisting of 40 birds with six replicates. The addition of compost to the diet had no noticeable effects on the organoleptic qualities of appearance, color, aroma, taste, texture, juiciness, tenderness, and acceptability (P>0.05). The compositional profile characteristics for chicks given compost at any level compared to chicks fed the control diet showed no differences (P>0.05). These findings suggest that the sensory characteristics and compositional profile of growing meat quails can be maintained when fed diets including up to 10% compost.

Assessing effect of feeding poultry byproducts compost on organoleptic characteristics and compositional profile of meat of broiler chickens

Large amounts of waste, including dead birds, manure, and poultry litter, are produced by the poultry industry. Poultry waste should be disposed of properly to avoid major pollution and health risks. Composting litter and dead birds could be an option to recycle the waste and use in poultry feed. A study was conducted to investigate the effects of feeding composted poultry waste on the organoleptic qualities and compositional profile of the meat of broiler chickens. A total of 300 day-old broiler chicks (500-Cobb) were randomly allocated to five treatment groups replicated six times with 10 birds each, under a completely randomized design (CRD). Five iso-caloric and iso-nitrogenous diets including composted poultry byproducts at concentrations of 0, 2.5, 5, 7.5, and 10% were fed ad libitum to the birds from day 0 to day 35. The sensory grading and meat composition profile of 500 Cobb broiler chickens were tested at 35 days of age. The findings showed that there were no variations in the sensory profiles of the meat from birds given various diets (P>0.05). Although the results were somewhat lower for the chicks fed compost-containing diets than for the control group, this difference was deemed to be insignificant (P>0.05). Similarly, there were no variations in the compositional profile values of the meat between meat from birds fed various diets (P>0.05). These findings imply that broiler chickens may be raised on diets containing up to 10% poultry byproduct compost without any negative impacts on the meat's sensory quality or composition. Additionally, using compost into broiler diets may help to lower the cost of feed.

Assessing growth performance, morphometric traits, meat chemical composition and cholesterol content in four phenotypes of naked neck chicken

The present study was conducted to assess the growth performance, morphometric traits, muscle chemical composition and cholesterol content in four phenotypes of naked neck chicken (black, white-black, light brown and dark brown). A total of 320-day-old chicks, 80 from each phenotype, were randomly stratified into 20 replicates (16/replicate), according to a completely randomized design. The results showed higher final body weight, weight gain, and better FCR in both light brown and dark brown phenotypes whereas time of gains was found to be greater in dark brown phenotype. Keel length and shank circumference were greater in dark brown whereas wing spread was found to be higher in light brown phenotype. Drumstick circumference and body length did not show any significant differences (P > 0.05) across the phenotypes. Dry matter was found to be higher in white black, crude protein in black, white black and dark brown, moisture in light brown, and cholesterol content in black whereas ether extract and ash content were found to be greater in black and white black phenotypes. In conclusion, both light brown and dark brown phenotypes showed superior growth performance and morphometric traits. Similarly, from a health point of view, the dark brown and light brown phenotypes seem superior because their cholesterol content was low. Thus, it is strongly recommended that there should be a conscious effort to improve economically important traits of the light and dark brown birds to be used as dual-purpose slow growing chicken, especially in developing countries.

Stoichioproteomics study of differentially expressed proteins and pathways in head and neck cancer

Hypoxia is a prominent feature of head and neck cancer. However, the oxygen element characteristics of proteins and how they adapt to hypoxia microenvironments of head and neck cancer are still unknown. Human genome sequences and proteins expressed data of head and neck cancer were retrieved from pathology atlas of Human Protein Atlas project. Then compared the oxygen and carbon element contents between proteomes of head and neck cancer and normal oral mucosa-squamous epithelial cells, genome locations, pathways, and functional dissection associated with head and neck cancer were also studied. A total of 902 differentially expressed proteins were observed where the average oxygen content is higher than that of the lowly expressed proteins in head and neck cancer proteins. Further, the average oxygen content of the up regulated proteins was 2.54% higher than other. None of their coding genes were distributed on the Y chromosome. The up regulated proteins were enriched in endocytosis, apoptosis and regulation of actin cytoskeleton. The increased oxygen contents of the highly expressed and the up regulated proteins might be caused by frequent activity of cytoskeleton and adapted to the rapid growth and fast division of the head and neck cancer cells. The oxygen usage bias and key proteins may help us to understand the mechanisms behind head and neck cancer in targeted therapy, which lays a foundation for the application of stoichioproteomics in targeted therapy and provides promise for potential treatments for head and neck cancer.

Comparative analysis of various sources of selenium on the growth performance and antioxidant status in broilers under heat stress

The supplementation of Selenium-enriched probiotics is effective in reducing oxidative stress and maintaining meat quality stability in broiler chicken especially under heat stress. An experimental study was conducted to perform Comparative analysis of Selenium yeast with inorganic Se in broilers under heat stress. A total of 120 broilers chicks of one day were assigned to 4 groups each consisting 30 chicks fed on same basal diet but different selenium sources. The basal diet of group D1 was not supplemented with Se source (Negative control), group D2 basal diet was supplemented with inorganic selenium (Sodium selenite 0.22mg/Kg starter phase and 0.15mg/Kg finisher phase), group D3 basal diet was supplemented with commercially available organic selenium (Seleno-methionine 0.22mg/Kg starter phase and 0.15mg/Kg finisher phase) and group D4 basal diet was supplemented with self-developed organic selenium (Se-enriched yeast 0.22mg/Kg starter phase and 0.15mg/Kg finisher phase). The performance parameters i.e. feed intake (FI), live body weight (BW) and FCR were not significantly (p>0.05) effected by selenium supplementation in the starter phase but were significantly (p<0.05) effected in the finisher phase. Selenium supplementation significantly (p<0.05) effected serum Se level in different supplemented groups. Higher serum Se value (58.20±0.06) was recorded in D4 group. Similarly significantly lower selenium value was recorded for D4 and higher was recorded for D1 (11.36±0.08). However lower serum Paraoxonase (PON) value was recorded for D4 (13.24±0.01) and higher for D1 (13.33±0.03). Comparatively self-developed Se enriched yeast increased the Se accumulation and improved antioxidant system. Glutathione peroxidase (GPx) was found higher in D4 (12.333±0.03) followed by D3, D2 and D1 respectively. Whereas superoxide dismutase (SOD) was significantly lower (p<0.05) in D4 (0.1437±0.003) followed by D3 (0.1457±0.002). Selenium supplementation increased the bird's survival rate. Birds fed on Se enriched yeast showed higher Se deposition and better antioxidant capacity as compared to other sources of selenium. Se-enriched yeast displayed an improved result on Se deposition in tissues, and oxidative capacity, meat tenderness and immune response level as compared to other sources of selenium.

A threefold approach including quantum chemical, molecular docking and molecular dynamic studies to explore the natural compounds from Centaurea jacea as the potential inhibitors for COVID-19

In the current report, we studied the possible inhibitors of COVID-19 from bioactive constituents of Centaurea jacea using a threefold approach consisting of quantum chemical, molecular docking and molecular dynamic techniques. Centaurea jacea is a perennial herb often used in folk medicines of dermatological complaints and fever. Moreover, anticancer, antioxidant, antibacterial and antiviral properties of its bioactive compounds are also reported. The Mpro (Main proteases) was docked with different compounds of Centaurea jacea through molecular docking. All the studied compounds including apigenin, axillarin, Centaureidin, Cirsiliol, Eupatorin and Isokaempferide, show suitable binding affinities to the binding site of SARS-CoV-2 main protease with their binding energies -6.7 kcal/mol, -7.4 kcal/mol, -7.0 kcal/mol, -5.8 kcal/mol, -6.2 kcal/mol and -6.8 kcal/mol, respectively. Among all studied compounds, axillarin was found to have maximum inhibitor efficiency followed by Centaureidin, Isokaempferide, Apigenin, Eupatorin and Cirsiliol. Our results suggested that axillarin binds with the most crucial catalytic residues CYS145 and HIS41 of the Mpro, moreover axillarin shows 5 hydrogen bond interactions and 5 hydrophobic interactions with various residues of Mpro. Furthermore, the molecular dynamic calculations over 60 ns (6×106 femtosecond) time scale also shown significant insights into the binding effects of axillarin with Mpro of SARS-CoV-2 by imitating protein like aqueous environment. From molecular dynamic calculations, the RMSD and RMSF computations indicate the stability and dynamics of the best docked complex in aqueous environment. The ADME properties and toxicity prediction analysis of axillarin also recommended it as safe drug candidate. Further, in vivo and in vitro investigations are essential to ensure the anti SARS-CoV-2 activity of all bioactive compounds particularly axillarin to encourage preventive use of Centaurea jacea against COVID-19 infections.

Creating new guidelines on how best to treat foot symptoms in people with EB

Epidermolysis bullosa (EB) is a complex rare condition that affects the skin and many parts of the body. Those born with EB have skin so fragile they are called 'butterfly children', their skin is quite simply as fragile as the wing of a butterfly. In the UK it is estimated that there are more than 5,000 people living with EB and 500,000 worldwide. Little clinical guidance for care existed until DEBRA International started a programme to develop clinical practice guidelines (CPGs). There were no previous guidelines and few published studies on foot care in EB so treatment decisions were largely based on individual opinion and experience. The panel - made up of clinical experts and people living with EB representing Australia, the UK, and the USA - aimed to describe foot problems in people of all ages with EB, and summarise current evidence and management. The authors used a logical podiatric (foot) care literature review focussed on patients with EB. The authors found that the evidence in this area was limited but several interventions (treatments) currently practised by podiatrists show positive outcomes. The study allowed the group to make recommendations on how to treat foot and nail disorders in patients with EB. Furthermore, the authors concluded that further research is needed. This is a summary of the study: Foot care in epidermolysis bullosa: evidence-based guideline.

Foot care in epidermolysis bullosa: evidence-based guideline

This guideline was designed to provide service providers and users with an evidence-based set of current best practice guidelines for people and their families and carers, living with epidermolysis bullosa (EB). A systematic literature review relating to the podiatric care of patients with EB was undertaken. Search terms were used, for which the most recent articles relating to podiatric treatment were identified from as early as 1979 to the present day, across seven electronic search engines: MEDLINE, Wiley Online Library, Google Scholar, Athens, ResearchGate, Net and PubFacts.com. The Scottish Intercollegiate Guidelines Network (SIGN) methodology was used. The first guideline draft was analysed and discussed by clinical experts, methodologists and patients and their representatives at four panel meetings. The resulting document went through an external review process by a panel of experts, other healthcare professionals, patient representatives and lay reviewers. The final document will be piloted in three different centres in the U.K. and Australia. Following an EB community international survey the outcomes indicated six main areas that the community indicated as a priority to foot management. These include blistering and wound management, exploring the most suitable footwear and hosiery for EB, management of dystrophic nails, hyperkeratosis (callus), maintaining mobility and fusion of toes (pseudosyndactyly). The evidence here is limited but several interventions currently practised by podiatrists show positive outcomes.

Organic and inorganic selenium in Aseel chicken diets: Effect on hatching traits

A study was conducted to evaluate the effect of dietary selenium (Se) sources (organic and inorganic Se at 0.30 ppm and basal diet at 0 ppm level of supplemented Se) on hatching traits in four varieties of Aseel chicken, Lakha, Mushki, Peshawari, and Mianwali. In total, 84 adult molted hens (50 wk old), 21 from each variety, were randomly assigned to 12 treatment groups in a 3 (Se diets) × 4 (Aseel varieties) factorial arrangement under a randomized complete block design. Each treatment was replicated 7 times with individual hens in each. Settable egg, fertility, hatch of fertile eggs, hatchability, A-grade chick, and embryonic mortality parameters were evaluated. The results indicated that the birds fed an organic Se supplemented diet had greater (P < 0.05) settable eggs, fertility, hatch of fertile eggs, hatchability, and A-grade chicks and reduced embryonic mortality than those fed inorganic or no Se. Among varieties, Mushki had lower (P < 0.05) fertility, hatch of fertile eggs, hatchability, and A-grade chicks than rest of three varieties. Interaction of Se sources and varieties indicated that dietary organic Se supplementation improved (P < 0.05) hatch of fertile eggs in Peshawari and Mianwali, whereas hatchability only in Peshawari variety and reduced embryonic mortality in Mianwali. It was concluded that dietary supplementation of organic Se could be used to improve hatching traits as well as reduce embryonic mortality in native Aseel chicken.

Pyrazinamide-resistant mycobacterium tuberculosis isolates from Khyber Pakhtunkhwa and rpsA mutations

Pyrazinamide (PZA) is a key first-line antibiotic used for the short-course treatment of drug-sensitive and multidrug-resistant (MDR) isolates of tuberculosis. PZA exhibits potent action against semi-dormant bacilli in acidic environments. However, mutations that occur in target genes may cause technical difficulties in the diagnosis of PZA resistance during drug susceptibility testing. The objective of the current study is to identify mutations in pncAWT rpsA and rpsAWT panD genes among PZA-resistant isolates of Mycobacterium tuberculosis (MTB) circulating in the Pashtun dominant region, Khyber Pakhtunkhwa, Pakistan. We selected 18 PZA-resistant pncAWT strains from the Provincial Tuberculosis Reference Laboratory (PTRL) Khyber Pakhtunkhwa to investigate mutations in the coding region of rpsA and panD genes. The experiments were repeated for drug susceptibility testing using MGIT 960 automated system. In addition, eighteen PZA-resistant rpsA genes along with 5 susceptible strains and one H37Rv strain were sequenced. All 18 isolates were PZA-resistant. The majority of these isolates exhibited multidrug resistance (MDR) (13/18). We identified 14 non-synonymous and one synonymous mutation in the coding region of rpsA in 11 strains. All mutations were scattered throughout the gene and not reported previously. Further, we did not identify any mutation in 7 rpsAWT panD genes. Mutations in rpsA but not in panD occur in PZA-resistant pncAWT MTB isolates circulating in Khyber Pakhtunkhwa, Pakistan.

Assessing behavior in Aseel pullets under free-range, part-time free-range, and cage system during growing phase

The objective of this study was to explore the effects of free-range (FR), part-time free-range (PTFR), and cage system (CS) on behavioral repertoire in Lakha (LK), Mushki (MS), Peshawari (PW), and Sindhi (SN) varieties of Aseel chicken during the growing phase (9 to 18 wk of age). In total, 144 Aseel pullets were allotted to 12 treatment groups in a 3 × 4 (rearing system × Aseel variety) factorial arrangement, according to a randomized complete block design (RCBD). Each treatment group was replicated 3 times with 4 birds in each replicate (12 birds per treatment group). The pullets were randomly marked weekly for identification, and their behavior was observed through the focal animal sampling method. Time spent on different behavioral activities was recorded and converted to a percentage. The data were analyzed using 2-way ANOVA under a factorial arrangement using SAS 9.1, and the behavioral parameters were evaluated. The results indicated greater (P < 0.05) sitting, standing, drinking, preening, and aggressiveness in CS; walking, running, and jumping in PTFR; and foraging and dustbathing in both FR and PTFR, whereas feather pecking was found to be reduced in FR compared with PTFR and CS. Among varieties, PW showed the least feeding/foraging and feather pecking behavior, and greater standing, running, and jumping behavior (P < 0.05). However, SN spent less time in walking and preening, and more time in sitting, drinking, and aggressiveness. Dustbathing was found to be similar in all Aseel varieties (P = 0.135). In conclusion, the PTFR system could be suggested as a substitute for conventional housing systems because it better accommodates normal behavior in Aseel pullets.

Blood biochemistry and immune response in Aseel chicken under free range, semi-intensive, and confinement rearing systems

A study was conducted to investigate the effects of 3 different rearing systems [free range ( FR: ), semi-intensive ( SI: ), and confinement ( CF: )] on blood biochemical profile and immune response in 4 varieties of Aseel chicken [Lakha ( LK: ), Mushki ( MS: ), Peshawari ( PW: ) and Sindhi ( SN: )] for 10 wk duration (7 to 16 wk). At the age of 6 wk, in total, 180 cockerels were assigned to 12 treatment groups, 3 (rearing system) × 4 (Aseel chicken variety) factorial arrangement in 7 randomized complete blocks, replicated 3 times with 5 birds in each replicate (45 birds of each variety; 60 birds in each rearing system; 36 total replicates). Blood samples were collected through brachial vein at the end of wk 16. After laboratory analysis, the recorded data for blood biochemical profile and immune response were analyzed by using 2-way ANOVA under factorial arrangement. The results showed higher (P < 0.05) plasma glucose and total protein in birds under CF. Titer against Newcastle disease virus ( NDV: ) and infectious bronchitis virus ( IBV: ) was found to be greater (P < 0.05) in SI and FR, respectively. Peshawari birds indicated higher (P < 0.05) concentration of glucose, total protein, albumin, uric acid, creatinine, and titers to NDV and IBV. Birds of LK and SN varieties also indicated maximum antibody titer against NDV and IBV, respectively. Cholesterol level was found to be greater (P < 0.05) in birds of LK and SN. Interaction of SN with FR revealed maximum (P < 0.05) cholesterol whereas interaction of PW with SI indicated maximum antibody titer against NDV. The results highlight that CF rearing system expediently affects glucose and total protein levels in birds; SI and FR confer maximum antibody titers to NDV and IBV. Birds of PW variety indicated higher glucose, total protein, albumin, uric acid, and creatinine, the lowest cholesterol under FR and the enhanced antibody titer against NDV and IBV.

Management of the giant-cell tumours of the distal radius

BACKGROUND

Giant-cell tumour of the distal radius is a rare neoplasm that affects the peri-articular metaphysial region of the bone. Curettage alone or with bone grafting has been reported to be associated with high incidence of local recurrence in these tumours. In the present series, we report the results of curettage only as the treatment for primary giant-cell tumour of the distal radius carried out at a single centre.

PATIENTS AND RESULTS

A total of 287 patients with giant-cell tumour have been referred to us for treatment over the last 28 years; 24 of these were found to have lesion in the distal radius. One patient underwent endoprosthetic replacement of the distal radius. The remaining 23 patients underwent curettage of the primary neoplasm. Four out of the 23 (17%) patients developed local recurrence of disease, The mean time to local recurrence was 17 months (range, 9-27 months). Complications such as collapse of the articular cartilage are more common in patients with an extensive soft tissue component of the tumour.

CONCLUSIONS

Curettage alone is adequate treatment for the majority of patients with giant-cell tumours of the distal radius but some form of stabilisation may be required in the presence of extensive bone destruction.

Subperiosteal schwannomas of the femur

We report a case of two adjacent femoral subperiosteal schwannomas in a 38-year-old man. To our knowledge, this is the first report of a schwannoma arising as a surface lesion of bone. Radiographs showed focal cortical scalloping and MR imaging two small hyperintense nodules on T2-weighted and STIR images which enhanced with a gadolinium chelate.

A comparative study of effects of cigarette and bidi smoking on respiratory function tests

The effects of cigarette and bidi smoking on pulmonary function tests have been studied in 90 healthy males from North India Forced vital capacity (FVC), peak expiratory flow rate (PEFR), forced expiratory volume in 1 sec (FEV) were determined in 30 nonsmokers (as control group), 30 cigarette smokers and 30 bidi smokers. All the above pulmonary function parameters were found to be lower among smokers as compared to nonsmokers. Moreover, the decrease in the pulmonary function tests was greater in cigarette smokers as compared to bidi smokers.

Comparison of aztreonam against other antibiotics used in urinary tract infections

BACKGROUND

Urinary tract infection is a very common problem in adults as well as in children. There is always need for the right antibiotic to be chosen for treatment.

METHODS

This study was conducted at Microbiology section in Pathology department of Ayub Medical College, Abbottabad, Pakistan. In this study the aztronam which is only effective against gram negative bacilli has been compared with other conventionally used antibiotics, ampicillin, cotrimoxazole, minocyclin, pipemedic acid, nalidixic acid, norfloxacin, ciprofloxacin, gentamicin and ceftriaxon.

RESULTS

Total gram negative isolates were 342. Out of this 76.6% (262) were E. coli, klebsiella pneumoniae 14.3% (49), proteus species 5.2%(18) and pseudomonas aeruginosa were 3.8% (13). The aztreonam showed 78% sensitivity against gram negative bacilli which is better than norfloxacin which showed 62.2% sensitivity.

The effects of aqueous extracts of Desmodium gangeticum DC. (Leguminosae) on the central nervous system

The aqueous extract of Desmodium gangeticum DC. (Leguminosae) showed no analgesic activity in the hot plate method, but it showed severe anti-writhing activity in the acetic acid-induced abdominal writhing assay. It exhibited moderate central nervous system depressant activity in the spontaneous motor activity, hole cross, and open field tests and hole board tests. The effects of this extract on locomotion were compared with some standard CNS drugs.

Characterization of Membrane-Associated Proteasomes in WB Rat Liver Epithelial Cells

Although proteasomes are mainly located in the cytosol, it is known that significant amounts are also associated with endoplasmic reticulum (ER) membranes where they may play a role in the degradation of specific ER membrane proteins. The present studies were undertaken to compare ER and cytosolic proteasomal activities in WB rat liver cells. N-Heptyl-beta-thioglucopyranoside (HTG) extracts of membrane or cytosol fractions were chromatographed in glycerol/ATP buffers on size-exclusion and ion-exchange columns and the elution profiles of proteasomal peptidase activity and immunoreactive components of the 20S complex, 19S complex, and PA28 were compared. Cytosol fractions showed a single peak of chymotrypsin-like peptidase activity (Cht-L), which was inhibited completely by 5 microM lactacystin (LC) or SDS (0.03%) and corresponded to 26S proteasomes based upon the presence of both 20S and 19S components. By comparison, membrane fractions contained two major peaks of Cht-L activity. The first peak shared the same properties as the peak activity observed in cytosol fractions. However, the second peak was stimulated by SDS and was LC-insensitive (5 microM) and contained trypsin-like (T-L) and peptide-glutamyl peptidase (PGPH) but no cathepsin or calcium-activated protease activities. PA28 activator protein was present in both membrane and cytosol fractions. Thus, the principal difference between cytosolic and membrane activity was that the latter fractions contained a novel membrane-associated LC-insensitive protease(s) catalyzing three of the major peptidase activities of the proteasome.

High tibial osteotomy without internal fixation for medial unicompartmental osteoarthrosis

Between 1982 and 1993, a total of 35 patients underwent high tibial osteotomy for medial unicompartmental osteoarthrosis. The osteotomy was performed high in the tibia without the use of jigs, and internal fixation devices were avoided. Patients were assessed using the British Association for Surgery of the Knee score, and satisfactory results with minimal complications were obtained. Our results indicate that in a select group of patients, high tibial osteotomy preserves bone stock and is performed near the deformity so that excellent correction is achieved and recurrence of varus deformity is avoided.

Structure and function of procollagen C-proteinase (mTolloid) domains determined by protease digestion, circular dichroism, binding to procollagen type I, and computer modeling

Procollagen C-proteinase-2 (pCP-2, mTld) is derived from the longest splicing variant of the gene encoding bone morphogenetic protein 1 (BMP-1). The variants have identical amino terminal signal peptides, prodomains and astacin-like protease domains. However, they differ in the length of their carboxy terminal part, which in pCP-2 has the composition CUB1, CUB2, EGF-like1, CUB3, EGF-like2, CUB4, CUB5, and C-tail. In the shorter form, pCP-1 (i.e., BMP-1), the sequence ends after the CUB3-domain. Using a combination of mutagenesis and structural approaches, we have investigated the structure and function of subfragments of pCP-2. The full-length latent recombinant enzyme and its N-terminally truncated form lacking the prodomain were tested for their enzymic activity. The intact protein showed only partial processing of procollagen type I, whereas the truncated form expressed enzymic activity indistinguishable from its native counterpart purified from chick embryo tendons. These results clearly demonstrated that the prodomain is required for the latency of the enzyme but not for its correct folding. Limited proteolysis of the recombinant protein with alpha-chymotrypsin produced four discrete fragments revealing the location of cleavage sites between the repetitive CUB/EGF domains. The results provide evidence that the CUB sequences form independently folded modules that are stabilized by two pairs of internal disulfide bridges. The modules are linked to each other by more flexible, hinge-like peptides. Solid-phase binding assays with isolated CUB domains and immobilized procollagen type I demonstrated that the first three but not the last two CUB domains specifically bound to the substrate. To define putative sites for CUB-CUB or CUB-substrate interactions, we generated molecular models for pCP-2 CUB domains. The models were obtained using as a template the structure of CUB domain in zona pellucida adhesion protein PSP-I/PSP-II from porcine sperm. The predicted conformations for homology models were, subsequently, confirmed by circular dichroism spectroscopy of polypeptide domains isolated following limited proteolysis with alpha-chymotrypsin.

Allograft bone transplantation: a Sheffield experience

There has been an increase in demand for allograft bone in recent years. This type of bone provides an excellent material to fill in bony defects, but could be associated with an incidence of infection. Any newly established tissue bank has to meet the very stringent criteria to process and store bone and maintain a donor and recipient database to avoid transmission of infection. The Sheffield Tissue Bank has been functioning since 1989 and until 1993 has provided bone allografts to 220 patients; these have been used mainly to reconstruct defects at revision hip and knee arthroplasty and for scoliosis surgery. There have been no cases of disease transmission and the rate of infection has been reduced by strict screening protocols. This paper outlines our experience, problems and success with human bone banking.

Identification and characterization of a calmodulin-binding domain in Ral-A, a Ras-related GTP-binding protein purified from human erythrocyte membrane

A 28-kDa protein (p28) has been purified from Triton X-100 extracts of human erythrocyte plasma membrane by calmodulin affinity chromatography. Based on internal peptide sequencing and its protein amino acid composition, this protein has been shown to be highly related, if not identical to, Ral-A, a Ras-related GTP-binding protein. This protein assignment is consistent with the findings that p28 binds [32P]GTP specifically and has low GTPase activity. In this study we describe the identification and characterization of a calmodulin-binding domain in Ral-A. The Ca2+-dependent interaction of p28 with calmodulin was first detected by a calmodulin affinity column. Gel overlay experiments of both p28 and recombinant Ral-A with biotinylated calmodulin provided strong evidence that Ral-A is a calmodulin-binding protein. A peptide of 18 residues (P18) with the sequence SKEKNGKKKRKSLAKRIR has been identified as a putative calmodulin-binding domain in Ral-A, because it comprises a basic/hydrophobic composition with the propensity to form an amphiphilic helix. P18 was synthesized, and its interaction with calmodulin by gel overlay was shown to be Ca2+-dependent. Circular dichroism analysis demonstrated that this interaction results in less alpha-helical content upon calmodulin complex formation. These results indicate that Ral-A is a calmodulin-binding protein, raising the possibility that it may be associated with Ca2+-dependent intracellular signaling pathways.

The podiatric treatment of hallux abducto valgus and its associated condition, bunion, with Tagetes patula

To assess the effectiveness of marigold therapy using Tagetes patula preparations, a double-blind placebo-controlled trial was designed to be carried out over a period of eight weeks. Sixty patients were entered in the trial. Twenty patients with bilateral hallux abducto valgus and its associated condition, bunion, were randomly selected from 37 subjects for group A. For group B, 40 patients with unilateral hallux abducto valgus and bunion were randomly selected from 69 subjects and subdivided into groups Ba and Bb. Patients with ulcerated conditions, those on medication and those who had undergone surgery for the condition were excluded. The results obtained were highly significant (P < 0.001), suggesting that T. patula preparations, plus protective pad, were effective in reducing the width of the lesion and level of pain of hallux abducto valgus.

Studies on the differential morphological alterations in human and goat erythrocytes against ATP depletion and Ca(2+)-induced stresses

Erythrocyte membranes obtained from goat exhibited Ca2+/calmodulin-insensitive (Ca(2+)-Mg2+)-ATPase activity and the activity levels were significantly lower as compared to those obtained from human erythrocyte membranes. Although Ca2+/ionophore A23187 -treatment enhanced the intracellular Ca2+ levels in both the freshly collected human and goat erythrocytes, negligible loss of ATP was noticed in goat erythrocytes under such conditions. Also, fluoride, a known metabolic inhibitor, caused a lesser ATP depletion in goat erythrocytes compared to that of human. Goat erythrocytes showed remarkable rigidity to shape change and unlike human erythrocytes, did not undergo echinocytic formation as a result of metabolic depletion and Ca2+/ionophore A23187-treatments. These studies suggest the participation of (Ca(2+)-Mg2+)-ATPase -independent mechanism(s) for Ca(2+)-extrusion.

Identification and purification of a 90-kDa membrane-bound endogenous inhibitor of multicatalytic proteinase from human erythrocytes

We have identified and purified an endogenous inhibitor of multicatalytic proteinase (MCP) from human erythrocyte membranes. The inhibitor showed a molecular mass of 90 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The inhibitor protein was purified from the erythrocyte membranes using Heparinagarose and hydroxylapatite chromatography and the size exclusion on a Biogel A 1.5 m column in the presence of high salt. The 90-kDa protein inhibited all three peptidase activities of MCP; trypsin-like, chymotrypsin-like and peptidyl glutamyl peptide hydrolyzing (PGPH). However, it failed to cause any significant inhibition of caseinolytic activity of MCP, suggesting that the regulation of proteinase and peptidase activities is distinct. The inhibition of the chymotrypsin-like activity was noncompetitive. The results suggest that the 90-kDa inhibitor protein may be an important regulator of membrane-bound MCP.

Unlike its human counterpart, band 3 anion exchange protein from goat erythrocyte membrane shows a lack of reactivity against various -SH oxidants and protease treatments

Studies involving a number of -SH oxidants and proteases were made to analyse the organization of band 3 in goat erythrocyte membrane. -SH oxidizing agents such as diamide, Cu2+.o-phenanthroline and phenylene dimaleimide, known to cause cross-linking of human erythrocyte band 3, failed to show any cross-linking in the case of goat band 3 protein. When resolved to their individual components using -SH reducing agent beta-mercaptoethanol, high molecular weight protein adducts formed as a result of diamide treatment did not show any band 3 on two-dimensional electrophoresis. Also no proteolysis of band 3 was detected when intact goat erythrocytes were exposed to pronase, though marked proteolysis was noticed in the case of human band 3 proteins under similar conditions. These studies involving -SH oxidant and protease treatments suggest a different organization for goat erythrocyte band 3 protein as compared to that of human in erythrocyte membrane.

Membrane-bound high molecular mass proteinases from human erythrocytes

Two high molecular mass proteinases, multicatalytic proteinase (MCP) and a new high molecular mass proteinase (HMP) with only chymotrypsin-like activity (Khan et al. (1994) J. Biol. Chem. 269, 10016-10021) from human erythrocyte membranes, have been compared. For this purpose, MCP was purified from human erythrocyte membranes in the active form towards synthetic peptide substrates; it also hydrolysed the protein substrates [14]methyl casein and [14C]oxidised insulin beta chain at 37 degrees C. MCP from plasma membranes exhibited hollow cylindrical structures also typical of cytosolic forms. Radiolabelled diisopropyl fluorophosphate, [3H]DFP, a serine proteinase inhibitor, labelled a band of Mr 23 000 in membrane MCP. By contrast, no labelling was obtained with HMP. Chymotrypsin-like activity of HMP was also found to be insensitive to DFP. On the other hand, DFP inhibited chymotrypsin-like and peptidylglutamyl peptide hydrolysing activities of membrane MCP, with no effect on its trypsin-like activity. The inhibition of MCP by DFP was concentration-dependent. These studies showed that MCP and HMP represent two distinct kinds of proteinases with chymotrypsin-like activities and can be distinguished by the serine proteinase inhibitor DFP.

Characterization of a novel high molecular mass protein with peptidase activity purified from the human erythrocyte membrane by calmodulin affinity chromatography

A previously undescribed high molecular mass protein (HMP) from human erythrocyte membranes was solubilized by Triton X-100 and purified on a calmodulin-agarose column in the presence of Ca2+. It was shown to have a native molecular mass of 522-560 kDa, comprised of a single subunit of a molecular mass of 28 kDa (p28). The protein is associated with the lipid bilayer rather than with the cytoskeletal component of the membrane. The purified HMP showed peptidase-hydrolyzing activity toward substrates containing hydrophobic amino acids at the P1 position of the P2-P1 cleavage site. The activity was inhibited by serine proteinase inhibitors (leupeptin, phenylmethansulfonyl fluoride) and chymotrypsin inhibitors in particular (chymostatin, N-tosyl-L-phenylalanine chloromethyl ketone). The enzyme exhibited maximal activity at slightly alkaline pH (7.5-8.5) and at 37 degrees C and was stimulated over a narrow range of SDS concentrations (maximal at 0.05%). HMP was found to cross-react in Western blots with an antibody raised against the rabbit multicatalytic proteinase. The single subunit of HMP therefore contains both the catalytic activity and a sequence necessary for its association into a multimeric complex. The properties of the human erythrocyte membrane HMP described indicate that it is a novel peptidase related to the ubiquitous multicatalytic proteinase.

Vasodilation induced by acetylcholine and by glyceryl trinitrate in rat aortic and mesenteric vasculature

In endothelium-containing rings of rat aorta which had been precontracted with phenylephrine, addition of acetylcholine (ACh) (0.010-10 microM) resulted in concentration-dependent, graded relaxation through the release of endothelium-derived relaxing factor (EDRF). Hemoglobin (3 and 10 microM) and methylene blue (10 microM) both produced marked inhibition of this EDRF-mediated relaxation. In the perfused mesenteric arterial vasculature of the rat, ACh-induced vasodilation was also inhibited by hemoglobin and by methylene blue, although to a lesser extent than was ACh-induced relaxation of aortic rings by these two agents. These findings indicate that EDRF mediates in large part ACh-induced relaxation of resistance vessels in the mesenteric vascular bed as well as large arteries. The nitrovasodilator glyceryl trinitrate (GTN) caused endothelium-independent relaxation of aortic rings as well as vasodilation of mesenteric arterial vasculature. GTN-induced relaxation of aortic rings was antagonized by hemoglobin as well as methylene blue, but to a lesser extent than was ACh-induced relaxation. However, hemoglobin did not inhibit and methylene blue actually potentiated GTN-induced vasodilation in the perfused mesenteric vasculature. Possible explanations of these paradoxical results are discussed.

Goat erythrocyte calmodulin is not abnormal

Calmodulin was purified from goat erythrocyte hemolysate using heat treatment and Sephadex G-100 gel filtration chromatography. The molecular weight and Stokes, radius of the purified calmodulin was determined. The goat erythrocyte calmodulin stimulated (Ca(2+)-Mg2+)-ATPase but not (Mg2+)-ATPase and (Na(+)-K(+)-Mg2+)-ATPase. The (Ca(2+)-Mg2+)-ATPase of the erythrocyte membrane derived from human, rat, rabbit and pig were significantly stimulated.

Serpentine aneurysm of the posterior circulation: report of two cases

Giant serpentine aneurysms form a subgroup of giant intracranial aneurysms with specific radiological and surgical features. Previous reports have stressed the predilection of these lesions for the carotid circulation, particularly the middle cerebral artery. Two cases of serpentine aneurysm affecting the posterior circulation are reported and the problems of diagnosis and treatment of this lesion are discussed.

Lack of some Ca2+-mediated processes in goat erythrocytes

Ca2+ does not promote crosslinking of proteins nor stimulate proteolysis in goat and sheep erythrocyte membranes. Neither crosslinking nor proteolysis was observed even when the goat erythrocytes were loaded with calcium with the help of calcium ionophore A23187. Membrane-free human erythrocyte hemolysate, however, induced Ca2+-dependent crosslinking in goat erythrocyte membranes.

Evidence for endothelium-dependent vasodilation of resistance vessels by acetylcholine

In the perfused mesenteric arterial vasculature of the rabbit, vasodilation by acetylcholine (ACh) was almost completely blocked after a 15-min perfusion of the vasculature with 0.2% collagenase, an enzyme capable of removing endothelial cells. In the perfused mesenteric arterial vasculature of the rat, vasodilation by ACh was markedly, though not completely, inhibited by hemoglobin (10 microM), an agent which can inactivate endothelium-derived relaxing factor (EDRF). These results suggest that a major component of vasodilation of mesenteric resistance vessels in rabbit and rat by ACh is mediated by EDRF.

Studies on the inhibitory effect of ouabain on the release of [3H]-noradrenaline from the rat heart

In the rat Langendorff heart perfused with Krebs solution and prelabeled with [3H]-noradrenaline, ouabain caused arrhythmia as well as significant inhibition of spontaneous and electrically stimulated release of tritium. However, there is no causal relationship between the inhibition of tritium release and the occurrence of arrhythmia. Chromatographic analysis of the labeled perfusate suggests that ouabain reduced intact [3H]-noradrenaline fraction obtained during electrical stimulation. The inhibitory effect of ouabain on electrically stimulated release was completely antagonized by atropine, but not by indomethacin and phenoxybenzamine. However, none of the above agents antagonized the inhibitory effect of ouabain on spontaneous tritium release. Infusion of acetylcholine also inhibited electrically stimulated tritium release, and this effect was largely abolished by atropine. Thus it appears that in high concentrations, ouabain may release acetylcholine, which in turn activates presynaptic muscarinic inhibitory receptors leading to inhibition of noradrenaline release from the rat heart.

Anti-hyperglycaemic effect of an extract of Myrtus communis in streptozotocin-induced diabetes in mice

Intraperitoneal injection of streptozotocin (150 mg/kg) in mice produced an initial transient hyperglycaemia at 2 h followed by a second hyperglycaemic phase after 48-72 h which persisted throughout the 7-day observation period. An ethanol-water extract of Myrtus communis (2 g/kg) administered intragastrically 30 min before streptozotocin abolished the initial hyperglycaemic without affecting the second phase. Myrtus extract given prior to streptozotocin and repeated at 24 h and 30 h, did not allow hyperglycaemia to develop until after 48 h. Administration of Myrtus extract 48 h after streptozotocin significantly reduced the hyperglycaemia and this effect was maintained by its repeated administration. Myrtus extract had no effect on the blood glucose level of normal mice. These studies confirm the "folk-medicine" indication of Myrtus extract as potentially useful in the treatment of diabetes mellitus.

Modulation by prostaglandins of the release of [3H] noradrenaline evoked by potassium and nerve stimulation in the isolated rat heart

In the isolated rat heart perfused with Krebs solution and prelabeled with [3H] noradrenaline, we examined the effect of prostaglandins (PG) I2, E2, 6-keto-PGF1 alpha and their precursor, arachidonic acid, on the overflow of tritium elicited by potassium (K+) and by stimulation of cardiac sympathetic nerve plexus. Prostaglandins E2, I2 and arachidonic acid but not 6-keto-PGF1 alpha reduced K+ and nerve stimulation-induced overflow of tritium. Administration of indomethacin, an inhibitor of cyclooxygenase, increased tritium overflow elicited by either K+ or by nerve stimulation. During infusion of indomethacin, the inhibitory effect of both PGE2 and PGI2 on the K+ or nerve stimulation-induced overflow of tritium remained unaltered. In contrast, the effect of arachidonic acid to reduce K+ or nerve stimulation-induced overflow of tritium was abolished by indomethacin, indicating that the fatty acid inhibits release of tritium by its conversion to a product(s) of cyclooxygenase, presumably PGI2 and PGE2. These data suggest that prostaglandins, particularly PGI2 and PGE2 synthesized in the isolated rat heart act on prejunctional sites to modulate release of the adrenergic transmitter.