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Biomedical subjects

R Read

Publications and source records attributed to R Read.

At least 19 recordsLinked to original sources
PubMed2006

Detection and characterization of naturally acquired West Nile virus infection in a female wild turkey.

An adult female wild turkey exhibiting disorientation and failure to flee when approached was submitted to the Mississippi Veterinary Research and Diagnostic Laboratory. Gross pathologic examination revealed evidence of dehydration and the presence of modest numbers of adult nematodes in the small intestine. Histologic examination revealed extensive multifocal perivascular lymphocytic infiltration in brain, marked heterophilic hyperplasia in bone marrow, and multifocal interstitial lymphocytic infiltration in heart, pancreas, ventriculus, and skeletal muscles. West Nile virus (WNV) was isolated from the brain, lung, and kidney tissues using cultured Vero cells. Higher copies of viral RNA were detected from brain, lung, and kidney than from heart, liver, or spleen by quantitative real-time reverse transcription-polymerase chain reaction (RRT-PCR) analysis. Immunohistochemical (IHC) analysis detected WNV antigen in various tissues including neurons, kidney, respiratory tract epithelium, heart, and bone marrow. On the basis of the data from this investigation, it is concluded that WNV caused encephalitis along with many other pathologic changes in the affected wild turkey.

Animals↗
PubMed2005

Evaluation of healing in feline femoral defects filled with cancellous autograft, cancellous allograft or Bioglass.

Cancellous bone grafting is a widely accepted technique in human and veterinary orthopaedic surgery. However, the use of autogenous bone graft is limited by the additional surgical time required to harvest the graft, the morbidity associated with the donor site, and the limited availability of cancellous bone, especially in feline patients. Various allografts and bone graft substitutes are available commercially but have not been fully evaluated for efficacy in the cat. The purpose of this study was to compare the incorporation of autogenous and allogenous cancellous bone graft and Bioglass, a synthetic bone graft substitute, in femoral defects in cats. Four (4.0 mm diameter) defects were created in the lateral diaphyseal cortex of the left femur with an orthopaedic drill. In each femur, one of the cortical defects was filled with autogenous cancellous graft (harvested from the tibia), one was filled with allogenic cancellous graft, and one was filled with Bioglass. The fourth defect remained unfilled. Graft incorporation within the femoral defects was evaluated by radiographic evaluation every two weeks. Six weeks after the grafting procedure, the cats were euthanatized and high detailed radiography, dual energy X-ray absorptiometry (DEXA), histopathology and histomorphometry of the defects were performed. Satisfactory bone healing was observed within all of the defects.

Animals↗
PubMed2004

The control of Staphylococcus epidermidis biofilm formation and in vivo infection rates by covalently bound furanones.

In order to overcome the continuing infection rate associated with biomaterials, the use of covalently bound furanones as an antibiofilm coating for biomaterials has been investigated. Furanones have previously been shown to inhibit growth of Gram-positive and Gram-negative bacteria. The aim of these studies were to covalently bind furanones to polymers and to test their efficacy for inhibiting biofilm formation of Staphylococcus epidermidis and in vivo infection rate. Two methods of covalent attachment of furanones were used. The first, a co-polymerisation with a styrene polymer, and second, a plasma-1-ethyl-3-(dimethylaminopropyl) carbodiimide (EDC) reaction to produce furanone-coated catheters. Biofilm formation by S. epidermidis in vitro was inhibited by 89% for polystryene-furanone disks and by 78% by furanone-coated catheters (p<0.01). In an in vivo sheep model we found furanones were effective at controlling infection for up to 65 days. Furanones have potential to be used as a coating for biomaterials to control infection caused by S. epidermidis.

Animals↗
PubMed2004

The extent of ovarian damage produced by ovarian cauterisation in the human.

The object of this study was to assess the extent of ovarian damage produced by ovarian cauterisation. This was a prospective comparative study between four and eight holes using monopolar diathermy comparing the extent of damage of ovarian tissue in the human. The study was carried out in the department of obstetrics and gynaecology, Cairo University. We studied 50 patients aged 40-45 years who were scheduled for abdominal hysterectomy with bilateral salpingo-oophorectomy for benign gynaecological disease. One ovary was subjected to unipolar diathermy with four holes (group I) and the contralateral ovary involved eight holes (group II). The main outcome measured was the extent of ovarian damage produced by the cautery. The percentage area of cautery showed a median of 0.4% and a mean of 0.48% +/- 0.35 in group I, compared to a median of 1% and a mean of 1% +/- 0.31 in group II. The difference between the two groups is statistically significant (P < 0.001). The study suggests that the extent of injury to the ovary produced by cautery might be small, especially when using four holes; however, it is difficult to determine long-term host tissue response.

Adult↗
PubMed2003

Topographical analysis of the structural, biochemical and dynamic biomechanical properties of cartilage in an ovine model of osteoarthritis.

OBJECTIVE: The relationship between the topographical variations in the structural, biochemical and dynamic biomechanical properties of articular cartilage (AC) before and 6 months after meniscectomy has not been previously reported but is clearly relevant to our understanding of the role of mechanical factors on the pathogenesis of osteoarthritis (OA). The objective of this study was to address this deficiency using an ovine model of OA induced by bilateral lateral meniscectomy. DESIGN: The dynamic effective shear modulus (G*) and phase lag were determined ex vivo at 26 individual locations over the medial and lateral tibial plateaux of non-operated and meniscectomized ovine joints 6 months after surgery using a novel hand-held dynamic indentation probe. AC thickness was measured with a needle penetration probe. The AC from the same topographical locations as indented was then analysed for sulfated glycosaminoglycans (S-GAG) as a measure of proteoglycan (PG) levels, collagen and water content. Histological evaluation of the collagen organization using quantitative analysis of birefringence intensity was performed on stained tissue sections from the same topographical locations of each animal. RESULTS: It was demonstrated that the AC of the entire lateral tibial compartment of the meniscectomized joints underwent significant local degenerative and compensatory changes as indicated by a decreased G* and an increase in phase lag and water content. This was accompanied by a decrease in PG content of the AC of the middle and inner regions. While the AC of the outer region of the lateral meniscectomized compartment showed a marked increase in PG content and a more than two-fold increase in thickness, these tissues were also found to be structurally inferior, as indicated by a decreased G* and abnormal collagen birefringence intensity. The AC thickness was elevated at all locations of the lateral and medial tibial plateau of the meniscectomized joints. Strong and significant correlations between the biomechanical and biochemical data were established for a number of the parameters examined, especially between collagen content and G*, collagen content and AC thickness, and G* and AC thickness. An inverse correlation between S-GAG content and G* was only apparent in non-operated control tissues, whereas correlations between collagen and water content, water content and G*, and water content and thickness were evident for AC of the meniscectomized tibial plateaux. Less striking changes were noted in the medial compartment where the intact meniscus remained in place. However, elevated PG content, thicker AC together with slight changes in G* suggested an early hypertrophic response in these tissues. CONCLUSION: This study has highlighted the variable response of AC in different topographical regions of meniscectomized joints to the altered mechanical stresses introduced by this surgical procedure. The AC at the joint margins, while thicker and richer in PG, was found to be biomechanically softer (lower shear modulus) than normal AC, and because of this, would be expected to undergo degenerative changes with time leading to the onset of OA.

Animals↗
PubMed2002

Phase I/II trial of outpatient docetaxel, cisplatin, 5-fluorouracil, leucovorin (opTPFL) as induction for squamous cell carcinoma of the head and neck (SCCHN).

The purpose of this study was to establish the maximum tolerated dose (MTD) of docetaxel in an outpatient docetaxel (T), cisplatin (P), 5-fluorouracil (5-FU) (F), and leucovorin (L) (opTPFL) regimen and to obtain preliminary assessment of opTPFL efficacy. Thirty-four patients with stage III or IV squamous cell carcinoma of the head and neck were treated with opTPFL. Docetaxel was escalated from 60 to 95 mg/m(2) in combination with 100 mg/m(2) cisplatin intravenous bolus, and 2,800 mg/m(2) 5-FU continuous infusion and 2,000 mg/m(2) leucovorin continuous infusion with prophylactic growth factors and antibiotics. Patients who achieved a complete (CR) or partial (PR) response to three cycles received definitive twice-daily radiation therapy. A total of 97 cycles were administered to 34 patients. The major acute toxicities were neutropenia and mucositis. The MTD of docetaxel was 90 mg/m(2) . Seventy-seven of 97 cycles of were administered on an outpatient basis. The overall clinical response rate to opTPFL was 94%, with 44% CRs and 50% PRs. The MTD of opTPFL is 90 mg/m(2) docetaxel. Outpatient administration of opTPFL is tolerable, feasible, and does not alter the ability to administer definitive radiation therapy on schedule.

Adult↗
PubMed2001

Hypothyroidism incidence after multimodality treatment for stage III and IV squamous cell carcinomas of the head and neck.

PURPOSE: Treatment of head-and-neck cancer patients with surgery, radiotherapy (RT), and chemotherapy has been associated with posttherapy hypothyroidism (HT). We evaluated the rate of posttherapy HT in patients with locally advanced squamous cell carcinoma of the head and neck, treated with multimodality therapy to determine which factors might predict this condition and at what interval the condition developed. METHODS: We reviewed the prospectively collected thyroid function data of patients treated with sequential chemotherapy, RT, and neck dissection. The incidence of posttherapy HT was estimated. The patient, tumor, and treatment factors possibly associated with HT were evaluated. RESULTS: Of 203 patients, 118 had data adequate for evaluation. HT developed in 45% at a median of 24.4 months after therapy. HT occurred in 14% and 27% of patients at 6 months and 1 year after treatment, respectively. Univariate and multivariate analyses of sex, age, RT dose, RT fractionation, T and N stage, tumor site, and neck dissection failed to identify a clinically relevant risk factor. CONCLUSIONS: A high number of patients undergoing aggressive organ-sparing multimodality therapy for advanced squamous cell carcinoma of the head and neck are at risk for subsequent HT. We recommend that all patients definitively irradiated to the head and neck region undergo frequent serum thyroid-stimulating hormone screening for HT, beginning 6 months after RT.

Analysis of Variance↗
PubMed2000

The Drosophila primo locus encodes two low-molecular-weight tyrosine phosphatases.

The fine modulation of tyrosine phosphorylation by protein tyrosine phosphatases and protein tyrosine kinases is a key regulatory mechanism for many cell signaling pathways active during development. In a screen for genes with interesting expression patterns in the developing Drosophila pupal retina, we identified a novel pair of protein tyrosine phosphatases that exhibit an expression pattern suggesting a role in multiple steps of Drosophila neurogenesis. Together, these phosphatases define the primo locus. Their sequence is approx. 50% identical to each other and to low-molecular-weight protein tyrosine phosphatases (LMW-PTPs) identified in other species. Little is understood of the biological role of LMW-PTPs, and the powerful tools available in Drosophila should provide important insight into their role in signaling and development.

Amino Acid Sequence↗
PubMed1999

An evaluation of anterior temporal and masseter muscle activity in appliance therapy.

Needle electromyography (NEMG) was used to compare the effects of the Hawley bite plane (HBP) and superior repositioning splint (SRS) on the ipsilateral masseter and anterior temporal muscles at rest and in maximum closure. Twenty adult subjects were randomly divided into two groups of 10. One group wore the HBP for 8 hours per day and the other group wore SRS for the same time period. After 2 weeks of use, NEMG was conducted on the ipsilateral masseter and temporal muscles with and without the device in place. Each group then wore the other appliance for an identical period and underwent NEMG. Both appliance designs produced decreases in electromyographic responses during use. Individuals in the HBP group showed a 48.6% decrease in anterior temporal activity and a 34.1% decrease in masseter muscle activity. The SRS group demonstrated 23.5% and 16.2% decreases in anterior temporal and masseter muscles activities, respectively. This is the first report of the use of NEMG as a mode of assessment of muscle activity in human or animal subjects.

Adult↗
PubMed1999

Phase II trial of docetaxel, cisplatin, fluorouracil, and leucovorin as induction for squamous cell carcinoma of the head and neck.

PURPOSE: To evaluate the toxicity and efficacy of a 4-day regimen of docetaxel, cisplatin, fluorouracil, and leucovorin (TPFL4) in patients with locoregionally advanced squamous cell carcinoma of the head and neck (SCCHN). PATIENTS AND METHODS: Thirty previously untreated patients with stage III or IV SCCHN and Eastern Cooperative Oncology Group functional status of 2 or less were treated with TPFL4. Postchemotherapy support included prophylactic growth factors and antibiotics. Patients who achieved a complete response (CR) or partial response (PR) to three cycles of TPFL4 received definitive twice-daily radiation therapy. The primary end points were toxicity and response to TPFL4. RESULTS: Eighty-five cycles were administered to 30 patients. The major acute toxicities to TPFL4 were mucositis and nausea. One patient died of neutropenic sepsis during therapy. Additional major toxicities were neutropenia, anorexia, nephropathy, neuropathy, and diarrhea. Fourteen percent of all cycles were associated with hospitalization for toxicity. The overall clinical response rate to TPFL4 was 93%, with 63% CRs and 30% PRs. Primary tumor site clinical and pathologic response rates were 93% and 68%, respectively. CONCLUSION: TPFL4 has an acceptable toxicity profile in good-performance-status patients. Modification of the 5-day TPFL regimen (TPFL5: shorter chemotherapy infusion time, earlier intervention with growth factors and antibiotics) led to fewer episodes of febrile neutropenia and hospitalization. Response rates to TPFL justify further evaluation of combinations of these agents in the context of formal clinical trials.

Adult↗
PubMed1997

Use of fine needle aspiration for solid breast lesions is accurate and cost-effective.

BACKGROUND: Palpable breast tumors have traditionally been diagnosed with open biopsy or core biopsy. We propose fine needle aspiration biopsy (FNA) as a reliable, cost-saving initial procedure in these patients. METHODS: Eighty-five palpable solid breast masses of the breast in 85 patients were classified by a combination of physical examination, mammography, and/or ultrasound as probably benign, indeterminate, or highly suspicious for cancer. All tumors had FNA biopsies. All patients had either a confirmatory open biopsy (55) or close clinical follow-up (30) with a mean follow-up of 29 months (range 6 to 36). RESULTS: Thirty-four patients classified as clinically benign had a benign FNA biopsy. No cancers were detected in this group by either open surgical biopsy or clinical follow-up. Twenty patients were classified clinically as indeterminate. All had FNA biopsies, and 6 were either positive for cancer or suspicious for cancer. Fourteen patients had negative FNA biopsies. Five of the 6 abnormal biopsies had cancer on open biopsies. The 1 false-positive result occurred in a lactating patient. Thirty-one patients were classified clinically as highly suspicious for cancer. Twenty-three were confirmed as cancer with FNA biopsy. Eight needed open surgical biopsy to confirm cancer. All 31 patients clinically suspicious for cancer had cancer. In patients classified clinically as highly suspicious or probably benign, FNA was a reliable first diagnostic step (100% positive predictive value, 100% specificity, 87% sensitivity, and 89% negative predictive value). CONCLUSIONS: Fine needle aspiration biopsy of solid palpable breast lesions should be the diagnostic procedure of choice for those patients classified clinically as probably benign or clinically as highly suspicious for cancer. Cost analysis revealed elimination of an open biopsy in such cases would save $1,100 per patient. For highly suspicious cases, a negative fine needle aspiration should not deter an open surgical biopsy. For patients classified as indeterminate, fine needle aspiration biopsy results are not reliable enough to determine treatment.

Biopsy, Needle↗
PubMed1997

Validity and reliability of the MTI photoscreener.

OBJECTIVES: The prevalence and necessity for early detection of vision problems illustrate the need for improved methods of vision screening in preschool children. This study assessed the validity and reliability of a new device, the MTI photoscreener in a cross-sectional field study. METHODS: An appropriate sample size (> 140) was calculated and recruited for the study. All children (N = 161) in a migrant workers summer education program were screened with the MTI Photoscreener. Simultaneously and in a masked design, disease status was determined by the Modified Clinic Technique, a well established method for diagnosing the conditions which the MTI screener was designed to detect. RESULTS: Validity measures revealed a sensitivity of 54%, specificity of 87%, phi coefficient of 0.40, and positive predictive value of 52%. Repeatability was assessed by the kappa coefficient, by a test for effect modification by examiner, and by comparison of sensitivity and specificity across 12 masked examiners. The kappa coefficient was 0.38. A test for effect modification suggested that differences existed among the examiners. Variability of sensitivity was high, but variability of specificity was low. CONCLUSIONS: Methods for vision screening in preschool children are limited. The MTI Photoscreener is an easy and efficient method, but the validity and reliability is a concern. Comparison of our results with other studies suggests future potential for this instrument provided protocols are refined and further field studies reveal efficacy.

Child↗
PubMed1996

Response to oral and intravenous azithromycin in a patient with toxoplasma encephalitis and AIDS.

We present a patient with AIDS and toxoplasma encephalitis who was unable to tolerate established therapy with sulphadiazine or clindamycin but responded to oral azithromycin and pyrimethamine. The patient was maintained on oral azithromycin but subsequently relapsed after 8 months. The recurrence was successfully treated with intravenous azithromycin. The case illustrates that azithromycin can be used to treat patients with toxoplasma encephalitis who are unable to tolerate or fail to respond to other therapeutic agents. Failure of oral azithromycin may be due to inadequate tissue concentrations and patients may further benefit from intravenous administration.

AIDS-Related Opportunistic Infections↗
PubMed1995

beta-Cyclodextrin: 52-week toxicity studies in the rat and dog.

A 52-wk toxicity study by dietary administration was performed in Sprague-Dawley rats and in pure-bred beagle dogs with beta-cyclodextrin, a starch derivative that acts as a molecular inclusion agent. Doses of 0 (control), 12,500, 25,000 and 50,000 ppm were selected for the rat study, and 0 (control), 6200, 12,500 and 50,000 ppm were selected for the dog study. The liver and kidney were identified at the histopathological examination as target organs for toxicity in the rat at doses of 50,000 and 25,000 ppm, with the hepatic changes associated with increased plasma liver enzyme and reduced plasma triglyceride concentrations. In the dog study, there was no pathological evidence of systemic toxicity, although there were minor changes in urinalysis and biochemical parameters and a slightly higher incidence of liquid faeces. These changes were considered to be of no toxicological importance. The results in these studies, therefore, indicate that the non-toxic effect level was 12,500 ppm in the rat (equivalent to 654 or 864 mg/kg/day for males or females, respectively) and 50,000 ppm in the dog (equivalent to 1831 or 1967 mg/kg/day for males or females, respectively).

Analysis of Variance↗
PubMed1995

Hyaluronic acid (hyaluronan) in experimental osteoarthritis.

We studied the effects of intraarticular (ia) administration of hyaluronic acid (HA) (Mw approximately 9 x 10(5)) (Artz) on cartilage integrity and release into synovial fluid (SF) of keratan sulfate peptides (KS-pep) in an ovine model of early osteoarthritis (OA) induced by meniscectomy. Five consecutive weekly injections of HA (2 ml, 10 mg/ml) or saline (2 ml) were initiated 16 weeks after meniscectomy, and animals were sacrificed 5 weeks after the last injection. SF was sampled 8, 16, 23, and 26 weeks postoperation. In the saline injected animals KS-pep levels increased progressively in SF, relative to nonoperated controls (p < 0.05). KS-pep levels in SF of the HA treated group also increased, but were not statistically different from controls. Using a modified Mankin histological scoring system, cartilage at necropsy of HA injected joints showed less damage than similar regions of saline treated animals. A new mechanism for the protective effects of HA on cartilage is proposed.

Animals↗