Search PubMed⌕ Search

Biomedical subjects

M D Davis

Publications and source records attributed to M D Davis.

At least 19 recordsLinked to original sources
PubMed2005

Comparison of specimen processing and nucleic acid extraction by the swab extraction tube system versus the MagNA Pure LC system for laboratory diagnosis of herpes simplex virus infections by LightCycler PCR.

A total of 563 specimens (234 dermal and 329 genital swabs) from patients suspected of having herpes simplex virus (HSV) infections were processed using two different extraction methods (the MagNA Pure LC system and the swab extraction tube system [SETS]); HSV DNA was amplified by LightCycler PCR. HSV DNA was detected in 157 of 563 specimens (27.9%) processed by the MagNA Pure LC system and in 179 of 563 specimens (31.8%) processed by SETS (P < 0.0001). There was no specimen processed by the MagNA Pure LC extraction method that was positive only for HSV DNA. Of 157 specimens positive by both methods, HSV DNA copy levels were higher (using cycle crossover points [cycle threshold {C(T)}]) with SETS (mean C(T), 25.9 cycles) than with the MagNA Pure LC system (mean C(T), 32.0 cycles) (P < 0.0001). The time to process 32 samples was longer with the MagNA Pure LC extraction system (90 min) than with SETS (35 min). HSV DNA extraction using SETS is faster, less expensive, and more sensitive than the MagNA Pure LC system and could replace the latter for the laboratory diagnosis of HSV infections using LightCycler PCR.

Clinical Laboratory Techniques↗
PubMed2002

Thermal inactivation D- and z-values of Salmonella serotypes and listeria innocua in chicken patties, chicken tenders, franks, beef patties, and blended beef and turkey patties.

Commercially formulated meat products, including chicken patties, chicken tenders, franks, beef patties, and blended beef and turkey patties, were obtained from processors. Each product was inoculated with 7 to 8 logs of Salmonella (Senftenberg, Typhimurium, Heidelberg, Mission, Montevideo, and California) or Listeria innocua. The inoculated meat samples were heat treated at 55 to 70 degrees C. At each temperature, the decimal reduction time (D) was obtained by linear regression of survival curves. Values of D and the temperature difference required for the thermal inactivation curve to drop a logarithmic cycle (z) were determined for the Salmonella serotypes and L. innocua in each product. At 55 to 70 degrees C. for the five tested products, the D-values for the Salmonella serotypes and L. innocua were 26.97 to 0.25 min and 191.94 to 0.18 min, respectively, and their z-values were 7.60 to 9.83 degrees C and 4.86 to 8.67 degrees C, respectively. Significant differences were found for the D- and z-values among the five products. This study will better enable processors to determine the process lethality of pathogens in commercial meat products.

Animals↗
PubMed2001

A Rep recognition sequence is necessary but not sufficient for nicking of DNA by adeno-associated virus type-2 Rep proteins.

The strand-specific, site-specific endonuclease (nicking) activity of the Rep68 and Rep78 (Rep68/78) proteins of adeno-associated virus type 2 (AAV) is involved in AAV replication, and appears to be involved in AAV site-specific integration. Rep68/78 cuts within the inverted terminal repeats (ITRs) of the AAV genome and in the AAV preferred integration locus on human chromosome 19 (AAVS1). The known endonuclease cut sites are 11-16 bases away from the primary binding sites, known as Rep recognition sequences (RRSs). A linear, double-stranded segment of DNA, containing an RRS and a cut site, has previously been shown to function as a substrate for the Rep68/78 endonuclease activity. We show here that mutation of the Rep recognition sequence, within such a DNA segment derived from the AAV ITRs, eliminates the ability of this substrate to be cleaved detectably by Rep78. Rep78 nicks the RRS-containing site from AAVS1 about half as well as the linear ITR sequence. Eighteen other RRS-containing sequences found in the human genome, but outside AAVS1, are not cleaved by Rep78. These results may help to explain the specificity of AAV integration.

Animals↗
PubMed2001

Partial unilateral absence of the trapezius muscle in a human cadaver.

We report here the partial unilateral absence of the trapezius muscle found during dissection. The left trapezius was significantly reduced in size when compared to the right trapezius, especially in its inferior third. Moreover, the existing fibers of the left trapezius inferior to the scapula were only one-third to two-thirds as thick as those on the right. The vertebral attachment of the inferior fibers of the left trapezius was also notably higher than that on the right. Morphometric analysis indicated that the surface area of the left trapezius was approximately 50% that of the right trapezius. Fiber orientation along the left and right trapezius muscles was also markedly different. An examination of nerve supply yielded no apparent anomalies, therefore suggesting that the absence of trapezius has a developmental etiology.

Aged↗
PubMed2001

Beard dermatitis due to para-phenylenediamine use in Arabic men.

The most common active ingredient in hair coloring is para-phenylenediamine (PPDA), which can produce contact dermatitis, particularly in persons who dye their scalp hair and in hairdressers. We have identified another group of patients also at risk, namely men from Arab countries, who commonly grow beards and dye them. We searched the computerized patient database at the Mayo Clinic for patients with beard dermatitis associated with dye use. Eight Arabic men presented to the Mayo Clinic between 1994 and 1999 with beard dermatitis and a positive patch test to PPDA. The lesions were described as pruritic, erythematous, papular eruptions that developed in the jaw area after each application of beard dye. The symptoms subsided after the patients discontinued use of the PPDA-containing dye and received treatment with topical corticosteroids. Allergic contact dermatitis in the beard area due to PPDA occurs in Arabic men as a result of their propensity to dye their beards.

Arabs↗
PubMed2001

Heat transfer properties, moisture loss, product yield, and soluble proteins in chicken breast patties during air convection cooking.

Chicken breast patties were processed in an air convection oven at air temperatures of 149 to 218 C, air velocities of 7.1 to 12.7 m3/min, and air relative humidities of 40 to 95%. The air humidity was controlled via introducing steam into the oven. The patties were processed to a final center temperature of 50 to 80 C. Heat flux, heat transfer coefficient, moisture loss in the cooked chicken patties, the product yield, and the changes of soluble proteins in the product were evaluated for the cooking system. During cooking, heat flux varied with the processing time. Heat flux increased with increasing air humidity. The effective heat transfer coefficient was obtained for different cooking conditions. Air humidity in the oven affected the heat transfer coefficient. The moisture loss in the cooked products increased with increasing the final product temperature and the oven air temperature. The soluble proteins in the cooked patties decreased with increasing the final product temperature. Increasing humidity increased heat transfer coefficient and therefore reduced cooking time. Reducing oven temperature, reducing internal temperature, and increasing air humidity increased the product yield. Soluble proteins might be used as an indicator for the degree of cooking. The results from this study are important for evaluating commercial thermal processes and improving product yields.

Animals↗
PubMed2001

Process lethality and product yield for chicken patties processed in a pilot-scale air-steam impingement oven.

Chicken breast patties were processed in a pilot-scale air-steam impingement oven to a patty center temperature of 55 to 80 degrees C. Thermal processing was conducted at an air temperature of 149 degrees C, an air velocity of 7 to 13 m3/min, and a wet bulb temperature of 39 to 98 degrees C. From thermal histories, the total process lethality of the patties was calculated for Salmonella spp. and Listeria innocua using the previously published z-values. The effect of product temperature, wet bulb temperature, and air velocity on process lethality was analyzed using a regression model. The process lethality of Salmonella spp. and L. innocua in the cooked chicken patties was correlated to the patty center temperatures and cooking conditions. The process lethality was strongly correlated to product temperature and was affected by cooking conditions. Process lethality started to increase rapidly at the product temperature around 67 degrees C. Regression analysis was used to correlate the product yield with cooking conditions. Depending on air velocity, product yield decreased 10 to 14% with increasing endpoint temperature from 55 to 80 degrees C and increased 2 to 9% with increasing wet bulb temperature from 39 to 98 degrees C. The effect of air velocity on the yield interacted with product temperature and wet bulb temperature.

Air↗
PubMed2001

Thermal lethality of Salmonella Senftenberg and Listeria innocua in fully cooked and packaged chicken breast strips via steam pasteurization.

Fully cooked chicken breast strips were surface inoculated to contain 9 log10 (CFU/g) Salmonella Senftenberg or Listeria innocua. The inoculated products were vacuum packaged in 0.2-mm-thick barrier bags (241 by 114 mm), then steam pasteurized at 88 degrees C in a continuous process for 26 to 40 min or in a batch process for 33 to 41 min. After the treatments, the products were analyzed for the survivors of Salmonella or Listeria. The models were developed to correlate the surviving rate of Salmonella and Listeria with cooking time for both continuous and batch processes. A cooking time of 34 min was needed to achieve 7 logs of the reduction in a batch process. To achieve the same log reduction, a longer (6 min) cooking time was needed in a batch process than in a continuous process. The results from this study will be useful for processors to evaluate postcooking treatment procedures for ready-to-eat meat products.

Animals↗
PubMed2001

Sézary syndrome: a summary.

Sézary syndrome is the leukemic form of primary cutaneous T-cell lymphoma. It is an aggressive disease, with the lowest reported median survival of all cutaneous lymphomas. Patients with Sézary syndrome live with the awareness that they are suffering from an incurable disease. Having to cope daily with extensive skin care regimens, these patients can benefit tremendously from the expertise of dermatology nurses, who can teach them skin selfcare and who are aware of the psychologic impact of this disease. The symptoms, treatments, and emotional distress related to Sézary syndrome are summarized.

Cortisone↗
PubMed2000

PD 158771, a potential antipsychotic agent with D(2)/D(3) partial agonist and 5-HT(1A) agonist actions. I. Neurochemical effects.

The neurochemical effects of a novel dopamine (DA) D(2)-like and serotonin (5-HT) 5-HT(1A) agonist, PD 158771, are described. PD 158771 exhibited affinities for human D(2L), D(3) and D(4.2) receptors expressed in Chinese hamster ovary (CHO)-K1 cells with K(i) (nM) values of 5.2, 13.7 and 34.8 respectively. PD 158771 showed high affinity for cloned human 5-HT(1A) (K(i) = 2.6 nM) and rat hippocampal 5-HT(1A) receptors (K(i) = 3.5 nM). Weaker affinities were observed at alpha 1-adrenergic (K(i) = 43 nM), histamine H(1) (IC(50) = 30 nM), 5-HT(2A) (K(i) = 24.5 nM) and sigma (sigma) -1 binding sites (K(i) = 24.5 nM). In measures of in vitro functional activity, PD 158771 stimulated [(3)H]thymidine uptake in CHO p-5 cells transfected with hD(3) receptors with a maximal effect of 23% relative to quinpirole. In hD(2)L, the corresponding value was 60% with an EC(50) of 29 nM, again indicating partial DA agonist action of PD 158771. In vivo, PD 158771 produced a dose-related decrease in DA synthesis in the striatum and mesolimbic regions of rat brain treated with gamma-butyrolactone (GBL), indicating a DA autoreceptor agonist action. In animals not treated with GBL, PD 158771 produced a dose-related decrease in DA synthesis and extracellular DA. A decrease in 5-HT synthesis in several brain areas was observed consistent with an agonist response. Further support for DA autoreceptor agonist action is that PD 158771 produced a partial inhibition of the firing of substantia nigra zona compacta DA neurons, an effect reversed by haloperidol. In conclusion, PD 158771 exhibited affinities for DA and 5-HT receptors, appears to possess DA and 5-HT agonist actions; and it could provide improved antipsychotic profile with minimal side effects.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed2000

Natural history of erythromelalgia: presentation and outcome in 168 patients.

OBJECTIVE: To describe the demographics, presentation, and outcome in patients with erythromelalgia--a rare and poorly understood clinical syndrome defined by the triad of red, hot, painful extremities. DESIGN: Retrospective medical record review with follow-up by survey questionnaire. SETTING: Large tertiary care medical center. SUBJECTS: Patients with erythromelalgia examined at the Mayo Clinic, Rochester, Minn, between 1970 and 1994. INTERVENTION: The medical records of 168 patients were analyzed. Follow-up data, which consisted of answers to 2 survey questionnaires or the most recent information in the medical record from patients still alive and death certificates or reports of death for those deceased patients, were obtained for all but 13 patients. MAIN OUTCOME MEASURES: Survival, morbidity, and quality of life. RESULTS: All patients were white; 122 (72.6%) were female, and 46 (27.4%) were male. At presentation, the patients' mean age was 55.8 years (age range, 5-91 years). Symptoms had been present since childhood in 7 patients (4.2%). Six patients (3.6%) had a first-degree relative with erythromelalgia. Symptoms were intermittent in 163 patients (97.0%) and constant in 5 (3.0%). Symptoms predominantly involved feet (148 patients [88.1%]) and hands (43 patients [25.6%]). Kaplan-Meier survival curves revealed a significant decrease in survival compared with that expected in persons of similar age and of the same sex (P<.001). After a mean follow-up of 8.7 years (range, 1.3-20 years), 30 patients (31.9%) reported worsening of, 25 (26.6%) no change in, 29 (30.9%) improvement in, and 10 (10.6%) complete resolution of the symptoms. On a standard health status questionnaire, scores for all but one of the health domains were significantly diminished in comparison with those in the US general population. CONCLUSION: Erythromelalgia is a syndrome with significantly increased mortality and morbidity compared with the US general population.

Adolescent↗
PubMed2000

Swelling and loss of photoreceptors in chronic human and experimental glaucomas.

OBJECTIVE: To determine whether outer retinal changes occur in chronic, presumed primary open-angle glaucoma (POAG). METHODS: The outer retinas from 128 human eyes with a diagnosis of chronic glaucoma (presumably POAG in most cases) and 90 control eyes were examined histologically by 3 masked observers for photoreceptor swelling and loss. Retinas from 9 rhesus monkeys with glaucoma induced experimentally by laser trabecular destruction were compared with 7 fellow (control) eyes. The mean pressure elevations in the eyes with laser trabecular destruction ranged from 26.6 to 53.6 mm Hg with durations varying from 7 to 33 weeks. RESULTS: Swelling of the red- and green-sensitive cones was observed in a statistically significantly greater proportion of human eyes with presumed POAG compared with the control eyes. Patchy loss of red/green cones and rods was also found in some of the glaucomatous retinas. In a subset of the human eyes with end-stage disease, cone swelling was a variable finding. Although no photoreceptor loss was found in the 9 monkey eyes with experimental glaucoma, 8 had swelling of their red/green cones that was remarkably similar to that seen in the human eyes. Swelling was not present in any of the control monkey eyes. CONCLUSIONS: The photoreceptors are affected by chronically elevated intraocular pressure. CLINICAL RELEVANCE: These findings may explain some of the abnormalities of color vision and the electrophysiological effects that have been observed in patients with POAG.

Aged↗
PubMed2000

Risk factors for advancement of cytomegalovirus retinitis in patients with acquired immunodeficiency syndrome. Studies of Ocular Complications of AIDS Research Group.

OBJECTIVE: To identify ocular and systemic factors that predict advancement of cytomegalovirus (CMV) retinitis during treatment. METHODS: Patients with acquired immunodeficiency syndrome were enrolled in a multicenter clinical trial designed to evaluate foscarnet sodium and ganciclovir sodium as therapy for newly diagnosed CMV retinitis. Ocular characteristics at baseline and measurements of retinitis were assessed from fundus photographs by graders at a fundus photograph reading center. The following measures of advancement were assessed: (1) lesion border movement of at least 750 microm or development of a new lesion in involved eyes; (2) rate of increase in retinal area with CMV in involved eyes; and (3) development of retinitis in uninvolved eyes of patients with unilateral disease at baseline. RESULTS: In eyes with retinitis, risk factors at baseline for advancement while receiving treatment included smaller area involved, active margins of retinitis, and posterior location. Risk factors for development of retinitis in uninvolved fellow eyes included blood and urine cultures positive for CMV and lower CD8(+) T-lymphocyte count. CONCLUSIONS: Lesion characteristics can be used to predict advancement of preexisting disease, whereas only systemic factors are associated with development of bilateral disease. These analyses describe retinitis activity before the introduction of potent antiretroviral therapies but provide an important reference point for patients in whom CMV retinitis develops after failure or intolerance of antiretroviral agents. Arch Ophthalmol. 2000;118:1196-1204

AIDS-Related Opportunistic Infections↗
PubMed2000

Infiltrating basal cell carcinoma in the setting of a venous ulcer.

A 77-year-old man was referred with a 5-year history of an intermittently painful, nonhealing right medial ankle ulcer. The ulcer had not responded to multiple treatment modalities, including Unna boots, compression therapy, sclerotherapy, and split-thickness skin grafting. The past medical history was significant for a deep venous thrombosis in the right leg 30 years earlier (treated with warfarin for 3 months) and a history of greater saphenous vein harvesting for coronary bypass grafting 28 years previously. After the vein stripping, the patient had suffered from increasing right leg edema and stasis changes in the right leg. His history was also remarkable for coronary artery disease, dyslipidemia, and lymphoma treated with chemotherapy 8 years before presentation, with no evidence of recurrence. He had stopped smoking approximately 20 years earlier. Medications included atenolol, simvastatin, nicardipine, nitroglycerin, and aspirin. Skin examination revealed a 3.0 x 3.5-cm ulcer adjacent to the medial malleolus. The edges of the ulcer appeared raised and rolled (Fig. 1). Centrally, there was granulation tissue, which appeared healthy. There were surrounding dermatitic changes. Dorsalis pedis and the posterior tibial pulses were normal. Noninvasive vascular studies revealed severe venous incompetence of the right popliteal and superficial veins. Arterial studies and transcutaneous oximetry were normal. Computed tomographic scan of the pelvis did not reveal any adenopathy, and radiographic imaging did not reveal any bony changes suggestive of osteomyelitis. Biopsy of the ulcer edge and base showed infiltrating basal cell carcinoma (Fig. 2). Mohs' micrographic surgery required three layers; the final extent of the ulcer was 7.8 x 6.9 cm. A split-thickness skin graft was placed.

Aged↗
PubMed2000

Large plantar wart caused by human papillomavirus-66 and resolution by topical cidofovir therapy.

Warts can be difficult to diagnose and to treat in the setting of human immunodeficiency virus (HIV) infection. A 37-year-old woman with a background of HIV presented with a large verrucous plaque involving her right foot. Human papillomavirus (HPV)-66 was identified in the lesional skin biopsy sample and in scrapings obtained from her cervix. The wart rapidly responded to topical cidofovir therapy. HPV-66 is a novel HPV type to be associated with verruca vulgaris. Topical cidofovir should be further investigated as an alternative treatment modality for verruca vulgaris.

AIDS-Related Opportunistic Infections↗