Norma I. Cruz

Comparative evaluation of aloe vera in the management of burn wounds in guinea pigs.

An experimental study was designed using Hartley guinea pigs, who received full-thickness burns covering 3 percent of their body surface area by direct contact with a hot plate. A total of 40 animals were equally divided among four modalities of closed burn wound management as follows: group I: silver sulfadiazine (Silvadine); group II: aloe vera gel extract (Carrington Dermal Wound Gel); group III: salicylic acid cream (aspirin); and group IV: plain gauze occlusive dressing only. The dressings were changed daily, and the size and appearance of each burn wound were recorded until complete healing. On the sixth postburn day, quantitative burn wound cultures were made. The average time to complete healing in the control group was 50 days, and the only significant difference was found in the aloe vera-treated animals, which healed on an average of 30 days (p less than 0.02). Wound bacterial counts were effectively decreased by silver sulfadiazine (p = 0.015) and by aloe vera extract (p = 0.015). From our data it appears that aloe gel extracts permit a faster healing of burn wounds.

Evaluation of Fibrin Glue in Rat Sciatic Nerve Repairs

Using the rat sciatic nerve model, we evaluated the merits of homologous fibrin glue in the repair of peripheral nerve transections as compared to standard epineural suture repairs. A total of four study groups were used, with 10 animals assigned to each group. In group I, the transected sciatic nerve was repaired with six interrupted 10–0 nylon sutures; in group II, only two interrupted sutures were used; in group III, a two-suture repair was reinforced with fibrin glue; and in group IV, only fibrin glue was used. All animals were sacrificed at 8 weeks, and histologie sections evaluated. When fibrin alone was used, dehiscence occurred in 80 percent of the animals, and as reinforcement of a two-suture repair, it only increased the inflammatory reaction.

Lactational performance after breast reduction with different pedicles.

Background: Uncertainty still exists as to whether one type of pedicle is superior to another in preserving the breastfeeding potential of young women who need breast reduction surgery. Methods: The lactational performance of women who had breast reduction surgery with different pedicle types was compared with that of women of child-bearing age with macromastia but no prior breast surgery. Of those who had reduction mammaplasty, 48 had superior, 59 had medial, and 57 had inferior full-thickness dermoglandular pedicles. A total of 151 women with macromastia but without prior breast surgery comprised the control group. All women completed a questionnaire on breastfeeding success. Successful breastfeeding was defined as breastfeeding for 2 weeks or more. The women were also classified as having breastfed exclusively or with supplementation. Results: Of the women in the control group who attempted to breastfeed, 62 percent were successful. Breastfeeding success rates for patients who had breast reduction surgery were 62 percent for superior pedicle, 65 percent for medial pedicle, and 64 percent for inferior pedicle. No significant difference (p > 0.05) was found between groups. Thirty-four percent of the control group supplemented breastfeeding and no significant difference was found between the control group and the patients who had breast reduction surgery with superior (38 percent), medial (38 percent), and inferior (35 percent) pedicles. Loss of nipple sensation was 2 percent for all pedicle types. Conclusion: The lactational performance of women who had breast reduction surgery using superior, medial, or inferior full-thickness pedicles was not significantly different from that of women with macromastia but no breast surgery.

Breastfeeding after augmentation mammaplasty with saline implants.

It has been reported that breastfeeding problems occur in women who have breast implants.The breastfeeding success of women who had augmentation with saline implants and subsequently had a live birth (n = 107) was compared with that of women of similar age who had hypoplastic breasts and had children before their consultation (n = 105). A self-administered 11-item questionnaire was used to collect data on demographics and breastfeeding success. The information requested included age, weight, height, whether breastfeeding was attempted, if it was successful, and the need to supplement. Additional information requested from the study group included position of breast scar, implant volume, and whether loss of nipple sensation had occurred after the surgery (as judged by the patient).The groups were not significantly different in age (22 ± 7 vs. 23 ± 5). There was, however, a significant difference (P < 0.05) in the breastfeeding success and need to supplement feedings. Successful breastfeeding occurred in 88% of the control and 63% of the study group. A need to supplement breastfeeding occurred in 27% of the control group but increased to 46% in the study group. No significant difference (P > 0.05) was found in the breastfeeding experience between periareolar and inframammary approaches. Loss of nipple sensation after augmentation mammaplasty was reported by 2% of both the periareolar and inframammary subgroups.The success rate of breastfeeding decreases ∼25% and the need to supplement breastfeeding increases 19% in young women with hypoplastic breasts after augmentation mammaplasty, irrespective of whether a periareolar or inframammary approach is used.

The Effect of Systemic Isotretinoin on Wound Contraction in Guinea Pigs

An experimental study was designed using Hartley guinea pigs to evaluate wound contraction on animals receiving systemic isotretinoin at a dose of 10 mg/kg. Half the animals received isotretinoin for 4 weeks before the surgery and for 2 weeks after the surgical procedure. A square of skin and panniculus carnosus measuring 200 mm2 was excised from the back of each animal, and the amount of wound contraction was determined by a computer program from the drawings on celluloid overlays done weekly. The animals on systemic isotretinoin had a significant delay in wound contraction when compared to control animals (p < 0.001). When the medication was discontinued, all the animals had complete wound healing within a week.

Management of contaminated bone grafts.

Using an experimental animal model, the infection rate of contaminated bone grafts after irrigation with either normal saline, povidone-iodine, or a cefazolin solution was evaluated. Mechanical cleansing appears to be the important factor in preventing infection in these grafts, since all the solutions showed almost equal effectiveness. As the amount of bulk and dead space increases, particularly in Pseudomonas infections, povidone-iodine might be slightly superior, although this difference was not statistically significant.

Cholecystectomy and right colon cancer in Puerto Rico

A case‐control study was undertaken to evaluate the possible relationship between cholecystectomy and right colon cancer. Two hundred patients with adenocarcinoma of the cecum or ascending colon (diagnosed between 1984 and 1989) were compared with 200 matched neighborhood controls. Cholecystectomy history was obtained through interviews using structured questionnaires and subsequently validated from hospital records. A statistically significant association (odds ratio = 2.14) was found between right colon cancer and a history of prior cholecystectomy. the altered bile metabolism which occurs after removal of the gallbladder may have a carcinogenic effect on the right colon. Dietary habits of the colon cancer patients in our study were consistent with prior reports in the literature, showing that this group has a lower intake of vegetables and cereal fiber than the control population.

Muscle flaps in the management of vascular grafts in contaminated wounds: an experimental study in dogs.

This study evaluates in an animal model the efficacy of muscle flaps in protecting the fabric vascular prosthesis when placed in contaminated wounds. A total of 20 adult mongrel dogs received a 2-cm interpositional polytetrafluoroethylene (PTFE) graft to each femoral artery at the groin level. During the surgical procedure, the wounds were inoculated with a Staphylococcus aureus suspension containing either 1 × 104 or 1 × 105 organisms per milliliter. In half the animals, the grafts were wrapped with a distally based sartorius muscle flap before a standard two-layer closure was completed. One month after the surgery, all the animals were sacrificed and quantitative cultures were performed of the grafts and wounds. The muscle flaps were capable of protecting the vascular prosthesis with inoculums up to 1 × 104 organisms (p < 0.05), but at greater bacterial contamination their efficacy was no longer significant.

The effect of a high fat diet on the incidence of colonic cancer after cholecystectomy in mice

An experimental study was designed to evaluate the effects of both a high fat diet and a cholecystectomy on the incidence of carcinogen‐induced colon cancer in mice. Sixty pink‐eyed jax (P/J) mice were divided equally into two groups. One group was fed a standard rodent diet and the other group received a diet supplemented with 20% corn oil. From each diet group, 50% of the mice had a cholecystectomy and the other 50% had a sham operation. Two weeks after surgery, each mouse received weekly subcutaneous injections of a carcinogen (dimethylhydrazine, 20 mg/kg) for 12 weeks. After the treatment period, the mice were killed and their large bowels were examined. Evaluation of the results demonstrated that the mice that had a cholecystectomy and a high fat diet had the highest incidence (P < 0.05) of colonic adenocarcinomas.

An experimental model to determine the level of antibiotics in irradiated tissues

An experimental study was designed using male Sprague-Dawley rats treated with a single dose of 1800 rads to an area of skin and soft tissue of the back measuring 2 X 3 cm. This dose was estimated to produce changes equivalent to 6000 rads in divided doses over 6 weeks. At intervals of 5, 10, and 15 weeks after irradiation, punch biopsies were taken from both irradiation, and nonirradiated skin areas of each animal 30 minutes after the intraperitoneal administration of gentamicin. Skin homogenates were prepared, and the antibiotic levels in these samples were determined by a bacterial growth inhibition assay. The antibiotic levels were found to be equal (16.1 +/- 6 micrograms/ml vs. 16.0 +/- 5 micrograms/ml) in both irradiated and nonirradiated skin at 5 weeks after radiation. However, at 10 and 15 weeks after radiation, the antibiotic levels had dropped to 9.9 +/- 3 micrograms/ml in irradiated skin compared with 14.1 +/- 4 micrograms/ml in normal skin (p less than 0.001) and with 5.4 micrograms/ml in irradiated skin vs. 11.8 +/- 5 micrograms/ml in nonirradiated skin (p less than 0.001), respectively. Results demonstrate that in spite of adequate gentamicin levels in the circulation and nonirradiated tissue in rats, gentamicin has a decreasing ability to diffuse into irradiated tissues with increasing intervals after therapeutic doses of radiation.