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Biomedical subjects

R Sheridan

Publications and source records attributed to R Sheridan.

49 records · Page 3Linked to original sources
PubMed1979

LSH and FSH autonomous secretion in long-term pituitary tissue culture.

Pituitary tissue from 2- to 6-day-old male rats was cultivated for up to 136 days in medium containing fetal bovine serum, but without added steroid or hypothalamic extracts. After 40 to 70 days of sustained release of LH and FSH at a very low level, there was an increase in the quantity of both, and a plateau of depressed secretion. LH was identified by immunoreactivity in two radioimmunological systems and in gel chromatography. Little, if any, alpha-subunits were liberated in these cultures. It is concluded that basal production of LH and FSH is a constitutive activity of the gonadotropic cell.

Animals↗
PubMed1979

Autonomous secretion of follicle-stimulating hormone by long term organ cultures of rat pituitaries.

Pituitaries removed from ovariectomized adult rats were maintained for 18 weeks in organ culture using three different culture media. Gonadotropin secretion was assessed by RIA and was correlated with the histological features of the cultures. In medium favoring prolonged survival of the cultures, LH content of the medium fell to a low level within a few days. In the same cultures, FSH production initially decreased before increasing and leveling at a plateau which persisted until the end of the culture period. Cultures in medium unsuitable for long term survival of pituitary tissue displayed a similar decrease in LH production along with a gradual fall of FSH. It was concluded that contrary to LH, FSH may be secreted autonomously by pituitaries removed from hypothalamic control, provided that culture conditions are adequate for survival of gonadotropes.

Animals↗
PubMed1977

Synthesis and release of gonadotropins and their subunits by long-term organ cultures of human fetal hypophyses.

From weeks 13 to 26 of fetal life human hypophyses disclosed a constant content of radioimmunoassayable FSH. Although present already before this period, LH content increased considerably at week 17, along with the appearance of free beta-LH. In long-term organ culture experiments such early differentiating pituitaries proved to be endowed with autonomous synthesis and release of FSH and of free alpha-subunit, while LH, beta-LH and TSH declined to very low levels within a few weeks. Supplementation of the medium with LH-RH (12 ng/ml) significantly increased FSH synthesis and release but was not sufficient to sustain production of beta-LH and LH. It is suggested that other factors than LH-RH are required for differentiation of beta-LH biosynthesis and thus for production of LH.

Animals↗
PubMedDate not supplied

Packing and temporary closure in a liver injury.

As a component of a staged laparotomy for trauma, perihepatic packing can be lifesaving in the patient with exsanguinating liver injury who, due to hypothermia and coagulopathy, is unable to tolerate a more extensive procedure. However, if intra-abdominal pressure increases, the manoeuvre has been reported to compromise cardiopulmonary stability. Patients who suffer the adverse consequences of intra-abdominal hypertension are commonly managed with a loose temporary closure, frequently using an artificial material to bridge the skin defect across the incision. A case is reported where these two seemingly contradictory options were combined to achieve a successful outcome.

Accidents, Traffic↗
PubMedDate not supplied

A study on the erythrocyte aggregating properties of polybrene and protamine sulphate.

By observing the aggregation of erythrocytes in protamine sulphate or Polybrene it is possible to predict MN phenotypes with 97 per cent accuracy. It is probable that one factor influencing aggregation is the relative site density of a receptor common to both M and N antigen structures although other nondiscriminating receptor sites on a lower layer of sialic acid are possible also involved.

Acetylation↗
PubMedDate not supplied

Treatment of the seriously burned infant.

Infants (younger than 12 months) with large (more than 30%) burns are reported to have poorer chances for survival than older children with similar injuries. However, recent experience with such infants has been positive, prompting a 5-year review of management techniques. The injuries were approached in an organized fashion that included precise fluid support, excision, and biologic closure of full-thickness wounds within 5 days, limited exposure to high inflating pressures (more than 40 cm H2O), weekly replacement of central venous catheters, and intensive nutritional support via the enteral route whenever possible. Twelve such infants were treated during the 5-year interval. Their average age was 7.8 months (range, 1 to 12 month[s]), average weight was 8.8 kg (range, 4.3 to 13 kg), and average burn size was 42% (range, 30% to 90%). Inhalation injury was present in two of the children, and one child aspirated hot liquid. Six (50%) of the infants required the support of a mechanical ventilator for an average of 11.6 days (range, 4 to 18 days). Eight children required an average of 5.7 operations (range, 1 to 18 operation[s]), seven required central venous catheters, and five required arterial cannulae. Major infectious complications were seen in four children. Complications included pneumonia (two), catheter sepsis (two), peritonitis from a perforated ulcer (one), and wound sepsis (two). Six children required parenteral nutritional support for an average of 15 days (range, 5 to 36 days), and six children required enteral tube feedings for an average of 23 days (range, 9 to 55 days). Anabolic agents were not used. Discharge weights averaged 8.6 kg (range, 4.9 to 10.5 kg). The average ratio of the children's discharge to admission weight was 101% (range, 73% to 120%). All children survived and were discharged home. We conclude that these difficult injuries can be approached successfully with a strategy that emphasizes precise fluid repletion; early excision and biologic closure of wounds; avoidance of ventilator-induced lung injury; and intensive nutritional support.

Anti-Bacterial Agents↗
PubMedDate not supplied

Surveillance of burn wound infections: a proposal for definitions.

The diagnosis of burn wound infections is a subjective art, with no recent attempts to standardize or validate the definitions of terms used to discuss such infections. The Centers for Disease Control included definitions of types of burn wound infections in its definitions for nosocomial infections in 1988. Although the other Centers for Disease Control criteria for nosocomial infections have epidemiological applications, its criteria for burn wound infections have neither clinical nor epidemiological value to burn centers and their health care providers. With the approval of the Board of Trustees of the American Burn Association, the authors of this article formed a working subcommittee of the Committee on the Organization and Delivery of Burn Care. Definitions of burn wound infections are presented for consideration for application in either of 2 areas: (1) surveillance of burn wound infections in burn centers and (2) standardized criteria for multicenter clinical trials or national registries.

Burn Units↗
PubMedDate not supplied

Acellular allodermis in burns surgery: 1-year results of a pilot trial.

We grafted 10 sites on 6 children with limited (< 25%) areas of body surface available for donor harvest with an acellular allogenic dermis and a thin autograft. Matched control sites were grafted with autograft alone. Study site autografts (0.0074 +/- 0.0007 in, median 0.006 in, range 0.006 to 0.012 in) were thinner than control site autografts (0.0102 +/- 0.0008 in, median 0.012 in, range 0.006 to 0.013 in), with a P value of .015. Endopoints were initial engraftment (in percent) as judged by a blinded experienced observer and Vancouver scar scores. The 6 children (3 girls and 3 boys) had an average age of 5.2 +/- 0.9 years (range 2.8 to 10 years) and an average burn size of 68.7% +/- 6.7% total body surface area (range 47% to 85% total body surface area). The 10 study and control sites were treated with 10 separate procedures; 9 of the procedures were reconstructive and 1 was performed for the excision of an acute burn. Successful initial epithelialization was noted at 7 days postburn for 83% +/- 3.4% (range 60% to 95%) at the cryopreserved acellular human dermis sites and 83.3% +/- 4.3% (range 60% to 98%) at the control sites (not significant, P = .96). At a mean follow-up interval of 43.7 +/- 3.6 weeks (median 52, range 26 to 52 weeks), the differences between the study and control sites in the total mean (pigmentation, vascularity, pliability, and height) of the patients' Vancouver scar scores were not different.

Burns↗
PubMedDate not supplied

Early burn center transfer shortens the length of hospitalization and reduces complications in children with serious burn injuries.

Prompt transfer of the child with acute burns can be difficult from distant or inaccessible locations, and it is believed that the outcomes of children with serious burns whose transfer to a specialized burn care facility is delayed may be compromised. A 4-year experience with 16 consecutive children with serious burns (> or =20% of the body surface area) whose transfer to a burn care facility was delayed for 5 or more days was reviewed to document the difficulties that can follow such delays. These 16 children had an average age of 8.6+/-1.6 years and an average wound size of 57.6%+/-5.8% of the body surface area, and they arrived a mean of 16.3+/-3.4 days after the injury (range, 5 to 44 days). These children had undergone an average of 1 operation, excluding escharotomies, at referring facilities. Only 4 (25%) of the children had no infectious focus at transfer, and at admission resistant bacteria were recovered from 9 (56%) of the children and fungal organisms were found in 10 (63%). Compared with a concurrently managed matched control group of patients admitted to the burn center within 24 hours of injury, the delayed-transfer group had statistically significantly more bacteremia, renal dysfunction, wound sepsis, and central venous catheter days. It was also more expensive to manage these children; the delayed-transfer group required statistically significantly longer to achieve 95% wound closure, and they had greater total lengths of hospital stay and more rehabilitation days. The early transfer of children with serious burns to a specialized burn center may truncate hospitalization and thereby reduce costs.

Body Surface Area↗
PubMedDate not supplied

Management of background pain and anxiety in critically burned children requiring protracted mechanical ventilation.

Optimal control of pain and anxiety is an elusive but important goal in children with protracted critical illness. This review represents an effort to document the doses of background medication required to achieve this goal in a group of children managed under a pain and anxiety protocol that adjusts background infusions to comfort. The course of children with wounds involving at least 10% of the body surface and coincident respiratory failure requiring mechanical ventilation for more than 7 days managed 1 Jan 97 to 31 Dec 98 was reviewed. A pain and anxiety protocol was used, including background infusions of morphine and midazolam adjusted to comfort. These 28 children had a mean (+/- standard deviation) age of 5.3 +/- 4.6 years, wound size of 48.3 +/- 28.4%, and were intubated for 25.0 +/- 23.9 days. Neuromuscular blocking drugs were administered for 65 of 447 (14.5%) ventilator days. To maintain comfort, drugs were required at doses substantially above standard dosing schemes. The highest daily background infusion of morphine sulfate averaged 0.40 mg/kg/hr +/- 0.24 mg/kg/hr (usual starting dose was 0.05 to 0.1 mg/kg/hr) and was reached 14.1 +/- 12.8 days after admission. The highest daily background infusion of midazolam averaged 0.15 +/- 0.07 mg/kg/hr (usual starting dose was 0.04 mg/kg/hr) and was reached 14.0 +/- 3.8 days after admission. Morphine infusions at extubation averaged 0.22 +/- 0.17 mg/kg/hr and midazolam infusions 0.10 +/- 0.12 mg/kg/hr. All children survived to discharge and there was no perceived morbidity related to these high doses of medication. Children with serious burns and respiratory failure will require high doses of background opiates and benzodiazepines to remain comfortable, because they develop drug tolerance during protracted critical illness. Infusions can be continued at a reduced dose through extubation, do not result in addiction or other apparent morbidity if adjusted to desired level of comfort, and may contribute to a reduced incidence of treatment-related stress disorders.

Adolescent↗
PubMedDate not supplied

Initial experience with a prototype staple detector.

Stainless steel staples can be overgrown by granulation tissue or skin grafts and become buried in tissue. Although they are generally asymptomatic, they can on rare occasion erode to the surface or complicate the radiographic evaluation of pain not related to the staples. A device to facilitate detection of retained staples would be desirable, but it has been difficult to develop because stainless steel staples have poor magnetic and conductive properties. A prototype device, based on the presence of metal disturbing a low-power electromagnetic field, was developed. With human studies committee approval, this miniaturized detector was used in 13 burn patients to detect staples during planned removal of large numbers of staples. Staples were first removed using visual inspection and palpation of the wounds. This was followed by use of the staple detector. The age of the patients was 10.8 +/- 3.3 years, and burn size was 54.6 +/- 8.8% of the body surface. In 8 (62%) of the patients one or more additional staples were detected by the device that would otherwise have been overlooked. In 4 (31%) of the patients there was a false-positive signal, possibly related to topical silver in the wounds, that required additional focused physical examination. A portable staple detector has been developed. Initial experience with the device is favorable and warrants an expanded trial, which is in the planning stages.

Adolescent↗
PubMedDate not supplied

Early predictors of myoglobinuria and acute renal failure following electrical injury.

Myoglobinuria-induced acute renal failure (ARF) is a potentially lethal consequence of electrical injury. We describe clinical variables that can predict the risk of myoglobinuria and ARF following electrical injury. This was a retrospective multivariate analysis of risk factors among electrically injured patients over a 26-year period. Urine myoglobin status was documented in 162 patients; 14% had myoglobinuria. No patient developed ARF. Multivariate modeling revealed that high-voltage exposure, prehospital cardiac arrest, full-thickness burns, and compartment syndrome were associated with myoglobinuria. Using a prediction rule defined as positive when a patient had > or = 2 risk factors yielded a sensitivity of 96% and negative predictive value of 99%. Electrical injury patients with myoglobinuria have little risk of developing ARF. A prediction rule can be used to screen out patients at low risk for myoglobinuria and identify high-risk patients who warrant early aggressive treatment and a more definitive myoglobin test.

Acute Kidney Injury↗