Raising the operating table causing a sudden anesthesia system obstruction.
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Biomedical subjects
Publications and source records attributed to L Silver.
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Although many detection methods have been used to determine Helicobacter colonization in small animal models, the sensitivity and specificity of these detection methods are limited. To improve the Helicobacter felis conventional mouse model for accurate evaluation of therapeutic regimens, we developed a PCR for detection of, and a competitive PCR for quantitation of, H. felis in viral antibody-free (VAF) mice. The PCR was based on the H. felis 16S rRNA gene. An internal control DNA was used for competitive quantitation of the PCR. VAF conventional Swiss-Webster mice were infected with an H. felis culture by oral gavage. At various times after H. felis challenge and therapy, stomach mucosa was collected and evaluated by PCR. PCR detected approximately 50 to 100 H. felis cells per mouse stomach and showed no cross-reaction with other bacteria commonly found in mouse stomachs. Colonization of H. felis in the mouse stomach was confirmed by culture isolation from germfree mice and histological examination of VAF mice. Response to therapy in this H. felis model correlated well with results seen in human clinical trials with H. pylori. A model utilizing PCR detection which may be useful for discovering new antibiotics and/or vaccines against Helicobacter ulcer disease has been developed.
Viper venom disintegrins contain the RGD/KGD motif. They inhibit platelet aggregation and cell adhesion, but show structural and functional heterogeneity. We investigated the interaction of four prototypic disintegrins with alpha IIb beta 3 expressed on the surface of resting and activated platelets. The binding affinity (Kd) of 125I-albolabrin, 125I-echistatin, 125I-bitistatin and 125I-eristostatin toward resting platelets was 294, 153, 48 and 18 nM respectively. The Kd value for albolabrin decreased 3-fold and 6-fold after ADP- or thrombin-induced activation. The Kd values for bitistatin and echistatin also decreased with ADP, but there was no further decrease with thrombin. In contrast, eristostatin bound with the same high affinity to resting and activated platelets. The pattern of fluorescein isothiocyanate (FITC)-eristostatin and FITC-albolabrin binding to resting and activated platelets was consistent with observations using radiolabelled material. Eristostatin showed faster and more irreversible binding to platelets, and greater potency compared with albolabrin in inducing conformational neo-epitopes in beta 3. The anti-alpha IIb beta 3 monoclonal antibody OP-G2 that is RGD-dependent inhibited disintegrin binding to activated platelets more strongly than binding to resting platelets and it inhibited the binding to platelets of albolabrin more strongly than eristostatin. The specificity of disintegrin interaction with alpha IIb beta 3 was confirmed by demonstrating cross-linking of these peptides to alpha IIb beta 3 on normal platelets, but not to thrombasthenic platelets deficient in alpha IIb beta 3.
We sought to determine the prevalence of human immunodeficiency virus (HIV) infection in a population of women with human papillomavirus (HPV)-related diseases attending a colposcopy clinic who had no other CDC-defined risk factors for HIV. Study patients included all new patients attending our colposcopy clinic who were found to have histologic evidence of condyloma or cervical intraepithelial neoplasia. Those patients not already known to be HIV-positive were offered testing for HIV. Demographic information was obtained on all patients. Results were compared to data from anonymous testing of our own obstetrical population. One hundred forty of 208 women (67.3%) were either previously known to be HIV-positive or agreed to be tested. Sixteen (11.4%) were HIV-positive. Eight of the HIV-positive women were not previously known to be HIV-positive and 6 of the 8 had no definable risk factors for HIV infection. This is 4.6% of the women not already known to have a CDC-defined risk factor for HIV. The rate of HIV infection in our obstetrical population is 1.6%. In women without other definable risks for HIV infection and who had HPV-related disease the relative risk of HIV infection in our population was 2.94 (95% confidence interval 1.21-6.94; P < 0.031). In areas where HIV is endemic there is a high prevalence of HIV infection in women with HPV-related disease. Even in women without another definable risk factor for HIV, HPV-related disease may serve as a marker for an increased risk of HIV infection in this population.
The objective of this study was to characterize the effect of intravenous hypertonic sodium bicarbonate (NaHCO3) administration in patients with moderate-to-severe cyclic antidepressant (CA) overdose. We reviewed charts of all 91 patients given the diagnosis of CA overdose in the University of California Los Angeles (UCLA) Emergency Medicine Center (EMC), who either died in the EMC or were admitted to the medical intensive care unit (MICU), and who received NaHCO3 in the EMC between 1980 and 1988. Twenty-four other patients with the same EMC diagnosis were admitted to the MICU during this period but did not receive NaHCO3. The response of blood pressure, electrocardiographic parameters, and mental status to serum alkalinization with NaHCO3 were evaluated. Major morbidity and mortality were recorded for all patients. Hypotension was corrected within 1 hour in 20 of 21 (96%) patients, QRS prolongation corrected in 39 of 49 (80%), and mental status improved in 40 of 85 (47%). There was one death, in a patient who was moribund on arrival to the EMC. No complications were attributable to the administration of NaHCO3. NaHCO3 seems to improve hypotension and normalize QRS duration rapidly in most patients treated, and improve mental status changes in almost one half. Serum alkalinization with NaHCO3, in conjunction with appropriate supportive care, seems to limit major morbidity and mortality effectively in patients with serious CA overdose.
Previous studies demonstrated that Zn2+ at a concentration of 50 microM increases the number of fibrinogen receptors exposed on ADP-stimulated platelets and that higher concentrations of Zn2+ induce platelet aggregation that appears to be mediated by receptors associated with the glycoprotein IIb/IIIa complex. The purpose of this study was to identify the mechanism by which Zn2+ modulates exposure of fibrinogen receptors on the surface of human washed platelets. We determined that Zn2+ (300-800 microM)-induced platelet aggregation that was not accompanied by the release of [14C]serotonin was not blocked by ADP scavenging enzymes and 5'-p-fluorosulfonylbenzoyl-adenosine, an affinity label for ADP binding sites, but it was inhibited by disintegrins, staurosporine, and EDTA. Zn2+ (50-200 microM) showed a synergistic effect on platelet aggregation and platelet release caused by ADP and N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine, a Zn2+ chelator, and inhibited ADP-induced platelet aggregation that was reversed by Zn2+ (50 microM). Zn2+ (200 microM) increased the number of fibrinogen binding sites and the affinity of albolabrin (a disintegrin isolated from Trimeresurus albolabris snake venom that has been shown to bind to the fibrinogen receptor) on ADP-activated platelets. On the other hand, Zn2+ (100-800 microM) did not increase fibrinogen binding to the purified receptor. Incubation of platelets with Zn2+ (200 microM) resulted in the phosphorylation of a 47-kDa protein that was blocked by staurosporine, an inhibitor of protein kinase C. In conclusion, Zn2+ ions activate protein kinase C and enhance fibrinogen receptor exposure on the surface of platelets stimulated by ADP.
Proteus syndrome is a rare congenital disorder that is characterized by a wide variety of deformities including macrodactyly. Skin and soft tissue lesions are common; they may increase in size as the child develops and may assume tremendous proportions. The syndrome is often mistaken for other more commonly recognized conditions such as neurofibromatosis. Unlike neurofibromatosis, the soft tissue masses in Proteus syndrome are not nerve tumors but, rather, are hamartomas composed primarily of lipomatous tissue. The hand surgeon should be aware of this condition when evaluating a child with macrodactyly.
The treatment of 25 tibias in 25 patients with posttraumatic chronic osteomyelitis was reviewed. The approaches to soft tissue management fell into three groups: 1) muscle flap coverage; 2) primary closure with suction irrigation; and 3) open cancellous bone grafting. Treatment success was judged by the presence or absence of drainage and the local signs or symptoms of infection, and by the status of the tibial nonunion. Overall, 19 of 25 tibias (76%) had successful treatment. We found flap coverage to have a higher success rate (80%) than either primary closure with suction irrigation (45.5%) or open cancellous bone grafting (40%). These results further attest to the refractory nature of chronic osteomyelitis.
We have utilized several B-cell lymphomas that are growth inhibited by anti-Ig reagents as models for tolerance induction. In a previous communication, we demonstrated that the growth inhibition by anti-Ig can be partially prevented by the recombinant lymphokine, IL-4. In this paper, we report that complete protection of B lymphomas from anti-Ig was provided by a type 2 helper cell clone, D10.G4, when these T cells were activated by monoclonal anti-CD3. Conditioned medium from anti-CD3-stimulated D10.G4 cells also provided protection from anti-Ig. In contrast, little protection was observed with activated cells from a type 1 T-cell clone, A.E7. Furthermore, we show that combinations of IL-4 and tumor necrosis factors (both TNF alpha and TNF beta), as well as IL-4, effected partial protection by themselves and enhanced the activity of the other lymphokine if used in a pretreatment protocol. However, anti-cytokine antibodies were ineffective at reversing the T-cell-mediated protection. The possibility that direct T:B-cell contact mediates part of the protective signal is discussed.
The history of Diagnosis Related Groups (DRG's), a system for classifying patients in acute care hospitals, developed by researchers at Yale University, USA, is reviewed. DRGs are an instrument for measuring the hospital product, primarily from a management viewpoint. Starting with a review of the definitions of hospital product, the article follows the course from the first DRGs through the most recent revision, providing a summary of potential and current applications of the system in several countries, which range from payment mechanism to uses in quality control.
Rhegmatogenous retinal detachments can occur in patients with acquired immune deficiency syndrome (AIDS) and necrotizing retinal infections. Of 68 patients with AIDS and necrotizing retinal infections seen between 1983 and 1987, rhegmatogenous retinal detachments developed in 16 patients (27 eyes). In this group, cytomegalovirus retinopathy was present in 75% (12 of 16) of patients, 18.8% (3 of 16) had probable herpes simplex virus retinopathy, and 6.2% (1 of 16) had toxoplasmic retinochoroiditis. Retinal detachment was bilateral in 68.8% (11 of 16) of patients. The retina was reattached successfully in 91% (10 of 11) of operated eyes. Proliferative vitreoretinopathy was present preoperatively in 95% of these eyes. Seven of 11 operated eyes had initial improvement in visual acuity. However, 5 of 11 continued to lose vision despite successful reattachment. Techniques included pneumatic reattachment, scleral buckle, vitrectomy, and silicone oil injection. Complicated retinal detachments in AIDS patients with rhegmatogenous retinal detachments and necrotizing retinal infections are common and can be repaired, but the prognosis is guarded in many patients.
Antimicrobial research is geared toward the discovery and development of novel chemical structures such as therapeutic antimicrobial agents. The continuing problem of development of resistance to existing antibacterial agents and the dearth of good antifungal agents motivates this effort toward innovation. Selection of possible new enzyme targets for antibiotic inhibition may be made on theoretical grounds, but it appears premature to select any single, previously unvalidated target for the intensive study required for rational drug design. Instead, a broad screen of chemical entities can be undertaken, dedicated to the discovery of novel antimicrobial inhibitors. A number of target areas are under investigation, including fungal mRNA splicing and bacterial DNA synthesis. A major part of the endeavor is in the historically productive area of natural product screening. To make the best use of natural product resources for the discovery of novel antibiotics, a balance is struct between screening for inhibitors of rationally chosen targets for which clinically useful inhibitors are not yet available, and screening more broadly to ensure that rare activities of unanticipated mode-of-action are not missed.
Primary skin closure after the surgical correction of severe club-foot may be difficult. We describe the use of a tissue expander to provide sufficient skin, and review some aspects of the use of the method.
We reviewed written and audio records of paramedic-base hospital radio contact to determine whether care differed from that suggested in standard prehospital care protocols. Records of all 659 contacts for seizure, syncope, abdominal pain, or altered mental state during 1987 (28.4% of all contacts) were scored for the use of standard therapies (such as intravenous access, oxygen, naloxone hydrochloride) and unanticipated therapies (intubation, nitroglycerin). Cases that involved unanticipated treatments were reviewed to determine whether they could have been prospectively identified by simple clinical findings. Standard therapies were used in the majority of patients. Unanticipated therapies were administered to 13 patients, all of whom had abnormal vital signs, diaphoresis, respiratory distress, or a second prominent symptom. Data suggest that protocols could replace radio contact for most patients and that the few who might benefit from radio contact can be easily identified. A 90% reduction in radio contacts in Los Angeles county could save $3 million each year.
Pyomyositis is a Staphylococcus aureus infection of muscles reported primarily in tropical countries but seen with increasing frequency in temperate climates. Because of its rarity in the United States, the diagnosis may not be considered immediately, and involved muscles may break down and become abscessed. Diagnosis is most reliably made by the recovery of pus from a muscle aspirate. Ga-67 scan findings of an interesting case of pyomyositis involving many muscle groups in both upper and lower extremities is reported. Despite arthralgias and complicating adult respiratory distress syndrome, Ga-67 correctly localized the infection to muscles in the shoulders, upper thorax, buttocks, and thighs. A bone scan was negative, excluding the possibility of extension of the infection to bone.
The efficacy and safety of prazosin GITS (gastro-intestinal therapeutic system), a new extended-release once-a-day formulation, were assessed both as monotherapy in mild essential hypertension and in combination with a diuretic in moderate essential hypertension in two multicenter, double-blind, placebo-controlled trials. Prazosin GITS (Minipress XL) given once daily in doses of either 10 or 20 mg significantly reduced sitting and standing systolic and diastolic blood pressure compared with placebo in both mild and moderate essential hypertension. There were minimal, clinically insignificant changes in heart rate following prazosin-GITS treatment (2.5, 10, and 20 mg) compared with placebo treatment. Prazosin GITS was well tolerated; the most common adverse experiences reported were headache, dizziness, and fatigue. All adverse experiences in the moderate hypertension group and the majority (91 percent) in the mild hypertension group were mild-to-moderate in severity. The results from these multicenter trials demonstrate the efficacy and safety of this new extended-release once-a-day formulation of prazosin in the treatment of patients with mild and moderate essential hypertension.
Multiple thyroid carcinomas of divergent cellular origin are extremely rare. A case is presented in which two unrelated tumors, a medullary carcinoma and a papillary carcinoma, occurred as a collision tumor.
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