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Biomedical subjects

D Silver

Publications and source records attributed to D Silver.

At least 91 records · Page 5Linked to original sources
PubMed1988

Should prophylactic anticonvulsants be administered to patients with newly-diagnosed cerebral metastases? A retrospective analysis.

We analyzed a retrospective series of 195 patients with documented intracerebral metastases (ICM) to assess the frequency of late seizure development and the impact of prophylactic anticonvulsants. Eighteen percent of the patients presented with seizures. Of the remaining patients, 40% received prophylactic anticonvulsants (diphenylhydantoin [DPH] in greater than 90%). Ten percent developed late seizures at an interval from the diagnosis of ICM ranging from 1 to 59 weeks. No patient with a posterior fossa lesion developed seizure; conversely, patients with evidence on initial examination of cerebral hemispheric dysfunction had a higher incidence of late seizure development. The incidence of seizure was virtually identical in patients who received DPH compared with those in whom it was withheld, although two thirds of patients who developed seizure while on DPH had a serum anticonvulsant level that was subtherapeutic. Based on the above findings and until prospective data become available, we recommend that anticonvulsants be withheld in newly-diagnosed patients with ICM until the first seizure.

Adult↗
PubMed1987

Reliability of continuous-wave Doppler probes.

Small-diameter, thin-walled latex tubes, through which a blood-simulating agent (0.1% suspension of simethicone in 0.9% sodium chloride) flowed at controlled rates, were embedded at varying depths in a tissue-mimicking matrix of powered graphite suspended in 4% agar. A continuous-wave (CW) Doppler probe was mounted at a 45-degree angle to the flow and passed transversely over the tube by a motorized drive mechanism at a rate of 0.42 mm/sec. Flow rates through the tubes were monitored with electromagnetic flow probes. The maximum depth from which quantitatively reliable signals could be obtained was 1.2 cm for 10 MHz probes and 3.3 cm for 5 MHz probes. Qualitative detection of flow was possible to a depth of 3.1 cm for 10 MHz probes and 7.0 cm for 5 MHz probes. The distances from the tube center for obtaining quantitatively reliable signals were limited to +/- 0.9 mm with a 10 MHz probe and +/- 1.8 mm with a 5 MHz probe. Qualitatively useful signals could be detected +/- 2.9 mm from the beam center by the 10 MHz probes and +/- 4.4 mm by the 5 MHz probes indicating a need for cautious interpretation as an interfering signal might be generated by any vessel within that range. Twenty percent of the randomly tested CW probes were considered unsuitable for use in quantitating blood flow, which underscores the importance of probe characterization before use.

Blood Flow Velocity↗
PubMed1987

The heparin-induced thrombocytopenia syndrome: an update.

One hundred sixty-nine patients with heparin-induced thrombocytopenia are reported and compared with the 62 patients reported in 1983. Prompt recognition of heparin-induced thrombocytopenia and immediate cessation of heparin administration lowered the complication and death rates from 61% (38/62) to 22.5% (38/169) and from 23% (14/62) to 12% (21/169), respectively. Platlet count and duration of heparin administration were not useful in predicting the outcome of the heparin-induced thrombocytopenia syndrome. Patients who received heparin in therapeutic doses were at higher risk for developing complications than were patients receiving lower doses of heparin. Platelet aggregation tests became negative as early as 7 days after discontinuation of heparin but persisted as long as 28 months. Heparin reexposure (2 days to 34 months after positive aggregation studies) was uneventful in 13 of 15 patients, whereas two patients suffered devastating thrombotic complications. Five patients continued to receive heparin despite positive platelet aggregation tests. The serious complications suffered by two of these five patients illustrate the necessity to discontinue heparin as soon as the diagnosis of heparin-induced thrombocytopenia is established.

Adolescent↗
PubMed1987

Spontaneous arterial perforation: the Ehlers-Danlos specter.

The Ehlers-Danlos syndrome (EDs) is one of the most frequently inherited disorders of connective tissue. Type IV EDs, the arterial-ecchymotic type, is of concern to vascular surgeons because it is frequently associated with spontaneous catastrophic bleeding. This article summarizes our experience with five members of a family and reviews the 31 patients with type IV EDs described in the literature. The 22 male and 14 female patients had a mean age of 26 years. The 36 patients included 23 with easy "bruisability," 22 with hypermobility of their joints (especially the fingers), 13 with transparent skin, and 11 with excessive elasticity of the skin. The patients had 41 episodes of hemorrhage and 29 vascular surgical procedures. Twenty-nine of the patients had an aneurysm or a dissection, whereas eight patients had arteriovenous fistulas. Arteriography was associated with a complication rate of 67%. The prognosis for a patient with type IV EDs is poor; 44% die before surgery and 19% die during the operative period. Bleeding should be managed nonoperatively when possible. Fifty-one percent die before reaching 40 years of age. Arteriography should be avoided. The standard repair of aneurysms and perforations is unlikely to be successful because of marked vessel friability. Bleeding vessels should be repaired with buttressed sutures and no tension or should be ligated. Genetic counseling with assay of collagen production is recommended for family members.

Adolescent↗
PubMed1987

Intimal integrity and fibrinolytic potential of reversed and in situ vein grafts.

The improved patency rates of in situ vein grafts are attributed to better flow characteristics, anastomotic "fit," and intimal preservation. This study compared the early changes in intimal morphology and fibrinolytic activity of in situ and reversed vein bypass grafts from mongrel dogs. Four to six centimeter in situ and reversed vein segments were used to bypass left and right femoral and internal carotid arteries, respectively. Heparin (100 U/kg) was administered before arterial clamping. Anastomoses were fashioned end to side and the intervening artery was ligated. Fifty-two grafts were harvested at day 1 (12 grafts), day 7 (16 grafts), day 14 (12 grafts), and 12 weeks (12 grafts). The veins were analyzed for histologic changes by light microscopy and scanning electron microscopy. The fibrinolytic activity of the grafts was assayed by the fibrin slide and fibrin plate techniques. There were no significant differences in morphology or fibrinolytic activity between the reversed and in situ grafts at any time period. These findings indicate that the improved patency rates associated with in situ grafts are not dependent on improved preservation of intimal structure or fibrinolytic activity.

Animals↗
PubMed1987

Intensive treatment of characterologically difficult patients. A general hospital perspective.

This article describes the development of a long-term inpatient treatment program in a general hospital setting for severely disturbed patients with personality disorder. A treatment model is outlined, with case vignettes included, that illustrates pertinent clinical issues. Also, the issue of regression in therapy, the role of consultation in a teaching unit, and research perspectives are discussed.

Adult↗
PubMed1986

Is thrombosis of the infrarenal abdominal aortic aneurysm an acceptable alternative?

Aortic aneurysm thrombosis with extra-anatomic bypass has been proposed for persons with infrarenal aortic aneurysms who are "too debilitated" to undergo standard aortic reconstruction. Thirteen patients (mean age, 75 years) were selected between January 1980 and June 1984 for axillobifemoral bypass with bilateral iliac artery occlusion to manage their infrarenal aortic aneurysms (mean size, 6.3 cm; range, 4.9 to 7.5 cm). Preoperative risk factors were cardiac (angina, compensated congestive heart failure, and significant preoperative arrhythmias), 100% of patients; pulmonary (symptomatic chronic obstructive pulmonary disease with a 1-second forced expiratory volume less than 50% of the predicted value), 46% of patients; renal (creatinine value greater than or equal to 2.0 mg/dl or creatinine clearance less than 20 ml/min), 46% of patients; or nutritional (albumin less than or equal to 3.5 gm/dl or body weight less than 90% of ideal), 46%. Ninety-two percent of the patients had two risk factors whereas 46% had three or more risk factors. The operative mortality rate was 31%; three patients died of multisystem organ failure and another died of thrombin-induced consumptive coagulopathy and hemorrhage. (Our operative mortality rate for conventional graft replacement of abdominal aortic aneurysms is less than 3%.) Morbidity in persons surviving at least 1 month included thrombosis of the extra-anatomic bypass graft requiring thrombectomy (three patients), ischemic colitis (two patients), ischemic neuropathy (one patient), and patients), ischemic colitis (two patients), ischemic neuropathy (one patient), and bilateral above-knee amputations (one patient). Thrombosis of the aneurysm was not achieved in two patients despite use of fluoroscopically controlled embolization of runoff vessels.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1985

Psychodynamics and psychotherapeutic management of the self-destructive character-disordered patient.

This article addresses some of the therapeutic strategies that the author has employed over the past number of years in treating a large number of patients usually referred to in the literature as having borderline or narcissistic personality disorders. The author refers to these patients as characterologically difficult. The focus of the treatment strategies is on the more fragile of these patients.

Borderline Personality Disorder↗
PubMed1984

Analysis of emotional status during the hospital treatment of a borderline patient.

This single case study illustrates a methodology for identifying recurrent pathological emotional states in a hospitalized, borderline patient. Parallel therapeutic inputs are delineated and examined in terms of patient-specific responses. The results indicate that ratings of nursing notes recorded across three periods of hospitalization can reliably isolate the patient's most salient and debilitating emotional states. State-specific therapeutic interventions are extracted and their effectiveness noted. The analyses illustrate clinical phenomena which are congruent with what is known about borderline symptomatology. In addition, the study locates therapeutic errors which often occur when working with difficult patients.

Adult↗
PubMed1984

Minimal size plasmids containing an M13 origin for production of single-strand transducing particles.

We have studied the requirements for efficient production of single-strand transducing particles from minimal size plasmids containing the phage M13 origin of replication. The most favorable origin fragment for production of transducing particles was found to extend from nucleotides 5372 to 5943 of the phage sequence, which includes a segment of the phage gene IV coding region and eliminates part of the gene II promoter. Minimizing vector size for M13 origin plasmids appears to be beneficial since transducing particle titer decreases with increasing plasmid size. A mutant helper phage was isolated and shown to improve the production of transducing particles from small plasmids, but to outcompete plasmids bearing large inserts. Several plasmid vectors which produce high yields of single-strand transducing particles and good ratios of transducing particles to helper phage have been constructed.

Coliphages↗
PubMed1984

Assessment of percutaneous balloon pulmonary and aortic valvuloplasty.

Percutaneous balloon pulmonary or aortic valvuloplasty was performed in 66 consecutive patients with no deaths. The transvalvular pressure gradient was reduced from 85 +/- 35 to 30 +/- 15 mm Hg (p less than 0.01) in 39 patients with congenital pulmonary valve stenosis and from 108 +/- 46 to 32 +/- 16 mm Hg (p less than 0.01) in 27 patients with congenital aortic valve stenosis. Subsequent mild aortic regurgitation occurred in seven patients and moderate regurgitation occurred in one patient. Operative evaluation of seven patients with pulmonary valve stenosis who had additional cardiac anomalies revealed the mechanisms of valve opening to be commissural splitting, cusp tear, or avulsion of the cusp from the anulus. Operative evaluation of two patients with residual high aortic valve gradients revealed minor degrees of commissural splitting. Although further evaluation is required to determine the long-term effects, early evaluation indicates that percutaneous balloon valvuloplasty may be useful in the definitive treatment of isolated pulmonary valve stenosis in some patients and of palliative value in others. The procedure is considered palliative in patients with aortic valve stenosis.

Adolescent↗
PubMed1984

Fibrinolytic response to trauma.

The fibrinolytic response to trauma was investigated in 23 patients. Patients were triaged upon arrival in the emergency center into three groups; group I-patients with significant trauma who maintained normal vital signs, had a good prognosis, and tolerated the trauma well (mean injury severity score 8, range 4 to 12); group II--patients with significant trauma and transient episodes of hypotension, hypoxia, or acidosis who recovered (mean injury severity score 22, range 9 to 38); and group III--patients with profound or continued hypoxia and hypotension who eventually died of the trauma (mean injury severity score 41, range 30 to 50). Serial measurements of prothrombin time, activated partial thromboplastin time, and platelet count; concentrations of fibrinogen, plasminogen, and fibrin degradation products; and assays of euglobulin fraction fibrinolytic activity on plasminogen-free and plasminogen-rich fibrin plates were obtained on all patients. Coagulation studies documented a trauma-related coagulopathy that correlated with the degree of trauma. Plasminogen concentrations were initially depressed in all three groups; however by 24 hours group III patients were noted to have significantly elevated plasminogen concentrations while group I and group II patients had normal plasminogen concentrations. Fibrinolytic activity measured on plasminogen-free and plasminogen-rich fibrin plates was initially increased in all three groups with group III patients demonstrating the greatest increase. Over the succeeding 14 hours fibrinolytic activity returned to baseline values in group I and group II patients while group III patients demonstrated no detectable fibrinolytic activity for the remainder of the study period. This absence of fibrinolytic activity and increase in plasminogen concentrations in group III patients is thought to be caused by depletion of the intravascular plasminogen activator with the subsequent development of a hypofibrinolytic state.

Blood Coagulation↗
PubMed1983

Heparin-induced thrombocytopenia, thrombosis, and hemorrhage.

Sixty-two patients with a heparin-induced thrombocytopenia are reported. Clinical manifestations of this disorder include hemorrhage or, more frequently, thromboembolic events in patients receiving heparin. Laboratory testing has revealed a falling platelet count, increased resistance to heparin, and aggregation of platelets by the patient's plasma when heparin is added. Immunologic testing has demonstrated the presence of a heparin-dependent platelet membrane antibody. The 20 deaths, 52 hemorrhagic and thromboembolic complications, and 21 surgical procedures to manage the complications confirm the seriousness of the disorder. Specific risk factors have not been identified; therefore, all patients receiving heparin should be monitored. If the platelet count falls to less than 100,000/mm3, while the patient is receiving heparin, platelet aggregation testing, using the patient's plasma, is indicated. Management consists of cessation of heparin, platelet anti-aggregating agents, and alternate forms of anticoagulation when indicated.

Adult↗
PubMed1983

Psychotherapy and the inpatient unit: a unique learning experience.

This paper describes the advantages of an inpatient setting for the teaching and learning of psychotherapy. Contributions to this process derive from the continuous and intense expressions of conscious and unconscious dynamics, transferences, and object relationships by the patients, the obligation on residents to therapeutically engage in a relatively exposed way with all the patients under their care, the availability and familiarity of the staff supervisors who participate in assessments and decisions regarding patient management and psychotherapy, and the collaborative work of all the other team members. Conditions of the setting which make this possible are the strong psychodynamic orientation of all the staff, the resident's role as manager and psychotherapist, the staff psychiatrist's role as supervisor and team leader, and the completely open communication among all the treating personnel.

Humans↗