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Biomedical subjects

D F Martin

Publications and source records attributed to D F Martin.

At least 37 records · Page 2Linked to original sources

Environmental impacts of phosphogypsum vs. borrow pits in roadfill construction.

A comparison was performed of the environmental impacts of using phosphogypsum versus conventional fill materials (e.g., from borrow pits) for road construction. The study compared a hypothetical roadway with an actual roadway in Florida; the two facilities differed only in that phosphogypsum was employed as fill material instead of conventional materials. The effect of the two construction approaches on the plant and animal communities was considered, as was the impact on the surface and ground water. A summary was made of the comparative impacts, and a comparison matrix was constructed using integral numbers to depict impacts ranging from -5 (most impact) to 0 (none) to + 5, showing most benefit of the part of the project on a given resource. Values were subjective, based upon investigators' experience. Four categories (plant and animal communities, water quality, water resources, and air quality) were considered. The cumulative total was +12 for phosphogypsum and -6 for conventional fill material.

Amphibians↗

Lysis of Gymnodinium breve by cultures of the green alga Nannochloris eucaryotum.

Laboratory cultures of Florida's red tide organism, Gymnodinium breve, were killed by the green alga Nannochloris eucaryotum. Studies involved organism-organism interaction as well as organism-cell-free culture (N. eucaryotum) interaction. Both studies demonstrated that N. eucaryotum adversely affected Florida's red tide organism. The lysis has been attributed to compounds called APONINs (apparent oceanic naturally occurring cytolins). N. eucaryotum crude APONIN was extracted from cell-free cultures, partially purified and fractionated. The fractions were bioassayed against G. breve, and 'fingerprints' of the deleterious fractions were obtained.

Animals↗

Critical micelle concentrations of allelopathic substances produced by Nannochloris oculata which affect a red tide organism, Gymnodinium breve.

Laboratory cultures of the green algae Nannochloris oculata and Nannochloris eucaryotum are known to cause lysis of Gymnodinium breve, which is Florida's red tide organism. Two cytolytic agents were previously identified as methyl palmitate and methyl stearate. In this study, the critical micelle concentrations of these substances were determined by ultraviolet light and turbidimetric methods to be 3.5 +/- 0.3 ppm (methyl stearate) and 4.3 +/- 0.6 (methyl palmitate). There were no significant differences in results obtained using the two methods.

Animals↗

Prevalence of antiviral drug resistance in untreated patients with cytomegalovirus retinitis.

The purpose of this study was to determine the prevalence of UL97 resistance mutations in cytomegalovirus (CMV) DNA amplified from the eyes of patients with AIDS and newly diagnosed CMV retinitis. Relevant segments of the CMV UL97 gene were amplified from vitreous humor, after which restriction digest screening was performed for resistance mutations at codons 460, 520, 591, 592, 594, 595, and 603. Mutations were confirmed by DNA sequencing. Vitreous from 21 eyes with AIDS-related non-CMV viral retinitis served as negative controls. CMV DNA was successfully amplified from 195 of 204 eyes. A resistance mutation was found in only a single eye, a T-->G mutation at base 1774, predicting a cysteine to glycine mutation at codon 592. The prevalence of UL97 resistance mutations in the eyes of patients with newly diagnosed CMV retinitis is very low.

AIDS-Related Opportunistic Infections↗

Technique for providing analgesia during percutaneous biliary interventional procedures.

AIMS: To evaluate the efficacy of interpleural analgesia during percutaneous transhepatic biliary procedures. METHOD: With the patient lying in the left lateral decubitus position a right sided interpleural catheter was sited at a chosen point between the 6th and 9th interspaces. Lignocaine was injected to provide a splanchnic and intercostal nerve block. The technique of interpleural block (IPB) is described. Assessment of the pulse, BP and O(2)saturation during the subsequent biliary procedure was made. The patient evaluated the maximum degree of pain felt during the biliary procedure according to a four-point pain scale (0-3). The nurse and radiologist also gave an objective assessment of the pain score. RESULTS: An IP catheter was successfully placed in 22 patients, one patient having the IPB on two occasions. Siting of the IP catheter failed in three patients. Good analgesia with no requirement for further analgesia or sedation was achieved in 11 patients on 12 occasions. Seven patients required additional small doses of analgesia for mild pain during the biliary procedure. IPB failed in four patients who required additional analgesia and sedation. No complication of the IPB technique occurred in our patient group. CONCLUSION: IPB is a safe and relatively effective method for analgesia during transhepatic percutaneous biliary procedures.

Aged↗

Diagnostic quality in endoscopic retrograde cholangiopancreatography: comparison between lodixanol and lopromide.

BACKGROUND AND STUDY AIMS: The contrast medium for endoscopic retrograde cholangiopancreatography (ERCP) must produce adequate images, whilst keeping the risk of complications to a minimum. There is a theoretical reason to suppose that a dimeric isosmolar medium may be superior to a monomeric hyperosmolar medium. We have compared two such media in a triple-centre double-blind randomized study on patients referred with a clinical indication for ERCP. PATIENTS AND METHODS: A total of 160 patients were randomly allocated to either lodixanol or lopromide. Assessments were made of the quality of images and the complications encountered. RESULTS: A total of 151 patients were evaluated. Apart from a trend towards better diagnostic quality for main pancreatic duct imaging with lodixanol, there were no differences between the two groups. The overall frequencies of adverse events were similar CONCLUSIONS: lodixanol is a safe and effective water-soluble contrast medium for ERCP, comparable to lopromide, but despite theoretical advantages lodixanol has no clear practical benefit.

Adult↗

Etiologic factors associated with anterior knee pain in distance runners.

PURPOSE: The objectives of this study were 1) to examine the differences between a noninjured (C) cohort of runners (N = 70) and runners afflicted with anterior knee pain (AKP) according to selected training, anthropometric, rearfoot motion, ground reaction force, and muscular strength and endurance variables; 2) to explore multivariate relationships among these measures in the well and injured groups; and 3) to develop specific hypotheses concerning risk factors for injury that will later be tested in a prospective clinical study. METHODS: High speed videography (200 frames x s(-1)), a force platform (500 Hz), and a Cybex II+ isokinetic dynamometer were used to assess rearfoot motion, ground reaction forces, and knee muscular strength and endurance, respectively. A linear discriminant function was performed on each of the five categories of variables and revealed 19 significant (P < or = 0.05) predictors. These variables were then combined and a final discriminant function analysis was performed. RESULTS: Pronation through the first 10% of stance, arch index, shoe mileage, and extension peak torque were the best overall (P < or = 0.05) predictors. The AKP group had smaller mean values on all four significant predictors. CONCLUSION: With the exception of shoe mileage, which is likely a response to rather than a risk factor for AKP, these results should prove useful to clinicians in identifying runners at risk for anterior knee pain.

Adult↗

A prospective randomised multicentre trial comparing 10 Fr Teflon Tannenbaum stents with 10 Fr polyethylene Cotton-Leung stents in patients with malignant common duct strictures.

BACKGROUND: Stent blockage is a multifactorial process in which stent design and materials, bacteria, proteins, and bile viscosity play a role. AIMS: To compare the patency of the 10 Fr Teflon Tannenbaum (TT) stent to that of the 10 Fr Cotton-Leung (CL) polyethylene stent with sideholes, in patients with malignant obstructive jaundice. METHODS: Patients were recruited to this prospective multicentre randomised study if they had a newly diagnosed malignant bile duct stricture below the hilum of the liver suitable for stenting with a 10 Fr stent. Data were collected and monitored by a professional monitoring company. Primary patency was the interval between stent placement and first exchange or death without recurrent jaundice. RESULTS: 134 consecutive patients were recruited between November 1994 and June 1997; 65 were randomised to the TT stent and 69 to the CL stent. Median patency and 95% confidence intervals were 181 (59, 303) days for the TT stent and 133 (92, 174) days for the CL stent, with no significant difference between the two stents (p=0.49). Median survival and 95% confidence intervals were 115 (71, 159) days for the TT stent and 151 (112, 190) days for the CL stent, with no significant difference between the two stents (p=0.765). CONCLUSION: Neither Teflon as a stent material nor the Tannenbaum design prolong the patency of plastic stents.

Adult↗

Bioassays of APONIN-3 and -4 with rabbit erythrocytes.

Rabbit erythrocytes in methanolic phosphate medium were used to bioassay the activity of authentic samples of methyl stearate and methyl palmitate (in 10% methanol:90% water, v/v), which had been identified as apparent oceanic naturally occurring cytolins (APONIN-3 and -4) produced by Nannochloris oculata. The two natural products are notable for cytolytic activity toward the unarmoured dinoflagellate, Gymnodinium breve Davis, an organism responsible for red tides consisting of harmful algal blooms in the Gulf of Mexico and along the eastern coast of the United States. Bioassays were done with heparinized rabbit blood. The absorbance at 540 nm was observed for 15 min in comparison with a sample treated with haemolysing agent. The results indicated that at reasonable concentrations of 1-10 ppm, neither was a haemolysin, although such concentrations caused cytolysis of G. breve cultures.

Animals↗

Oral ganciclovir for patients with cytomegalovirus retinitis treated with a ganciclovir implant. Roche Ganciclovir Study Group.

BACKGROUND: The intraocular ganciclovir implant is effective for local treatment of cytomegalovirus retinitis in patients with the acquired immunodeficiency syndrome (AIDS), but it does not treat or prevent other systemic manifestations of cytomegalovirus infection. METHODS: Three hundred seventy-seven patients with AIDS and unilateral cytomegalovirus retinitis were randomly assigned to one of three treatments: a ganciclovir implant plus oral ganciclovir (4.5 g daily), a ganciclovir implant plus oral placebo, or intravenous ganciclovir alone. The primary outcome measure was the development of new cytomegalovirus disease, either contralateral retinitis or biopsy-proved extraocular disease. RESULTS: The incidence of new cytomegalovirus disease at six months was 44.3 percent in the group assigned to the ganciclovir implant plus placebo, as compared with 24.3 percent in the group assigned to the ganciclovir implant plus oral ganciclovir (P=0.002) and 19.6 percent in the group assigned to intravenous ganciclovir alone (P<0.001). As compared with placebo, oral ganciclovir reduced the overall risk of new cytomegalovirus disease by 37.6 percent over the one-year period of the study (P=0.02). However, in the subgroup of 103 patients who took protease inhibitors, the rates of new cytomegalovirus disease were low and of similar magnitude, regardless of treatment assignment. Progression of retinitis in the eye that initially received an implant was delayed by the addition of oral ganciclovir, as compared with placebo (P=0.03). Treatment with oral or intravenous ganciclovir reduced the risk of Kaposi's sarcoma by 75 percent (P=0.008) and 93 percent (P<0.001), respectively, as compared with placebo. CONCLUSIONS: In patients with AIDS and cytomegalovirus retinitis, oral ganciclovir in conjunction with a ganciclovir implant reduces the incidence of new cytomegalovirus disease and delays progression of the retinitis. Treatment with oral or intravenous ganciclovir also reduces the risk of Kaposi's sarcoma.

AIDS-Related Opportunistic Infections↗

Self-expanding oesophageal metal stents for the palliation of dysphagia due to extrinsic compression.

The role of self-expanding metallic stents is well established in the palliation of oesophageal stenosis and dysphagia due to primary oesophageal malignancy. However, their role in palliation of dysphagia due to external compressive mediastinal malignancies is not well established. The purpose of this study was to assess the efficacy of self-expanding metallic stents in the palliation of dysphagia due to extrinsic oesophageal compression by mediastinal malignancy. Between January 1995 and January 1998, 21 patients with oesophageal compression due to malignant mediastinal tumours underwent oesophageal stent placement for palliation of dysphagia. Complete data were available in 17 patients (10 men and 7 women). The mean age was 63.5 years (range 46-89 years). A total of 19 stents were placed successfully. The dysphagia grade prior to and after oesophageal stent placement was assessed and the complications documented. Of the 17 patients, 16 reported an improvement in dysphagia. The mean dysphagia score improved from 3.1 prior to treatment to 1.3 after treatment. In 1 patient the stent slipped during placement and another stent was placed satisfactorily. Early complications (within 48 h) in the form of mild to moderate retrosternal chest pain occurred in 5 patients. This was treated symptomatically. Late complications (after 48 h) in the form of bolus impaction occurred in 2 patients. This was successfully treated with oesophagoscopy and removal of bolus. In 2 patients the stent was overgrown by tumour and in one of these an additional stent was placed. In 1 patient incomplete closure of a tracheo-oesophageal fistula was observed. There was no procedure- or stent-related mortality. The mean survival time of this group was 2. 1 months. Self-expanding metallic stents can be safely and effectively used in the palliation of dysphagia due to external mediastinal malignancies.

Aged↗

Use of the ganciclovir implant for the treatment of cytomegalovirus retinitis in the era of potent antiretroviral therapy: recommendations of the International AIDS Society-USA panel.

PURPOSE: To describe the risks, benefits, and recommended use of the ganciclovir implant for the treatment of human immunodeficiency virus-related cytomegalovirus (CMV) retinitis in the era of potent antiretroviral therapy. METHODS: A panel of physicians with expertise in the use of the ganciclovir implant and in the management of CMV retinitis was convened by the International AIDS Society-USA. The panel reviewed and discussed available data, and developed recommendations for the use of the ganciclovir implant, the surgical technique, and related management issues. Recommendations were rated according to the strength and quality of the supporting evidence. RESULTS: The effect of potent antiretroviral therapy on the immunologic status of patients with human immunodeficiency virus disease has changed the manifestation and course of CMV retinitis in many patients. The clinical management of CMV retinitis and the role of the ganciclovir implant are thus changing. Factors in the decision to choose the ganciclovir implant include the patient's potential for immunologic improvement, location and severity of CMV retinitis, and the risks and costs associated with implantation and concomitant oral ganciclovir therapy. CONCLUSIONS: The ganciclovir implant is safe and effective for the treatment of CMV retinitis. The indications for its use should be modified to account for increased patient survival and the potential for CMV retinitis to be controlled by effective antiretroviral therapy. Optimal use of the ganciclovir implant and discontinuation of therapy in selected patients with improvement in immunity may result in better long-term visual outcomes.

AIDS-Related Opportunistic Infections↗

Cat scratch disease: posterior segment manifestations.

OBJECTIVE: To evaluate the posterior segment findings seen in ocular cat scratch disease. DESIGN: Retrospective case series. PARTICIPANTS: There were 24 patients (35 eyes) with choroidal, retinal, or optic disc manifestations of Bartonella infection evaluated at the authors' institutions over a 6-year period. MAIN OUTCOME MEASURES: Clinical and photographic records were reviewed for evidence of disc edema, macular star, foci of retinitis or choroiditis, choroidal masses, optic nerve masses, vascular-occlusive events, or other findings. RESULTS: Discrete white retinal or choroidal lesions, 50 to 3000 microm in diameter, were the most common posterior segment findings in this series of patients (83% of eyes, 83% of patients). Optic disc swelling was the second most common finding (46% of eyes, 63% of patients) followed by a macular star (43% of eyes, 63% of patients). Vascular-occlusive events were also seen (14% of eyes, 21% of patients), and the site of occlusion was found to be intimately associated with the aforementioned retinal lesions. Final visual acuity was 20/25 or better in 26 (74%) of 35 eyes and was similar in both treated and untreated patients. CONCLUSION: Isolated foci of retinitis or choroiditis were the most common ocular manifestation of cat scratch disease in the authors' patient population, but an array of posterior segment findings may occur.

Adolescent↗

Etiologic factors associated with Achilles tendinitis in runners.

PURPOSE: The purpose of this study was to determine whether relationships exist between selected training, anthropometric, isokinetic muscular strength, and endurance, ground reaction force, and rearfoot movement variables in runners afflicted with Achilles tendinitis. METHODS: Specifically, we examined differences in selected measures between a noninjured cohort of runners (N = 58) and a cohort of injured runners with Achilles tendinitis (N = 31). Isokinetic, kinetic, and kinematic measures were collected using a Cybex II+ isokinetic dynamometer (Medway, MA), AMTI force plate (500 Hz), and Motion Analysis high-speed videography (200 Hz), respectively. Separate discriminant function analyses were performed on each of the five sets of variables to identify the factors that best discriminate between the injured and control groups. RESULTS: Years running, training pace, stretching habits (injured runners were less likely to incorporate stretching into their training routine), touchdown angle, plantar flexion peak torque at 180 degrees x s(-1) and arch index were found to be significant discriminators. CONCLUSION: A combined discriminant analysis using the above mentioned significant variables revealed that plantar flexion peak torque, touchdown angle, and years running were the strongest discriminators between runners afflicted with Achilles tendinitis and runners who had no history of overuse injury.

Achilles Tendon↗

Effect of injected versus iontophoretic corticosteroid on the rabbit tendon.

BACKGROUND: The etiologic role of corticosteroid therapy in tendon rupture is controversial. This study compared the effects of injected versus iontophoretically delivered corticosteroid on the normal rabbit Achilles tendon. METHODS: Rabbits were divided into three treatment groups: (1) corticosteroid injections, (2) iontophoretically delivered corticosteroid, and (3) no treatment. One tendon of each rabbit in the treatment groups was treated with either drug injection or iontophoresis; the tendon of the other leg served as a control. Some tendons were used for testing elastic modulus, ultimate load, and ultimate stress, while the remaining tendons were evaluated histologically. RESULTS: Injections of either corticosteroid or saline into the tendon sheath resulted in short-term changes in tendon biomechanical characteristics and somewhat higher histologic severity scores; however, iontophoretic delivery of corticosteroid or saline did not affect either significantly. CONCLUSIONS: Iontophoresis using sterile water or corticosteroid resulted in minimal or no biochemical and histologic changes in the tendon compared with injection of either substance. The method of corticosteroid delivery may be as important as the actual drug effects on the biomechanical and histologic properties of tendons.

Achilles Tendon↗

Radiological intervention in pancreatic cancer.

Pancreatic carcinoma is increasing in its incidence, and despite advances in surgical treatment and chemotherapy, its prognosis remains extremely poor. Realistic therapy is targeted primarily at the relief of obstruction of the biliary tract and the duodenum, as well as the relief of pain. This paper discusses the indications and techniques for palliation and illustrates the critical team approach between radiologist, endoscopist and surgeon.

Adenocarcinoma↗