Hydrogeological constraints on riparian buffers for reduction of diffuse pollution: examples from the Bear Creek watershed in Iowa, USA.

Riparian Management Systems (RiMS) have been proposed to minimize the impacts of agricultural production and improve water quality in Iowa in the Midwestern USA. As part of RiMS, multispecies riparian buffers have been shown to decrease nutrient, pesticide, and sediment concentrations in runoff from adjacent crop fields. However, their effect on nutrients and pesticides moving in groundwater beneath buffers has been discussed only in limited and idealized hydrogeologic settings. Studies in the Bear Creek watershed of central Iowa show the variability inherent in hydrogeologic systems at the watershed scale, some of which may be favorable or unfavorable to future implementation of buffers. Buffers may be optimized by choosing hydrogeologic systems where a shallow groundwater flow system channels water directly through the riparian buffer at velocities that allow for processes such as denitrification to occur.

Ethical principles and theories.

Ethical theory about what is right and good in human conduct lies behind the issues practitioners face and the codes they turn to for guidance; it also provides guidance for actions, practices, and policies. Principles of obligation, such as egoism, utilitarianism, and deontology, offer general answers to the question, "Which acts/practices are morally right?" A re-emerging alternative to using such principles to assess individual conduct is to center normative theory on personal virtues. For structuring society's institutions, principles of social justice offer alternative answers to the question, "How should social benefits and burdens be distributed?" But human concerns about right and good call for more than just theoretical responses. Some critics (eg, the postmodernists and the feminists) charge that normative ethical theorizing is a misguided enterprise. However, that charge should be taken as a caution and not as a refutation of normative ethical theorizing.

Anatomy of a vesicular-arbuscular endomycorrhizal symbiosis between sugar maple (Acer saccharum Marsh) and Glomus etunicatum Becker & Gerdemann.

Microscopic analysis of infection development by Glomus in sugar maple roots revealed changes in the cortical cells similar to those reported by other workers using either herbaceous or woody plant hosts. Few cortical cells contained exclusively terminate hyphal structures. Instead, large intracellular hyphae entered and exited cortical cells while arbuscules formed from initiation points at various places on the intracellular hyphae. Intercellular hyphae were rare and vesicles were not observed. The beaded root morphology observed did not seem to influence the infection process. Beaded roots are formed from repeated constrictions in feeder roots due to major reductions in cell size. The relationship between the constrictions and moisture stress is discussed. The living arbuscule seemed to be the site of transfer between the host and endophyte, implying that the process is an active one.

Cleft palate fistula repair. Improved results by the addition of bone.

A retrospective study of cleft palate repairs showed a 22% fistula incidence. Of these 49% were judged to be symptomatic. Of the fistulae, approximately half required treatment. Of the conventional type surgical closures, there was only a 35% success rate. Conventional methods of surgical repair of anterior hard palate fistulae were seen to result in the very poorest permanent closure. As a result of this study, a new protocol was developed which has resulted in marked improvement in the surgical repair of anterior fistulae. We now close these fistulae in early adolescence following completion of orthodontic expansion using gingival and palatal flaps after the addition of free periosteal grafts or cancellous bone grafts.

Cleft palate fistula repair. Improved results by the addition of bone.

The treatment of cleft palate fistulas is currently unstandardized, and the outcome is often unsuccessful. Conventional surgical techniques for the repair of such fistulas involving bony defects have essentially been abandoned by the author. Current protocol calls for their repair in early adolescence (before the age of 10 years) following completion of any required orthodontic expansion of the maxillary dental arch. At the time of fistula repair, all scar tissue is excised between the maxillary segments. Both palatal and gingival soft-tissue flaps are developed to cover either free cancellous bone grafts or free periosteal grafts used to bridge the maxillary defect. This change in technique has resulted in osteogenic filling of the maxillary bony defect and has markedly improved the success rate of fistula repair. Furthermore, it has enhanced the aesthetic correction of the nasal alar base cleft stigmas.

Immediate and long-term management of gunshot wounds to the lower face.

The steadily increasing level of urban violence and attempted suicides in the recent past has resulted in large numbers of gunshot injuries to the face from small-caliber weapons. Our experience with 35 consecutive cases of civilian gunshot wounds involving primarily the lower face is presented. Initial management included securing of the airway, control of bleeding, and treatment of coexisting injuries. After clinical and radiologic evaluation and conservative debridement of all devitalized tissues, the mandibular fractures were reduced and stabilized appropriately. Large bony defects were treated by stabilization of the mandibular segments followed by secondary bone grafting. Intraoral soft tissues were then repaired with local mucosal flaps or tongue flaps when necessary. Finally, the soft tissues were repaired by primary closure or local flaps. Distant flaps were used only as a secondary procedure. Our results are presented, the differences between civilian and military injuries are discussed, and the principles of gunshot ballistics are described. We conclude that most of these wounds can be treated in a relatively conservative manner immediately after the injury with good functional and cosmetic results.

Management and timing of cleft palate fistula repair.

This study reviewed 199 cleft palate repairs resulting in 22 percent fistula formation. Of these, 49 percent were judged to be symptomatic. Of 44 fistulas, 21 required treatment, of which 14 had conventional type surgical closure with an overall success rate of 35 percent. Good surgical technique and good surgical judgment were felt to be important factors both in preventing postoperative fistula and in the success of their repair. Conventional methods of surgical repair of hard palate fistulas were seen to result in a very poor success rate. Orthodontic movement of maxillary segments was seen to contribute to late postoperative fistula formation. Therefore, orthodontic movement should be completed before undertaking surgical repair of anterior palatal fistulas. Finally, the success rate of anterior fistula repair has been dramatically improved by the addition of free periosteal grafts and cancellous bone grafts.

Frontal sinus fracture following osteoplastic frontal sinus obliteration.

A patient who sustained frontal sinus fracture and who earlier had undergone an osteoplastic fat obliteration procedure is described. The literature is reviewed and recommendations are made for management of this and other cases of frontal sinus fractures with posterior table involvement.

The use of uniform simulated models in the reconstruction of craniopagus twins.

A unique approach to the planning of the separation and subsequent reconstruction of craniopagus twins is presented. In consultation with medical artists and prosthetists, exact models of our patients were fabricated preoperatively. Models were made of a hard acrylic to simulate bone and silicone rubber to simulate skin. In this fashion, the surgical teams were given an opportunity to preplan the bony separation of the heads, as well as to design the best possible coverage for reconstruction of the resulting defects. Physiological, mechanical, and aesthetic considerations are discussed. Two surgical delay procedures were performed without complication prior to neurosurgical separation. A broad segment of inextricably interconnected cerebellar tissue and a shared sagittal sinus could not be overcome at the time of final separation and proved to be fatal for both twins. Owing to the untimely deaths, we can only postulate that the delayed compound musculocutaneous flaps would have produced the best possible results and physiological protection for the extensive bony defects in both skulls resulting from this separation.

Further applications of Archimedes' principle in the correction of asymmetrical breasts.

Archimedes' law of buoyancy has been extended to the preoperative bedside assessment of volume differences between breasts, whatever their cause. The simple method described has proved to be a helpful aid in surgical procedures for the correction of breast asymmetry.

Mandibular reconstruction.

Although there is no general agreement, we think immediate reconstruction with free bone graft from the iliac crest or rib is the method of choice for a small mandibular body or arch defect without concomitant significant loss of soft tissue. Soft tissue reconstruction with well-vascularized tissue should always be performed when extensive loss of soft tissue occurs after hemimandibulectomy to avoid tension on the stump and mandibular drift. When postoperative radiation is not anticipated, immediate bone grafting is appropriate. A free bone covered by well-vascularized tissue or a composite graft is our primary choice, but alloplastic trays with cancellous bone can also be considered. If postoperative radiation is anticipated, only soft tissue repair should be performed and osseous reconstruction should be deferred until radiotherapy is completed. Defects of the arch require special attention because of the severe deviation of the mandibular stumps. Immediate reconstruction is recommended in uncomplicated cases, but secondary bone grafting will be needed when the patient is in poor condition, or postoperative radiation places the bone graft in jeopardy. In such cases, immediate stabilization of the bone segments by internal or external fixation is absolutely necessary. Finally, secondary reconstruction should be considered only if there is no evidence of residual tumor. The defect should be recreated, scarred or irradiated tissue resected, and immediate reconstruction obtained with well-vascularized pedicled or free flaps.

The acute effects of cigarette smoke exposure on experimental skin flaps.

Random vascular patterned caudally based McFarlane-type skin flaps were elevated in groups of Fischer 344 rats. Groups of rats were then acutely exposed on an intermittent basis to smoke generated from well-characterized research filter cigarettes. Previously developed smoke inhalation exposure protocols were employed using a Maddox-ORNL inhalation exposure system. Rats that continued smoke exposure following surgery showed a significantly greater mean percent area of flap necrosis compared with sham-exposed groups or control groups not exposed. The possible pathogenesis of this observation as well as considerations and correlations with chronic human smokers are discussed. Increased risks of flap necrosis by smoking in the perioperative period are suggested by this study.

The use of Clinitron therapy unit in the immediate postoperative care of pressure ulcers.

The conventional postoperative care of patients undergoing pressure ulcer operations is complicated and unsatisfactory. In an effort to improve this care, we used the Clinitron therapy unit, which provides a true flotation environment for the patient. The surface pressure on the skin constantly remains below the capillary closure pressure of 32 mm Hg, and therefore no change in the patient's position is required as with the other beds currently used. Its special design creates a bactericidal fluid medium in which the temperature can be controlled. Our experience with 16 patients using the Clinitron in the immediate postoperative period has been encouraging. Comments from the patients and the nursing and medical staff, as well as advantages and disadvantages of this modality are discussed.

Athletic facial injuries.

Most facial injuries that occur during athletic activities are of a minor nature, consisting of lacerations, contusions, and abrasions. These are usually treated by a team physician or an emergency department physician. However, minor injuries must be differentiated from the more significant injuries, especially those involving facial bone fractures. Significant facial trauma must be diagnosed accurately and treated with precision to avoid permanent facial deformity. Soft-tissue trauma as well as fractures are included in this review, and evaluation of the injured athlete is emphasized. A systematic approach is developed for diagnosing and treating common facial injuries in athletes.

Nerve staining with leucomethylene blue: an experimental study.

Identification and preservation of the facial nerve during extirpative and reconstructive surgery represents a challenge even for the experienced surgeon. We present an experimental intraoperative technique for staining the facial nerve and its branches that is safe, accurate, and inexpensive. Leucomethylene blue is injected into the precise region of the facial nerve. Staining of the surrounding tissues is efficiently reduced by irrigation with ascorbic acid solution, leaving only the facial nerve stained. This technique has been encouraging in rabbits, and with additional experience, we anticipate its use for intraoperative staining of the facial nerve in humans.