Search PubMed⌕ Search

Biomedical subjects

M Meuli

Publications and source records attributed to M Meuli.

At least 55 records · Page 3Linked to original sources
PubMed1995

Creation of myelomeningocele in utero: a model of functional damage from spinal cord exposure in fetal sheep.

A recent study in human fetuses with myelomeningocele (MMC) suggested that the primary malformation is not neural but a failed closure of the posterior vertebral column and paraspinal soft tissue, which leads to exposure and secondary destruction of the spinal cord. The goal of this study was to test whether chronic exposure of the normal spinal cord to the amniotic space produces a lesion similar to human MMC. In fetal sheep at 75 days' gestation (group A) and 60 days' gestation (group B) (term = 150 days), the lumbar spinal cord was exposed to the amniotic cavity by excising skin and paraspinal soft tissues, and by performing a laminectomy. Some animals from both groups were fetectomized and assessed morphologically at 100 days' gestation. The remainder were delivered near term and assessed clinically, electrophysiologically, and morphologically. In group A, all animals showed MMC-type pathology. The exposed spinal cord was herniated out of the spinal canal and rested on the dorsal membranes of a cystic sac. The neural tissue was stretched and flattened out. Histologically, the hallmarks of the spinal cord were not discernable and the cytoarchitecture was lost. These changes were less severe at 100 days than at term. The three survivors in group A were paraplegic. In group B, the two survivors and two fetuses harvested at 100 days had healed skin wounds and near normal spinal cord histology. The other animal harvested at 100 days had a MMC-type lesion with less severe histological changes. The two survivors had a mild paraparesis.(ABSTRACT TRUNCATED AT 250 WORDS)

Amnion↗
PubMed1995

A model of scarless human fetal wound repair is deficient in transforming growth factor beta.

Human fetal skin heals via scarless regeneration, whereas adult skin heals with scar. Scarless repair may reflect a distinct cytokine milieu. We studied the role of the cytokine transforming growth factor beta (TGF beta) using an established model of scarless human fetal skin repair in which human fetal skin is transplanted into a subcutaneous pocket on the flank of an adult nude mouse. In this model, wounded 16-week-gestation human fetal skin heals without scar, whereas wounded adult skin heals with scar. Seven days after transplantation, incisional wounds were made in the skin grafts. In the first phase of the study, wounds were harvested from 1 hour to 4 weeks postwounding, and immunohistochemistry was performed for TGF beta (isoform nonspecific), TGF beta 1, and TGF beta 2. Scarfree wounds in the fetal skin grafts did not show TGF beta staining. In contrast, wounds in adult grafts that heal with scar demonstrated isoform nonspecific TGF beta staining from 6 hours through 21 days, TGF beta 1 from 6 hours through 21 days, and TGF beta 2 from 12 hours through 7 days. In the second phase of the study, a slow-release disk with 0.01, 0.1, 1.0, or 10 micrograms of TGF beta 1 was placed beneath the fetal skin graft at the time of wounding. Fourteen days postwounding, there was marked scarring in the fetal grafts treated with TGF beta 1, and the size of the scar was proportional to the amount of TGF beta 1 applied.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

The 'PLUG' odyssey: adventures in experimental fetal tracheal occlusion.

In animal experiments, it has been shown that tracheal occlusion counteracts the pulmonary hypoplasia associated with congenital diaphragmatic hernia (CDH). Successful clinical implementation requires a reliable, reversible, and atraumatic technique of occluding the fetal trachea. With this clinical goal in mind, the authors evaluated the following three methods of tracheal occlusion in a fetal lamb CDH model: (1) an occluded foam-cuffed endotracheal tube, (2) a foam-cuffed endotracheal tube with a magnetically controlled flow valve, and (3) a tracheal insert constructed of a water-impermeable, expandable, polymeric foam, which is placed by a translaryngeal approach. The foam-cuffed endotracheal tube did not provide consistently reliable fetal tracheal occlusion. Although the magnetically triggered flow valve functioned well, it was not necessary to open the valve in utero (to prevent overdistension of the lungs), and the presence of the valve contributed to several occlusive failures. In contrast, the foam insert was easy to position and to remove from the trachea, while providing reliable tracheal occlusion for several weeks with consequent enlarged fetal lungs, increased lung fluid volumes, complete reduction of abdominal viscera, and improved pulmonary gas exchange after birth. Bronchoscopic evaluation of the foam-occluded neonatal tracheas showed little or no tracheal damage, which was confirmed during necropsy by gross and histological examination. Translaryngeal placement of a compressible, water-impermeable polymeric foam appears to be a simple and safe technique to achieve fetal tracheal occlusion.

Animals↗
PubMed1995

An adult-fetal skin interface heals without scar formation in sheep.

BACKGROUND: Fetal skin heals by regeneration rather than by adult-type scarring. Prior studies indicate that scarless healing is an intrinsic property of fetal tissue. METHODS: To answer the question of whether fetal tissue could influence the healing of adjacent adult tissue, adult sheepskin was transplanted on the backs of 60-days' gestation fetal lambs (term, 145 days). At time points 1, 3, 7, 14, 21, 28, 42, 56, and 63 days after transplantation, the grafts were harvested and the interfaces between adult and fetal skin were analyzed. RESULTS: The adult-fetal interface healed without scar formation. Control fetal sheep autograft (fetal-fetal) interfaces healed without scar, and adult sheep autograft (adult-adult) interfaces healed with scar. CONCLUSIONS: These results suggest that the juxtaposed fetal tissue prevented scar formation at the adult-fetal interface. We hypothesize that fetal cellular and matrix factors permit adjacent wounded adult tissue to heal without scar. These factors, once characterized, might be used clinically to induce scarless healing in children and adults.

Adult↗
PubMed1995

In utero surgery rescues neurological function at birth in sheep with spina bifida.

We hypothesize that the neurologic deficit associated with open spina bifida is not directly caused by the primary defect but rather is due to chronic mechanical and chemical trauma since the unprotected neural tissue is exposed to the intrauterine environment. We report here that exposure of the normal spinal cord to the amniotic cavity in midgestational sheep fetuses leads to a human-like open spina bifida with paraplegia at birth, indicating that the exposed neural tissue is progressively destroyed during pregnancy. When open spina bifida was repaired in utero at an intermediate stage, the animals had near-normal neurologic function. The spinal cord was deformed but largely preserved. These findings suggest that secondary neural tissue destruction during pregnancy is primarily responsible for the functional loss and that timely in utero repair of open spina bifida might rescue neurologic function.

Animals↗
PubMed1995

Exogenous transforming growth factor-beta amplifies its own expression and induces scar formation in a model of human fetal skin repair.

OBJECTIVE: Fetal skin wounds heal without scarring. To determine the role of TGF-beta 1 in fetal wound healing, mRNA expression of TGF-beta 1 was analyzed in human fetal and adult skin wounds. METHODS: Human fetal skin transplanted to a subcutaneous location on an adult athymic mouse that was subsequently wounded heals without scar, whereas human adult skin heals with scar formation in that location. In situ hybridization for TGF-beta 1 mRNA expression and species-specific immunohistochemistry for fibroblasts, macrophages, and neutrophils were performed in human adult wounds, fetal wounds, and fetal wounds treated with a TGF-beta 1 slow release disk. RESULTS: Transforming growth factor-beta 1 mRNA expression was induced by wounding adult skin. No TGF-beta 1 mRNA upregulation was detected in human fetal skin after wounding. However, when exogenous TGF-beta 1 was added to human fetal skin, induction of TGF-beta 1 mRNA expression in human fetal fibroblasts occurred, an adult-like inflammatory response was detected, and the skin healed with scar formation. CONCLUSIONS: Transforming growth factor-beta 1 is an important modulator in scar formation. Anti-TGF-beta 1 strategies may promote scarless healing in adult wounds.

Adult↗
PubMed1995

Fetal reconstructive surgery: experimental use of the latissimus dorsi flap to correct myelomeningocele in utero.

A recent study in human fetuses with myelomeningocele produced evidence that nonclosure of the spine leads to progressive damage of the exposed spinal cord during pregnancy. Thus in utero coverage might spare function. We tested the use of the latissimus dorsi flap for fetal myelomeningocele repair. In seven sheep fetuses, a lumbar myelomeningocele type of lesion was created at 75 days' gestation and was covered with a "reversed" latissimus dorsi flap at 100 days. At term, the three survivors had healed cutaneous wounds and normal hindlimb function. The vascular pedicle of the latissimus dorsi flap was patent, the viable flap covered the entire lesion, and the underlying spinal cord was grossly intact. We conclude that the latissimus dorsi flap repair is suitable for fetal surgery and provides efficient coverage of the lesion. These results have clinical implications, since fetal myelomeningocele repair may be a compelling way to reduce the severe neurologic deficit in humans.

Animals↗
PubMed1994

Lichen sclerosus et atrophicus causing phimosis in boys: a prospective study with 5-year followup after complete circumcision.

We prospectively investigated 100 pediatric patients suffering from phimosis and found a 10% incidence of lichen sclerosus et atrophicus. This condition usually can be diagnosed preoperatively because of its classic manifestation of severe phimosis due to a sclerotic, whitish ring at the tip of the prepuce, which in our cases was accompanied by sclerogenous glanular lesions. To our knowledge our study represents the first evidence that the development of secondary phimosis with no apparent reason in school-age boys is highly suggestive for lichen sclerosus et atrophicus. Complete circumcision is the therapy of choice because it completely removes all affected tissue and it allows spontaneous regression or resolution of glanular lesions. There has been no recurrence after 5 years of followup.

Adolescent↗
PubMed1994

Management of petrous bone fractures in children: analysis of 127 cases.

Petrous bone fractures (PBF) in children are relatively frequent. They are mostly diagnosed after collisions and falls. The complications typically associated with PBF were different types of hearing disorders in 69.1% of the patients who had audiometry, liquorrhea in 16.5%, palsy of cranial nerves in 10.8% (facial nerve palsy in 9.4%), bacterial meningitis, stenosis of the external ear canal, and posttraumatic cholesteatoma in 0.7% of the fractures each. Most complications were transient; 8.6% of the patients underwent surgery because of PBF-related complications and 9.4% suffered from severe, irreversible sequelae. Management of PBF in children requires an interdisciplinary approach between pediatric surgeons and pediatric ear, nose, and throat (ENT) specialists. It basically includes daily examination for cranial nerve palsy, liquorrhea, and meningitis during hospitalization as well as routine audiometric examination and antibiotic prophylaxis. Routine vaccination against Streptococcus pneumoniae as a new standard procedure and subtotal petrosectomy after transverse fracture as a new surgical modality are strongly recommended in order to lower the incidence of posttraumatic meningitis. Severe complications such as persistent hearing loss, persistent liquorrhea, cranial nerve palsy, and posttraumatic meningitis require aggressive diagnostic and therapeutic measures in order to minimize further morbidity and irreversible deficits.

Adolescent↗
PubMed1994

Delayed cerebral infarction after dog bites: case report.

Delayed cerebral infarction occurred after dog bites in the region of the internal carotid artery of a 7-year-old boy. Initial wound exploration and repair did not reveal any signs of vascular trauma. Understanding the dynamics of the bites and relating the wounds topographically to the course of the underlying large vessels are key factors in early diagnosis of occult vascular damage.

Animals↗
PubMed1992

Current concepts in pediatric burn care: general management of severe burns.

Severe burns and scalds are still frequent. If the burn victim is a child, it should ideally be taken care of in a pediatric burn center, where both the burn and child-related needs are specifically met. The goals of burn care are to preserve life, to preserve function, to limit physical and psychological sequelae and to provide social reintegration. The system of burn care essentially consists of adequate initial resuscitation followed by early surgery aimed at rapid and definitive wound closure. Vigorous nutritional support as well as early rehabilitation and continuous psychosocial care are of paramount importance. The paper summarizes the essentials of pediatric burn care (burn surgery excluded).

Burn Units↗
PubMed1992

Current concepts in pediatric burn care: surgery of severe burns.

Optimal surgical therapy of severe burns in children has been controversial for a long time. A review of the current literature shows that prompt surgical excision of necrotic tissue and immediate autografting have become the standard in most burn centers. The authors present a concept based on prompt excision of third degree burns and discuss the problems of intermediate cover arising in massive burns.

Biological Dressings↗
PubMed1992

Current concepts in pediatric burn care: management of burn wounds with cultured epidermal autografts.

Our experience with CEA is based on 21 patients operated on from 1986 to 1991. The areas covered with CEA measured 500 cm2 to 3160 cm2. At one setting no more than 40 sheets of 40 cm2 CEA have been transplanted. The take of CEA is over 75% when applied to dermis. The same holds true when covering "deepithelialised" skin homografts on immunosuppressed patients. Scar formation has not been a problem, and the overall results have been good.

Adolescent↗
PubMed1991

Characteristics and prognosis of extradural hematomas in children.

This is a report on 31 children with operated extradural hematoma. The aim of the study was to elucidate the characteristics of extradural hematoma in childhood and the different clinical pattern and outcome compared to adults. For that reason the charts of the patients seen at the Department of Surgery of the Children's University Hospital Zurich between 1972 and 1990 have been revised. Follow-up criteria were recorded according to the Glasgow Outcome Scale. Most hematomas have been provoked by minor injuries and almost all children presented with at least one typical clinical sign. Associated intracranial injuries have been found in four patients, while two were polytraumatised. 30 of the 31 patients survived. One patient died of malignant brain edema. The mean range of follow-up was seven years. 28 patients had a "good recovery", "moderate disability" and "severe disability" was found in a patient one each. Our results demonstrate that the long-term outcome in children with extradural hematoma is far better than in adults regarding survival as well as quality of life. The causes may be minor traumas with fewer associated lesions and presentation with typical clinical findings and therefore early diagnosis and treatment.

Adolescent↗
PubMed1991

Reconstruction of skin and soft-tissue defects in crush-injuries of the lower leg in children.

Severe crush injuries with open comminuted fractures of the lower extremity often result in extensive tissue loss. In such a situation early free microsurgical tissue transplantation offers most effective possibilities of treatment. Among others, two of the most eminent advantages of free microsurgical tissue transplantation are: 1. The possibility of tissue replacement which cannot be achieved by traditional procedures such as functional muscle transplantation or the replacement of extremely extensive tissue loss; moreover immediate or early bone coverage by well vascularized soft-tissue is most effective in the prevention of infection. 2. In many cases complete reconstruction can be achieved by a one-stage-procedure: this decreases the morbidity considerably. These advantages are demonstrated by clinical cases, where we used free microsurgical tissue transplantation.

Amputation, Traumatic↗
PubMed1991

Traumatic spinal cord injury: unusual recovery in 3 children.

We report on 3 children with traumatic spinal cord injury. All of them had normal x-rays of the vertebral column. There were no abnormalities of the spinal cord in myelography or magnetic resonance imaging. Although these situations are often associated with a poor neurological prognosis, we observed very unusual recoveries in these 3 cases.

Child↗
PubMed1990

[Hematogenous bone and joint infections in children].

Not all children with osteomyelitis or septic arthritis will present with the characteristic findings, i.e. localized pain and swelling, fever and generalized malaise. Diagnostic problems arise in case of the following four special forms or locations of the diseases: neonatal osteomyelitis, because neonates frequently have no signs of infection; osteomyelitis of the spine and septic arthritis of the sacroiliac joint; subacute hematogenous osteomyelitis; chronic osteomyelitis. Acute bone and joint infections are diagnosed clinically. Positive blood cultures are found in only about half of all cases. Cultures of joint fluid or bone cultures are positive in 50 to 90%. The aim of therapy is to avoid destruction of bones or joints or even invalidity. Effective treatment consists of sufficient antibiotics for an adequate period of time and of immobilization. Surgical drainage is mandatory in case of abscess formation in soft tissue, of intramedullary or joint abscess, mainly hip-joint and shoulder, of persistent fever and in all chronic forms of osteomyelitis where areas of sequestra, dead tissue and abscesses may be assumed.

Abscess↗