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Biomedical subjects

H Webster

Publications and source records attributed to H Webster.

18 recordsLinked to original sources
PubMed1998

Prefabrication of mucosa-lined flaps: a preliminary study in the pig model.

There is a need in reconstructive surgery for flaps lined by nonkeratizing stratified squamous epithelium or mucous membrane. Applications could be found in nasal, oral, genital, and esophageal reconstruction and even in reconstruction of hollow intra-abdominal tubes. Prefabrication of lined flaps has so far been limited to a pretransfer grafting of split-thickness skin. However, in certain situations this does not satisfy the primary requirement of replacing "like with like." Also, the availability of donor sites for harvesting mucosa is limited. The present study involves prefabrication of mucosa-lined flaps without causing donor site morbidity. The study was carried out on six mini-Hartford pigs. Buccal mucosa was harvested from the cheeks; the sheet was divided into several smaller graft pieces of 1 to 2 cm2 area. These graft pieces were then applied to the deep fascia at a distance of 5 to 15 mm from one another, also to galea, and to the undersurface of skin flaps. The grafted area was isolated from the opposing surface with a silicone sheet or Marlex mesh. The grafts were allowed to take and, it was hoped, merge together to form a sheet graft of dimensions greater than those of the original. Two to 7 weeks after the initial grafting, the skin flap was elevated; the mucosal grafts were observed macroscopically for take and surface area and microscopically to confirm that the lining was indeed mucosa. The mucosa took well on both the fascia and galea and also on the undersurface of the skin; it enlarged in size, and the small pieces became confluent to form a single sheet. The increase in surface area varied from 33 percent at 11 days postgrafting to a maximum of 238 percent after 7 weeks. All pigs had positive cultures from the mucosa before implantation but only one developed gross infection leading to partial graft loss.

Animals↗
PubMed1997

Persistence of neurotropic JC virus DNA in hamster tissues six months after intracerebral inoculation.

Immunostaining and polymerase chain reaction (PCR) methods were used to examine tissues from 18 6-month-old hamsters intracerebrally inoculated with JC virus (JCV) as newborns. JCV DNA was detected in all hamster brains and urinary bladders, as well as in most kidney, adrenal gland and pancreas samples. While results from reverse transcription PCR (RNA PCR) and immunostaining suggest that T antigen transcription and protein expression were restricted to the brain, the DNA suggests that intracerebrally inoculated JCV enters the systemic circulation and latently infects organs in a tissue specific manner.

Adrenal Gland Neoplasms↗
PubMed1995

Insulin-like growth factor I treatment reduces clinical deficits and lesion severity in acute demyelinating experimental autoimmune encephalomyelitis.

Our goal was to test the effects of insulin-like growth factor I (IGF-I) treatment on clinical deficits, lesion number and lesion size in acute demyelinating experimental autoimmune encephalomyelitis (EAE) induced in Lewis rats with an emulsion containing guinea pig spinal cord. In this EAE model, there is severe immune-mediated demyelination, which resembles that seen in actively demyelinating MS lesions. On day 12-13 after EAE induction, a total of 23 pairs of rats with the same mild degree of tail and hind limb weakness were given either intravenous IGF-I or placebo twice daily for 8 days. The daily IGF-I dose used in the first trial was 200 micrograms (about 0.6 mg kg-1) and in the second and third trials was 1 mg (about 3.0 mg kg-1). IGF-I treatment reduced permeability of the blood-spinal cord barrier to Evans blue-albumin. Maximum clinical deficit scores of IGF-I-treated rats were significantly lower and treated rats recovered faster than controls. IGF-I treatment produced significant reductions in weight loss and hind limb weakness. Treatment also improved treadmill walking, stride length and climbing performance. Morphometric analysis showed that spinal cord inflammatory lesions were significantly smaller and fewer in IGF-I-treated rats. The higher IGF-I dose produced a greater reduction in clinical and pathological deficits. We conclude that IGF-I treatment promotes clinical recovery by reducing EAE-induced blood-spinal cord barrier changes and the associated immune-mediated inflammatory lesions. Our results suggest that IGF-I may be useful in treating patients with multiple sclerosis and other demyelinating diseases.

Acute Disease↗
PubMed1993

Aneurysmal bone cysts in the hand treated by free non-vascular transfer of metatarsal or proximal phalanx from the foot.

Two cases of aneurysmal bone cyst in the hand are reported. In one case the entire first metacarpal was resected and grafted using the fourth metatarsal. In the second case diaphysectomy of the middle phalanx of the index digit was performed, and the proximal phalanx of the second toe was used as graft. Satisfactory length and function were maintained, the grafts remained viable and there was no donor site morbidity. Transplant of a metatarsal or toe phalanx to the hand, as a free non-vascularized graft, is a relatively straight forward operation, requires minimal refashioning of the graft, provides articular surfaces for joint reconstruction and leaves little donor site morbidity.

Adult↗
PubMed1993

Correlating infectious outcome with clinical parameters of 1130 consecutive febrile infants aged zero to eight weeks.

The study objectives were to characterize the infectious outcomes and associated clinical parameters of a large group of febrile young infants who received outpatient sepsis evaluation. This retrospective review of consecutive cases during a seven-year period was set in an urban pediatric emergency department. Febrile infants, aged zero to eight weeks, were the participants. All received a standard evaluation for sepsis, including complete blood count/blood culture, lumbar puncture/cerebrospinal fluid culture, and urinalysis/urine culture. Of 1130 patients, 447 (42%) were aged zero to four weeks, and 683 (58%) were aged four to eight weeks. In 96 cases (8.5%), a bacterial pathogen was isolated by culture of cerebrospinal fluid, blood, urine, or stool; 58% were aged zero to four weeks and 42% were aged four to eight weeks. The rate of positive cultures per patient age was doubled in those aged zero to four weeks (12%) compared with those aged four to eight weeks (6%). The 49 cases of invasive bacterial infections (bacterial meningitis/bacteremia) were most commonly associated with lower degrees of fever, as slightly over one half (25/49) had temperature < 39 degrees C. The most common pathogens of invasive bacterial infection were group B streptococcus and Escherichia coli, accounting for 33 of 49 cases (67%); the most common pathogens of invasive bacterial infection in older children (Haemophilus influenzae type b and Streptococcus pneumoniae) were relatively underrepresented, accounting for only five of these 49 (10%) cases.

Age Factors↗
PubMed1993

Physiologic monitoring of infants and children.

Accurate and safe monitoring of infants and children requires knowledge of their unique physiology, especially cardiovascular function, pulmonary physiology, and metabolic function. These individual features influence the equipment selection, as well as data interpretation. Although some adult equipment is adaptable for pediatric use, many specifications must be tailored to pediatric needs. Vascular monitoring in pediatric patients requires specific knowledge of insertion procedures and complications, fluid maintenance, and hemodynamic norms, indexed to body surface area. Valid data interpretation requires an understanding of the distinctive clinical responses intrinsic to the pediatric patient. Likewise, maintenance care for pediatric patients always includes attention to precise fluid balance, thermoregulation, and metabolic needs. Finally, all pediatric patients require constant vigilance to protect the integrity of their monitoring systems and, ultimately, the safety of these patients. Failure to address these concerns may result in complications or invalid data.

Adolescent↗
PubMed1990

In vitro activity of ramoplanin on staphylococci.

Approximately 1000 strains of staphylococci isolated from the skin of patients before and after coronary artery by-pass surgery were speciated using the API-Staph system, and tested for susceptibility to ramoplanin and teicoplanin. In addition flucloxacillin MICs were available for 750 strains. MICs were performed by incorporating dilutions of antibiotics in 'Isosensitest' Agar (Oxoid) and applying approx 10(4) cells by a multi-point inoculator. The strains tested (numbers in brackets) included: Staph. epidermidis (352), Staph. haemolyticus (133), Staph. simulans (104), Staph aureus (69), Staph. hominis (54), Staph. warneri (39), Staph. capitis (23), Staph. saprophyticus (12), Staph. cohnii (6) and Staph. sciuri (2). The overall MICs were: ramoplanin MIC 50%: 0.5 mg/l, MIC 90%: 1 mg/l; teicoplanin MIC 50%: 2 mg/l, MIC 90%: 8 mg/l. Ramoplanin MICs of greater than 2 mg/l were only found for 17 strains from eleven patients which included: Staph. simulans (6), Staph. haemolyticus (4) and Staph. epidermidis (2). The maximum MIC however was only 8 mgl, so no strains were ramoplanin-resistant. There was no relationship between ramoplanin and flucloxacillin MICs; but despite their differing modes of action, the strains with higher ramoplanin MICs also had higher teicoplanin MICs.

Anti-Bacterial Agents↗
PubMed1981

Immunocytochemical localization of P0 protein in Golgi complex membranes and myelin of developing rat Schwann cells.

P0 protein, the dominant protein in peripheral nervous system myelin, was studied immunocytochemically in both developing and mature Schwann cells. Trigeminal and sciatic nerves from newborn, 7-d, and adult rats were processed for transmission electron microscopy. Alternating 1-micrometer-thick Epon sections were stained with paraphenylenediamine (PD) or with P0 antiserum according to the peroxidase-antiperoxidase method. To localize P0 in Schwann cell cytoplasm and myelin membranes, the distribution of immunostaining observed in 1-micrometer sections was mapped on electron micrographs of identical areas found in adjacent thin sections. The first P0 staining was observed around axons and/or in cytoplasm of Schwann cells that had established a 1:1 relationship with axons. In newborn nerves, staining of newly formed myelin sheaths was detected more readily with P0 antiserum than with PD. Myelin sheaths with as few as three lamellae could be identified with the light microscope. Very thin sheaths often stained less intensely and part of their circumference frequently was unstained. Schmidt-Lanterman clefts found in more mature sheaths also were unstained. As myelination progressed, intensely stained myelin rings became much more numerous and, in adult nerves, all sheaths were intensely and uniformly stained. Particulate P0 staining also was observed in juxtanuclear areas of Schwann cell cytoplasm. It was most prominent during development, then decreased, but still was detected in adult nerves. The cytoplasmic areas stained by P0 antiserum were rich in Golgi complex membranes.

Animals↗
PubMed1980

Immunocytochemical method to identify myelin basic protein in oligodendroglia and myelin sheaths of the human nervous system.

To study the distribution of basic protein (BP) and other myelin constituents immunocytochemically in human nervous tissue, we modified the unlabeled antibody enzyme (peroxidase-antiperoxidase) method. The technique is described here. Because the availability of unfixed tissue from human central nervous system is limited, we tested the method on blocks that had been fixed in formalin and embedded in paraffin, fixed and stored in 4% formalin, or frozen at autopsy and stored. We obtained the best results with paraffin blocks. BP antiserum stained oligodendroglia and myelin sheaths in the developing human nervous system. In the adult, myelin sheaths were well stained. Also, abnormalities associated with myelin breakdown could be identified in multiple sclerosis lesions. The results suggest that this method will be useful in studying the cellular distribution of myelin components in human demyelinating diseases.

Adolescent↗
PubMedDate not supplied

Early enteral feeding in the pediatric intensive care unit.

BACKGROUND: The purpose of this study was to evaluate the feasibility and safety of early enteral feedings of critically ill pediatric patients. METHODS: The subject population of 42 critically ill patients ranged in age from 5 days to 18 years (mean 5.8 years), mean weight 17 kg. Transpyloric nasoenteric tubes were placed in all patients by a nonfluoroscopic bedside technique. All subjects were mechanically ventilated; 32 (76%) were on one or more vasoactive medications. Six (15%) patients were fed for more than 13 days while on vasoactive support and pharmacological paralysis. RESULTS: There were no documented complications of early enteral feeding, including aspiration. All patients were able to achieve caloric goals within 48 hours of beginning enteral feedings. All patients developed regular stool patterns despite periodic absence of bowel sounds. Enteral feedings replaced 256 days of total parenteral nutrition. Estimated patient charge savings averaged $425 for each day of enteral feedings. CONCLUSIONS: Early enteral feedings are feasible, well tolerated, and cost effective in critically ill pediatric patients.

Adolescent↗