Biomedical subjects

Kerby C Oberg

Publications and source records attributed to Kerby C Oberg.

10 recordsLinked to original sources

PubMed2005

Dexamethasone alters vascular reactivity by enhancing COX-related vasodilatation in fetal ovine carotids.

Based on preliminary studies that contractile efficacy was altered in vertebral and basilar arteries from neonatal donors treated with postnatal glucocorticoids, we examined the hypothesis that postnatal dexamethasone (DEX), a glucocorticoid used for respiratory disease in neonates, can alter vascular reactivity. Using near-term fetal lamb carotids, we measured 5-hydroxytryptamine (5-HT) dose-response relationship in DEX-treated and untreated arteries. We found that DEX incubation for 1 h had no effect on 5-HT sensitivity and agonist affinity but significantly reduced 5-HT contractile efficacy, a response that became even more pronounced after 4 h of DEX treatment. Coincubation of DEX-treated arteries with INDO for 4 h reversed this DEX-induced attenuation in 5-HT contractile efficacy, although DEX had no significant effects on cyclooxygenase (COX)-1 and COX-2 protein abundance. This data suggests that DEX alters vascular reactivity through a COX-related mechanism, with possible repercussions to neurological injury.

Animals↗

PubMed2005

Cloning and functional study of porcine parotid hormone, a novel proline-rich protein.

A parotid gland hormone that stimulates intradentinal fluid movement is believed to play a significant role in maintaining the vitality of dentin. This hormone has been purified from porcine parotid glands and partially sequenced in our previous study (Tieche, J. M., Leonora, J., and Steinman, R. R. (1980) Endocrinology 106, 1994-2005). We now report the cloning and functional study of porcine cDNAs that code for this hormone and its complete amino acid sequence. Three cDNA clones were isolated from a porcine parotid cDNA library. The last 30 amino acids encoded by two of the cDNAs agreed with the amino acid sequence of the isolated parotid hormone. In situ hybridization and immunohistochemical staining demonstrated that the acinar cells of the parotid glands were the primary location for both the parotid hormone-related mRNAs and the translation products. A 216-bp fragment of the cDNA that contains the coding sequence for the porcine hormone was subcloned into an expression vector, and the protein expression was detected by immunoblot analysis and quantified by enzyme-linked immunosorbent assay. In addition, the 30-amino acid parotid hormone was synthesized. Both the expressed and the synthetic proteins were biologically active in that they enhanced intradentinal fluid movement as measured by intradentinal dye penetration.

Amino Acid Sequence↗

PubMed2004

Absence of robust ischemic preconditioning by five 1-minute total umbilical cord occlusions in fetal sheep.

OBJECTIVE: To determine to what extent a series of five 1-minute total umbilical cord occlusions, intended to induce ischemic preconditioning (IP), affects the physiologic responses to a 10-minute total umbilical cord occlusion (damaging insult [DI]) 1 hour later and provides cardio- and neuroprotection. METHODS: In 14 chronically catheterized late gestation fetal sheep (127-131 days' gestation), we performed a 10-minute total umbilical cord occlusion (DI), preceded by a series of five 1-minute total cord occlusions with 2-minute intervals (5CO, n = 7) or sham occlusions (n = 7) 1 hour prior to DI. RESULTS: The 5CO induced a reduction in the arterial partial pressure of oxygen (Po(2)) from 21 +/-1 to 14 +/-3 Torr, arterial O(2) content from 6.9 +/- 0.4 to 3.1 +/- 0.7 vol%, and increases in the partial pressure of carbon dioxide (Pco(2)) from 46 +/- 2 to 58 +/- 3 Torr, and [H(+)] from 43 +/- 1 to 54 +/- 2 nM. 5CO reduced fetal heart rate from 178 +/- 6 to 151 +/- 6 beats per minute (bpm), and increased arterial pressure from 45 +/- 1 to 57 +/- 2 mmHg, cerebral blood flow (CBF) from 100 +/- 3 to 129 +/- 10%, and cerebral heat production (H(brain)) from 25 +/- 2 to 29 +/- 1% degrees C. The responses to DI were not significantly different between the groups without and with 5CO; values for Po(2) were 5.6 +/- 1.5 and 5.8 +/- 1.9 Torr, O(2) content 0.6 +/- 0.1 and 0.8 +/- 0.1 vol%, lactate 10.7 +/- 0.7 and 10.8 +/- 0.7 mM, fetal heart rate 97 +/- 5 and 87 +/- 8 bpm, mean arterial pressure 22 +/- 3 and 21 +/- 2 mmHg, CBF 50 +/- 10 and 36 +/- 5%, and H(brain) 7.0 +/- 1.4 and 5.9 +/- 1.1% degrees C, respectively, except for Pco(2) (126 +/- 4 and 112 +/- 2 Torr) and [H(+)] (126 +/- 3 and 114 +/- 3 nM). Histologic proof of cardio- or neuroprotection by 5CO could not be obtained because five fetuses died before they were to be killed at day 3 after the experiment; two fetuses in the 5CO group demonstrated major histologic damage of myocardium and brain. CONCLUSION: In the late gestation fetal sheep, a series of five 1-minute total umbilical cord occlusions did not result in major changes in physiologic responses to a hypoxic-ischemic DI 1 hour later. In addition, the procedure did not result in robust cardio- and neuroprotection, in contrast to IP reported in adults.

Animals↗

PubMed2004

Lmx1b expression during joint and tendon formation: localization and evaluation of potential downstream targets.

The tetrapod limb exhibits distinct dorsoventral joint, tendon, and muscle asymmetry. The LIM-homeodomain transcription factor, Lmx1b, is required to achieve the dorsal character of these structures, but the mechanism by which Lmx1b orchestrates this asymmetrical development is unknown. To identify target tissues and genes regulated by Lmx1b, we examined Lmx1b expression during joint, tendon and muscle formation (9.5-16.5 dpc) and the expression of several genes spatially restricted to developing joints and associated tissues in normal and Lmx1b knockout (KO) mice including: Gdf-5, sFrp2, sFrp3, Six1 and Six2. Lmx1b was diffusely expressed in the undifferentiated dorsal mesoderm of the emerging limb bud (E9.5-E11.5). With progressive proximal to distal differentiation, Lmx1b expression localized to dorsal joint-forming regions, to developing tendons and ligaments, but not to migrating myocytes (E13.5-15.5). By E16.5, mature tendon and ligament associations were evident and Lmx1b expression had regressed. The expression patterns of Gdf-5 and sFrp3 at E15.5 were symmetrical along the dorsoventral axis in normal and Lmx1b KO mice. sFrp2, Six1 and Six2 exhibited asymmetrical dorsoventral expression and in Lmx1b KO mice, this asymmetry is lost; however, none were solely restricted to or excluded from dorsal Lmx1b expressing tissues.

Animals↗

PubMed2004

Aesthetic outcomes in patients undergoing breast conservation therapy for the treatment of localized breast cancer.

Localized breast cancer can be treated with lumpectomy and postoperative radiation therapy, also called breast conservation therapy, with an efficacy equivalent to that of mastectomy. Reports evaluating the effects of radiotherapy suggested that breast conservation therapy had "acceptable" cosmetic outcomes; thus, posttreatment evaluation for aesthetic impact has not been instituted as a standard of care. More recent reports have suggested that the effect of breast conservation therapy on aesthetic outcome is not minimal and that patients may benefit from reconstructive consultation. The purpose of this study was to measure objectively the aesthetic change in women who undergo breast conservation therapy and whether the extent of change is significant enough (objectively and subjectively) to warrant plastic surgery consultation. The authors evaluated 21 patients who had undergone breast conservation therapy. Eleven non-breast cancer patients seeking plastic surgery consultation were used as controls. Standardized five-view photographs (frontal, left and right lateral, and left and right lateral oblique views) were obtained. Patient photograph sets were compiled and evaluated independently by eight reviewers (four surgeons, two nurses, and two medical students). Reviewers evaluated the photographs using the breast asymmetry score (score range, 0 to 9) assessing breast size, ptosis, nipple-areola position, shape, scar appearance, contour deformity, and skin changes. The authors considered 2 SD above the control mean as significant. Breast conservation therapy patients also completed a 15-item questionnaire targeting objective and subjective data about treatment-related breast change. Breast conservation therapy patients had an average treatment-related asymmetry score of 1.93, with 35 percent demonstrating significant change as compared with controls. Although most patients (86 percent) were satisfied with the cancer treatment outcome, all patients noted asymmetry. The authors' data indicate that breast conservation therapy can cause significant asymmetry; thus, an option for plastic surgery consultation as part of the treatment protocol is warranted.

Age Factors↗

PubMed2003

A unique combination of infrared and microwave radiation accelerates wound healing.

Light or electromagnetic radiation has been reported to enhance wound healing. The use of selected spectra, including infrared and microwave, has been described; however, no studies to date have examined the potential benefit of combining these spectra. In this study, a device that emits electromagnetic radiation across both the infrared and microwave ranges was used. To test the effects of this unique electromagnetic radiation spectrum on wound healing, two clinically relevant wound-healing models (i.e., tensile strength of simple incisions and survival of McFarlane flaps) were selected. After the creation of a simple full-thickness incision (n = 35 rats) or a caudally based McFarlane flap (n = 33 rats), animals were randomly assigned to one of three treatment groups: untreated control, infrared, or combined electromagnetic radiation. Treatment was administered for 30 minutes, twice daily for 18 days in animals with simple incisions, and 15 days in animals with McFarlane flaps. The wound area or flap was harvested and analyzed, blinded to the treatment regimens. A p value of less than 0.05 obtained by analysis of variance was considered to be statistically significant. Animals receiving combined electromagnetic radiation demonstrated increased tensile strength (2.62 N/mm2) compared with animals receiving infrared radiation (2.36 N/mm2) or untreated controls (1.73 N/mm2, p < 0.001). Animals with McFarlane flaps receiving combined electromagnetic radiation had increased flap survival (78.0 percent) compared with animals receiving infrared radiation (69.7 percent) and untreated controls (63.1 percent, p < 0.01). Thus, combined electromagnetic radiation provided a distinct advantage in wound healing that might augment current treatment regimens.

Animals↗

PubMed2002

Efficient ectopic gene expression targeting chick mesoderm.

The chick model has been instrumental in illuminating genes that regulate early vertebrate development and pattern formation. Targeted ectopic gene expression is critical to dissect further the complicated gene interactions that are involved. In an effort to develop a consistent method to ectopically introduce and focally express genes in chick mesoderm, we evaluated and optimized several gene delivery methods, including implantation of 293 cells laden with viral vectors, direct adenoviral injection, and electroporation (EP). We targeted the mesoderm of chick wing buds between stages 19 and 21 (Hamburger and Hamilton stages) and used beta-galactosidase and green fluorescent protein (GFP) to document gene transfer. Expression constructs using the cytomegalovirus (CMV) promoter, the beta-actin promoter, and vectors with an internal ribosomal entry sequence linked to GFP (IRES-GFP) were also compared. After gene transfer, we monitored expression for up to 3 days. The functionality of ectopic expression was demonstrated with constructs containing the coding sequences for Shh, a secreted signaling protein, or Hoxb-8, a transcription factor, both of which can induce digit duplication when ectopically expressed in anterior limb mesoderm. We identified several factors that enhance mesodermal gene transfer. First, the use of a vector with the beta-actin promoter coupled to the 69% fragment of the bovine papilloma virus yielded superior mesodermal expression both by markers and functional results when compared with several CMV-driven vectors. Second, we found the use of mineral oil to be an important adjuvant for EP and direct viral injection to localize and contain vector within the mesoderm at the injection site. Lastly, although ectopic expression could be achieved with all three methods, we favored EP confined to the mesoderm with insulated microelectrodes (confined microelectroporation- CMEP), because vector construction is rapid, the method is efficient, and results were consistent and reproducible.

Actins↗

PubMed2002

ACTH-secreting islet cell tumor of the pancreas presenting as bilateral ovarian tumors and Cushing's syndrome.

A 41-year-old woman presented with hirsutism, a pelvic mass, and Cushing's syndrome. Imaging studies revealed bilateral ovarian masses and a solid and cystic mass within the pancreas. Partial pancreatectomy, bilateral oophorectomy, and excision of several peritoneal tumor nodules were performed. Pathological examination revealed a neuroendocrine islet cell tumor of the pancreas with bilateral ovarian metastases. The tumor was immunoreactive for ACTH, chromogranin, neuron-specific enolase, and keratin. The patient received postoperative chemotherapy and has been disease-free for 6 years. To our knowledge, this is the first reported case of an ACTH-secreting pancreatic neuroendocrine tumor presenting as bilateral ovarian metastases.

Adrenocorticotropic Hormone↗

PubMed2002

Necrotizing fasciitis: a fourteen-year retrospective study of 163 consecutive patients.

This review was prompted by continued public and professional interest of necrotizing fasciitis as well as worldwide increases in the incidence of streptococcal invasive infections. Our objective was to outline the clinical course of necrotizing fasciitis and delineate factors relating to mortality among 163 diagnosed patients. Over 14 years patients diagnosed with necrotizing fasciitis were reviewed for patient history, comorbid conditions, and progression of clinical course. A logistic regression model was used to identify factors increasing mortality risk among necrotizing fasciitis patients. Nearly 17 per cent of the patients showed no identifiable antecedent trauma. Seventy-one per cent of tissue culture-positive patients (145) had multibacterial infections. Although no streptococcal species were recovered from one-third of these culture-positive patients there was an increase in mortality noted with beta-Streptococcus infections. Ninety-six per cent of the patient deaths were correlated with variables organized into the following categories: 1) patient history (intravenous drug use and age <1 or >60 years), 2) comorbid conditions (cancer, renal disease, and congestive heart failure), 3) characteristics of clinical course (trunk involvement, positive blood cultures, peripheral vascular disease, and positive cultures for beta-streptococcus or anaerobic bacteria), and 4) quantitative timeline of clinical course (time: injury to diagnosis, diagnosis to treatment). Mortality is correlated to patient history, comorbid conditions, and progression of clinical course. Necrotizing fasciitis can occur idiopathically and is generally a polymicrobial infection that sometimes occurs in the absence of streptococci. Clearly the mortality and morbidity associated with necrotizing fasciitis can be decreased with clinical awareness, early diagnosis, adequate surgical debridement, and intensive supportive care.

Adolescent↗

PubMedDate not supplied

Surgical treatment of congenital syndactyly of the hand.

Syndactyly is a congenital anomaly of the hand that is more common in males, is present bilaterally in 50% of affected patients, and often is associated with other musculoskeletal malformations or systemic syndromes. The goal of syndactyly release is to create a functional hand with the fewest surgical procedures while minimizing complications. For simple syndactyly, surgical reconstruction can begin at approximately 6 months, although many surgeons prefer to wait until the infant is 18 months old. Special situations, such as complex syndactyly and involvement of border digits, may warrant surgical intervention earlier than 6 months. Reconstruction of the web commissure is the most technically challenging part of the operation, followed by separation of the remaining digits. Full-thickness skin grafting is almost always required for soft-tissue coverage. Complex syndactyly and syndactyly associated with other hand anomalies warrant special consideration. After reconstruction, patients should be examined periodically until they have achieved skeletal maturity because late complications such as web creep can occur.

Hand Deformities, Congenital↗