Antibacterial effects of Carica papaya fruit on common wound organisms

The purpose of the study was to investigate antibacterial activity of ripe and unripe Carica papaya on selected micro-organisms. Cultures of micro-organisms were routinely maintained in nutrient agar slants at 4 degrees C. Extracts of immature, mature and ripe Carica papaya fruit were obtained by separately grinding factions of the epicarp, endocarp and seeds and filtering them through gauze. Sensitivity tests were conducted by adding 0.06 ml of extract to agar wells (6 mm diameter) prepared from 20 ml agar seeded with 10(6) cells/ml suspension of one of the eight organisms per plate. The inoculated plates were allowed to equilibrate at 4 degrees C for 1 hour, incubated at 37 degrees C for 24 hours, and zones of inhibition measured in millimetres. Anti-bacterial activity was expressed in terms of the radius of zone of inhibition. Seed extracts from the fruit showed inhibition in the following order: B cereus > E coli > S faecalis > S aureus > P vulgaris > S flexneri. No significant difference was found in bacterial sensitivity between immature, mature and ripe fruits. No inhibition zone was produced by epicarp and endocarp extracts. Carica papaya seeds contain anti-bacterial activity that inhibits growth of gram-positive and gram-negative organisms. Observed activity was independent of stage of fruit maturity. Carica papaya has antibacterial effects that could be useful in treating chronic skin ulcers to promote healing

Antibacterial effects of Carica papaya fruit on common wound organisms.

The purpose of the study was to investigate antibacterial activity of ripe and unripe Carica papaya on selected micro-organisms. Cultures of micro-organisms were routinely maintained in nutrient agar slants at 4 degrees C. Extracts of immature, mature and ripe Carica papaya fruit were obtained by separately grinding factions of the epicarp, endocarp and seeds and filtering them through gauze. Sensitivity tests were conducted by adding 0.06 ml of extract to agar wells (6 mm diameter) prepared from 20 ml agar seeded with 10(6) cells/ml suspension of one of the eight organisms per plate. The inoculated plates were allowed to equilibrate at 4 degrees C for 1 hour, incubated at 37 degrees C for 24 hours, and zones of inhibition measured in millimetres. Anti-bacterial activity was expressed in terms of the radius of zone of inhibition. Seed extracts from the fruit showed inhibition in the following order: B cereus > E coli > S faecalis > S aureus > P vulgaris > S flexneri. No significant difference was found in bacterial sensitivity between immature, mature and ripe fruits. No inhibition zone was produced by epicarp and endocarp extracts. Carica papaya seeds contain anti-bacterial activity that inhibits growth of gram-positive and gram-negative organisms. Observed activity was independent of stage of fruit maturity. Carica papaya has antibacterial effects that could be useful in treating chronic skin ulcers to promote healing.

Progressive nonulcerative paracentral keratolysis associated with elevated corneal metalloproteinases.

PURPOSE: We report a patient with progressive idiopathic, nonulcerative, noninflammatory, avascular, bilateral, paracentral and peripheral corneal thinning monitored for 13 years. METHODS: Because of progressive corneal thinning, the patient underwent several surgical procedures, including an arcuate lamellar keratectomy with suturing, bilateral 15-mm diameter onlay lamellar corneoscleral epikeratoplasties, and removal of interface epithelial tissue. Over time, the keratolysis also thinned the donor stroma, requiring a lamellar tectonic graft. A biopsy was performed of the patient's cornea and conjunctiva, and the tissue was analyzed for proteolytic enzymes. RESULTS: Increased quantities of matrix metalloproteinases (57 and 63 kDa) were extracted from the patient's normal-appearing and abnormal corneal samples but not from adjacent conjuctiva and sclera or normal controls. This is the first reported case with these clinical and laboratory findings. CONCLUSION: A previously undescribed progressive idiopathic paracentral keratolysis is associated with increased quantities of matrix metalloproteinases. Clinical management requires tectonic corneal surgery.

Synthetic epikeratoplasty in rhesus monkeys with human type IV collagen.

Human type IV collagen discs were found to support proliferation and adhesion of rabbit corneal epithelial cells in tissue culture. To assess the biocompatibility of this synthetic collagen for epikeratoplasty, seven eyes of seven rhesus monkeys underwent epikeratoplasty with lenticules made of human type IV collagen. Eye rubbing by the animals expulsed two of the lenticules and caused failure of two to epithelialize completely. The remaining three lenticules epithelialized, remained clear, and caused no adverse effects on the eye. Two of these lenticules developed focal areas of subepithelial thinning 3 months postoperatively and the third lenticule has remained stable for 30 months. The presence of epithelial attachment components at the epithelial-lenticule interface was demonstrated by immunolocalization. Histopathologic and ultrastructural examination revealed focal areas of epithelial invasion and degradation of the lenticule. Neutral proteases were detected in the thinning region of one specimen. Human type IV collagen supports epithelialization in vivo and may have potential as a biomaterial for epikeratoplasty, but the stability of the material must be improved.

Changes in the nuclear structure in the radiation-sensitive CHO mutant cell, xrs-5.

The structural organization of the cell nucleus was investigated by transmission electron microscopy in the radiosensitive Chinese hamster ovary (CHO) cell mutant, xrs-5 (D0 = 45 cGy), relative to parental K1 cells (D0 = 200 cGy). In 99% of all xrs-5 cells, the outer layer of the nuclear envelope was separated from the inner layer, while 96% of K1 cells had closely apposed layers. This separation of the inner and outer layers of the nuclear envelope in xrs-5 cells was not explained by an increased susceptibility of xrs-5 cells to osmotically induced changes because (1) xrs-5 cells retained the altered nuclear periphery even when several different fixation protocols were used and (2) xrs-5 cells were not more susceptible to cell lysis as measured by trypan blue dye exclusion or by the extracellular presence of lactate dehydrogenase. The difference in the morphological organization in the nuclear periphery of xrs-5 cells correlated with the radiation sensitivity of the cells; xrs-5 cells which spontaneously reverted to a radiation sensitivity similar to that of K1 cells also reverted to a nuclear morphology similar to that of K1 cells. The inner and outer layers of the nuclear envelope were retained in nuclear scaffolds isolated from K1 and xrs-5 cells, indicating that components of the nuclear periphery are part of the nuclear scaffold. These data show that xrs-5 cells have an altered nuclear periphery which correlates with the radiation sensitivity of the cells. The separation of the layers of the nuclear envelope may represent an altered template for repair of DNA damage at the nuclear scaffold and thus may play a role in the defective repair of X-ray-induced DNA double-strand breaks in xrs-5 cells.

Current status of synthetic epikeratoplasty.

Many of the deficiencies with human tissue epikeratoplasty might be improved by the use of a suitable synthetic lenticule. Potential biomaterials for epikeratoplasty include collagen (types I, III, or IV), collagen-hydrogel copolymers, bioactive synthetics, and coated hydrogels. The biomaterial must be engineered to achieve strict specifications of optical clarity, support of epithelial migration and adhesion, permeability to solutes, and stability to corneal proteases. Attaching synthetic lenticules to the cornea without cutting Bowman's layer by adhesives, laser welding, or direct adhesion may also improve the efficacy of synthetic epikeratoplasty.

Collagenase secretion accompanying changes in cell shape occurs only in the presence of a biologically active cytokine.

We have investigated the relationship between collagenase production, cell shape and stimulatory factors in cell culture. In a homogeneous culture of primary rabbit corneal stromal cells, shape change induced by a variety of agents was not effective in stimulating collagenase secretion. Only in the presence of a biologically active cytokine or phorbol myristate acetate was a correlation seen between changes in cell shape (induced by a second agent) and collagenase secretion by these primary cells. Cell shape changes were not, however, necessary for collagenase secretion, since certain concentrations of endotoxin or lactalbumin hydrolysate effected secretion of the enzyme in the absence of morphological changes. With passaged cells or mixed cell cultures, where cell shape change did correlate with collagenase secretion without the addition of an exogenous agent, the production of an effective cytokine (autocrine or paracrine) was demonstrated. Thus cell shape change seems to be neither universally necessary nor sufficient for the stimulation of collagenase secretion. It is proposed that the function of cytokines may be more immediately related to gene expression in this system than is change in the shape of the cell. The hypothesis is presented that cell shape changes may render the target cells receptive to cytokines, perhaps by replacing the need for a natural cytokine cofactor. It is also demonstrated here that the use of passaged cells, mixed cell cultures containing endogenous cytokine-secreting cells or tissue culture additives can profoundly affect the interpretation of the effect of various agents on collagenase secretion, and may lead to observations that are not directly relevant to cell function in vivo.

A community-based study of gastrointestinal helminth and protozoan infection in Western Jamaica

A study of gastrointestinal parasitic infection was conducted in four communities in the Parish of Westmoreland, Jamica. All blood smears (n=1,025) werw negative and 63,7% of stool specimens (n=696) contained ova/cysts of one or more of 7 helminth and 9 protozoan spcecies. Trichuris and Giardia were the most prevalent species. Prevalence was markedly age-dependent, with infection occuring most commonly in children. It is concluded that gastreointestinal parasitic infections persist at intensity and prevalence levels likely to have a significant impact on community health

Regenerate epithelium and skin glands of the adult newt react to the same monoclonal antibody.

A search for specific proteins involved in newt limb regeneration, using monoclonal antibodies against forelimb blastemas, led to the detection of an antigen in the regenerate epithelium. Fluorescent-antibody-labeled cells first appeared just prior to blastema outgrowth. From bud through early digit stages this antibody reacted with nearly all of the regenerate epithelial cells. Other tissues also reacted, including nerve, blood vessels, and gastrointestinal tract. The behavior of the reactive cells in the regenerate epithelium, and their close association with immediately adjacent skin glands, raises several new possibilities for the origin of the regenerate epithelium.

Stimulation of collagenase synthesis by a 20,000-dalton epithelial cytokine. Evidence for pretranslational regulation.

Certain products of cultured rabbit corneal epithelium or epidermis regulate collagenase production by rabbit corneal stromal cells. Here, we examined the effects of a 20-kDa cytokine derived from cultured epithelium on collagenase expression by normal human skin fibroblasts and by cells from recessive dystrophic epidermolysis bullosa, a disease characterized by over-production of a structurally altered collagenase. Culturing cells for 24 h in the presence of the cytokine resulted in an approximately 2-fold increase in trypsin-activatable collagenase activity paralleled by an increase in immunoreactive protein, suggesting enhanced synthesis. There was no change in the activity/immunoreactive protein, indicating a catalytically unaltered enzyme. In kinetic studies, stimulation of collagenase synthesis was first observed approximately 8 h after exposure to the epidermal cytokine. Conversely, when cells were primed with cytokine for 24 h and the stimulator was then removed, an increased rate of synthesis was seen for an additional approximately 9 h, after which the rate reverted to control levels. Since the kinetic data suggested an effect at a pretranslational level, fibroblasts cultured with 20-kDa stimulator were used to prepare mRNA. In cell-free translation total protein synthesis was unaltered; however, the cytokine caused a greater than 2-fold increase in translatable collagenase mRNA. The data suggest that this epithelial cytokine specifically modulates collagenase synthesis through transcription and that epithelial-stromal interactions are important to cutaneous connective tissue metabolism.

Organization of collagen types I and V in the embryonic chicken cornea: monoclonal antibody studies.

To determine whether type V collagen is antigenically masked in situ by its fibrillar organization, two different methods were used to perturb selectively the structure of collagen fibrils in sections of embryonic chicken corneas. The experimentally modified tissues were probed by immunohistochemical procedures with monoclonal antibodies against types V and I. A lathyritic agent was used to block crosslinking of newly synthesized collagen. This results in reversible temperature-sensitive alterations in fibrillar packing, such that freshly formed collagen fibrils retain their aggregated state at 37 degrees C but become dissociated upon cooling. Type V-specific immunofluorescence remained masked at 37 degrees C but was revealed at 0 degree C. The effect of temperature was partially reversible, indicating that type V collagen is normally unavailable for antibody binding because of its fibrillar arrangement. In sections of normal corneas, treatment with corneal collagenase, which degrades type I collagen, but not type V, also unmasked the latter. This implicates type I collagen as the masking agent. We propose that collagen types I and V are incorporated together in heterotypic fibrils.

Regulation of connective tissue collagenase production: stimulators from adult and fetal epidermal cells.

We have examined the ability of primary adult rabbit skin cells to regulate collagenase production in vitro. Dermal cells constitutively produce collagenase in culture, and enzyme production by these cells can be influenced by epithelial cells. Co-culture with skin epidermal cells resulted in more enzyme production by dermal cells, whereas co-culture with corneal epithelial cells yielded less enzyme activity. Connective tissue cells from a different source, cornea, also produced collagenase when co-cultured with skin epidermal cells, although the stromal cells alone made no enzyme. The drug cytochalasin B had very little influence on collagenase production by dermal cells, either alone or in co-culture with epidermal cells, but did significantly potentiate enzyme production by corneal stromal cells responding to epidermal effector molecules. Epidermal-cell-conditioned medium from both fetal and adult rabbit skin was a potent source of stimulators (apparent mol wt 20,500 and 55,000) of connective-tissue-cell collagenase production. Stimulator production by epidermal cultures was cell density dependent. Optimal production of stimulators occurred in adult cultures containing 10(6) epidermal cells/ml of medium, and in fetal cultures containing 10(5) cells/ml. Inhibitors of connective tissue cell enzyme production were not detected in conditioned medium from either adult or fetal epidermal cells.