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Biomedical subjects

A Langer

Publications and source records attributed to A Langer.

At least 127 records · Page 7Linked to original sources
PubMed1988

Absorbed dose to the fetus during bone scintigraphy.

The authors observed the uptake of radiopharmaceutical and calculated absorbed dose in fetuses of two patients who underwent bone scintigraphy with technetium-99m methylene diphosphonate. Dose estimates per administered activity were 17 mrad/mCi (4.6 microGy/MBq) for an 8-week-old fetus and 9.7 mrad/mCi (2.6 microGy/MBq) for an 18-week-old fetus. Neither fetus demonstrated radionuclide uptake above maternal background levels. The uterine activity showed rapid clearance, with an effective half-life of 12 minutes after reaching a maximum within 1 minute after injection. Major contribution to fetal dose comes from the presence of the radionuclide in the maternal bladder. The authors conclude that bone scintigraphy performed unknowingly in pregnant individuals presents negligible increased risk to the fetus.

Adolescent↗
PubMed1987

Detection of varicella-zoster virus in lymphocytes by DNA hybridization.

The availability of cloned varicella-zoster virus (VZV) DNA probes allows rapid detection of viral-specific DNA by "dot-blot" hybridization in lymphocytes or in lesion aspirates. Thirty-six blood specimens were obtained from 25 patients with suspected varicella or zoster. VZV-specific DNA was demonstrated in 15 lymphocyte preparations of nine patients with varicella and in one with disseminated zoster out of five patients with zoster. VZV-specific DNA was detected prior to rise in antibodies, indicating early viremia in these patients. Virus isolation from lesions and serological tests confirmed VZV infections. VZV-specific DNA was detected in lymphocytes of three patients out of six with active herpetic lesions, whereas it was not detected in lymphocyte specimens from two patients with undiagnosed rash or four with lymphoproliferative diseases, who did not present varicella or zoster, or from 18 healthy controls. No signal was obtained in herpes simplex virus (HSV)-infected and -uninfected cell lines. The hybridization assay proved that specific and viral or cellular DNAs other than VZV did not cross-hybridize with the probe. The sensitivity limit of detection was 4-15 pg of homologous DNA, and the assay was accomplished within 72-96 hr. These results point to the possible rapid diagnosis of VZV infection in patients suspected of varicella or generalized zoster. In addition, simultaneous infection with both VZV and HSV seems to occur in some patients.

Adolescent↗
PubMed1985

The effect of cyclosporin on murine autoreactive delayed type hypersensitivity induced with syngeneic lymphoblasts.

The effect of cyclosporin on an immunological autoreactive experimental model was analyzed. The experimental system consisted of X-irradiated A mice injected with syngeneic concanavalin A-induced lymphoblasts and footpad-challenged 7 days later with syngeneic lipopolysaccharide-induced lymphoblasts. 24-72 h after challenge, the footpads of these mice responded with significant swelling, accumulation of 125I-UdR or massive cellular infiltration revealed by histological examination. Since the immunological activity was transferred by Lyt-1+ T cells from the sensitized donors to naive recipients, we designated it 'syngeneic delayed-type hypersensitivity' (syn-DTH). This DTH was induced and elicited mostly by antigens of the syngeneic lymphoblasts and not by contaminants attached to them, indicating the immunological autoreactive nature of this system. Multiple doses of 60 mg/kg cyclosporin, given daily in the time interval between immunization and challenge, or on the last four days before challenge, inhibited the syn-DTH. Multiple injections of cyclosporin Before or close to the induction phase of the syn-DTH was ineffective, whereas single or multiple injections of cyclosporin close to the effector phase (the challenge time) markedly reduced the syn-DTH. Even a single injection of cyclosporin 24 h after the challenge efficiently reduced the 48-h syn-DTH. Adoptive transfer experiments revealed that T cells from X-irradiated mice immunized with concanavalin A-induced lymphoblasts and injected with cyclosporin, failed to efficiently transfer the syn-DTH response to naive recipients. Similarly, the syn-DTH response of naive X-irradiated recipient mice injected with cyclosporin, failed to be reconstituted with primed T cells derived from X-irradiated mice immunized with concanavalin A-induced lymphoblasts. Since the nonspecific footpad swelling response of X-irradiated mice challenged with lymphoblasts alone is resistant to the standard protocol of the cyclosporin treatment, we suggest that cyclosporin inhibits the ability of T cells to produce or release lymphokines at the effector phase of DTH, while phagocytic cells involved in the DTH response are not affected by it. The practical and the theoretical implications of this research are discussed.

Animals↗
PubMed1984

Chemopsychotherapy and its role in prosthodontic failures in elderly patients.

Since the introduction of chemopsychotherapy, there has been a change in the approach to treatment of mental and emotional disorders. Instead of being confined to mental institutions, many patients receive ambulatory treatment and are able to carry out their daily routine. Psychotropic drug therapy produces side effects in patients of all ages, but the incidence of side effects after the use of psychotropic drugs is significantly higher in older patients. In addition, the elderly population is more prone to mental disorders, either because of the worsening of conditions present at a younger age or because of changes related to the process of aging. These factors correlate with increased oral disability, which, although unrelated to the mental condition, is cumulative with time and age. Thus the number of elderly patients being treated for mental illness and simultaneously suffering from drug-related disorders of the stomatognatic system is high. Neurologic disorders may interfere with the patient's adjustment to removable dentures, which require a high degree of intricate muscular coordination during function.

Adult↗
PubMed1983

Successful management of a quadruplet pregnancy. A case report.

A quadruplet pregnancy was diagnosed by ultrasound antenatally and managed successfully in a community teaching hospital. The patient was hospitalized at 27 weeks' gestation. She was treated with a high-protein, high-calorie diet. Sonographic follow-up and monitoring of fetal growth were done, glucocorticoids were given to attempt to stimulate fetal pulmonary maturity, and Ritodrine was given orally as a prophylactic. On three occasions intravenous Ritodrine was used to inhibit premature labor. A well-organized delivery plan with interdepartmental cooperation achieved the successful delivery of four babies at approximately 33 weeks.

Adult↗
PubMed1982

The automatic implantable defibrillator. New Modality for treatment of life-threatening ventricular arrhythmias.

The automatic implantable defibrillator continuously monitors cardiac rhythm, identifies ventricular fibrillation and then delivers corrective defibrillatory discharges when indicated; it weighs 250 grams and has a volume of 145 cc. When a suitable arrhythmia is detected, a 25 Joule pulse is delivered through a superior vena cava catheter electrode and another electrode placed over the cardiac apex. As of March 1981, sixteen survivors of multiple cardiac arrests refractory to antiarrhythmic therapy had undergone implantation of the automatic defibrillator. There was no operative mortality and the morbidity was minimal. Electrophysiologic studies were performed before and after surgery to confirm failure of drug therapy and to ensure the device's ability to terminate malignant arrhythmias. Eight spontaneous and fourteen of the seventeen induced malignant arrhythmias were properly recognized and corrected by the device. The discharges were well tolerated by awake patients. A number of problems including recycling delays and spurious discharges have been identified and corrected. There were three late deaths with pulmonary edema noted in two patients, and asystole in one. The autopsies revealed no myocardial damage attributable to the automatic defibrillator. Although the ultimate role of this approach to prevention of sudden arrhythmic death has yet to be determined, the results obtained to date are encouraging and indicate that a useful modality for treating malignant ventricular arrhythmias has been added to our armamentarium.

Adolescent↗
PubMed1982

Ectopic pregnancy.

Management of ectopic pregnancy is tailored to the clinical situation. Improved sensitivity of human chorionic gonadotropin radioimmunoassay and radioreceptor assay and the use of gray-scale ultrasonography allow early diagnosis. Laparoscopy increases the diagnostic yield prior to rupture. Management is as conservative as possible to preserve fertility, Rho(D) immune globulin prophylaxis is mandatory if the patient is Rh negative.

Adult↗
PubMed1981

Telescope retainers for removable partial dentures.

Telescope crowns used in removable partial dentures reduce the destructive horizontal and rotational occlusal forces by directing them more axially and less traumatically than other retainers. These properties are combined with excellent conditions for cross-arch and multiple abutment splinting. If one of the abutment teeth needs extracting, the denture can be repaired with acrylic resin simply by remaking the secondary crown into a pontic. The single copings can be easily cleaned due to the good accessibility around their gingival margins. They also protect the abutment teeth against caries and thermal irritation. Soldering of the primary copings or their connection with accessory bars is not necessary in rigidly constructed telescope crowns, because the secondary crowns incorporated in the superstructure provide sufficient rigidity. In addition, the splinted copings often cause inflammatory gingival hyperplasia because the solder joints are too close to the gingival margins, preventing proper hygiene maintenance. The taper configuration or vertical height of the coping, which determines the amount of load transferred to each abutment, can be planned to suit each tooth's condition and designated function in the restoration. In a fixed restoration, the load is always evenly distributed among all the abutment teeth regardless of their condition, because the crowns are permanently cemented to them. In the telescope denture, the amount of force can be individually regulated by modifying the form and leverage of the retainers, according to their position, bone support, and occlusal conditions.

Crowns↗
PubMed1981

Tooth-supported telescope restorations.

Entirely tooth-supported removable dentures with telescope crowns may be considered a good alternative to a fixed restoration of the whole dental arch. They provide a rigid splinting and stable occlusion and offer a better safety factor owing to their removability and their lesser dependence on each single abutment. Also they are applicable when parallelism among the abutments does not permit making a fixed restoration. Furthermore they can be cemented in stages, decreasing the risk of washout later. Psychologically, they are well tolerated by patients.

Crowns↗
PubMed1981

The validity of maxillomandibular records made with trial and processed acrylic resin bases.

A comparison was made of the accuracy of maxillomandibular records made with trial bases fabricated on casts with blocked-out undercuts and those made with final processed bases. The results of the study indicate that significantly greater occlusal discrepancies occurred after the final processing when trial bases were used to obtain jaw records. With processed final bases, the denture superstructures are attached to the same bases used for recording, transferring, and adjusting the occlusion of the dentures. Thus, the dimensional changes of processing and the uneven setting of the bases upon the unevenly resilient mucosa are incorporated into both records and dentures. When placed in the mouth the conditions during and after fabrication are similar and occlusal discrepancies are minimal. With the trial base technique, the imperfections of both bases and clinical records are transferred to the final denture bases, which also have processing inaccuracies and which settle differently when placed upon the resilient tissue support. The divergent conditions created by the use of two types of bases are reflected in occlusal discrepancies of the completed dentures.

Acrylic Resins↗
PubMed1981

Lead systems for internal ventricular fibrillation.

We examined the feasibility of using a standby automatic implantable defibrillator and established thresholds for internal defibrillation. The implantable defibrillator senses ventricular fibrillation and delivers an electrical impulse for defibrillation. Two lead systems for the device have been investigated. System I consists of two 12-cm2 silicone-covered titanium mesh patches attached to the atrial and diaphragmatic pericardial surfaces. System II has an identical diaphragmatic patch and a titanium spring catheter, with a 12-cm2 surface area of conductivity, placed transvenously in the right atrium. Both systems were implanted by thoracotomy in 12 dogs (mean weight 20 kg) and by a subxiphoid approach in 10 pigs (mean weight 20 kg). The defibrillation threshold (lowest energy required for 80% success) was determined periodically for 54 weeks in the dogs (615 trials) and at 6 weeks for the pigs (100 trials). In dogs, the mean defibrillation threshold with system I leads at 4 weeks was 10.5 J and did not change significantly over a 54-week period (p greater than 0.05). Similar results were obtained in the pig at 4 weeks. The defibrillation thresholds for both lead systems in dogs and pigs using a transpleural thoracotomy or a subxiphoid approach are satisfactory for an implantable defibrillator that produces 20-35 J.

Animals↗