Biomedical subjects
Publications and source records attributed to S Klein.
The Jena ophthalmospectrometer was used to investigate type I and II diabetics with and without retinopathy and normal persons. Discriminant analysis allows separation of normals and diabetics with a high degree of sensitivity and specificity. In diabetics, spectrometric changes precede ophthalmoscopically visible changes.
Clostridial bacteremia is rare and has a variable presentation from asymptomatic to septic shock with disseminated intravascular coagulation (DIC), red cell hemolysis, and rapid death. In order to delineate the predisposing and prognostic factors in these patients, the authors reviewed 47 cases of clostridial bacteremia presenting over a seven year period at a major metropolitan teaching hospital. Predisposing factors included locally decreased oxidation reduction potential (Eh) in 43 per cent (including atherosclerosis, diabetes, and radiation therapy), systemic immunosuppression in 53 per cent (including alcohol abuse, chemotherapy, steroids, and malignancy), and a site of epithelial barrier disruption. The sites of clostridial invasion included: gastrointestinal tract (GI) (n = 22), pulmonary (n = 7), cutaneous (n = 7), undetermined (n = 7), and female genital tract (n = 4). Seven patients were found to have malignancy. Seventy-nine per cent of the blood culture isolates were histotoxic species (Clostridia perfringens and C. septicum). The overall mortality was 47 per cent. Significant differences between survivors and deaths included DIC, new onset renal failure, severe atherosclerotic disease, and age (P less than .05). The authors conclude that clostridial bacteremia is uncommon but highly lethal and may occur when decreased tissue Eh, systemic immunosuppression, and an epithelial barrier disruption are present. Poor outcome appears to be a reflection of advanced age, underlying illness, and presence of a histotoxic species.
Calcium-independent calcium efflux from heavy sarcoplasmic reticulum (HSR) of skeletal muscle was found to be biphasic, with half-times of 2-6 s and 200-400 s for the first and second phase, respectively. Calcium-, AMP- and caffeine-induced calcium efflux was triphasic, with half-times of 0.05-0.2 s, 1-5 s and 100-400 s for the first, second and third phases, respectively. This very fast first phase is certainly due to calcium efflux via the calcium-release channel of HSR vesicles. Both ruthenium red and neomycin inhibited the first phase of the calcium-independent calcium efflux and the first phase of the calcium-, AMP- or caffeine-induced calcium efflux completely, whilst the second phase was fully inhibited by ruthenium red only and partially inhibited by neomycin at high concentrations, indicating that the second phase of calcium release also occurs via the calcium-release channel. Various models for calcium efflux through the release channel have been tested by simulation. Activation and inhibition of the channel-mediated calcium efflux from HSR cannot be explained by two states of the calcium-release channel (open or closed), but requires the existence of at least three states. A channel with one open state and two closed states, resulting in a rapid inactivation, is the most simple model compatible with the experimental data. According to this model, activation is assumed to reduce inactivation of the channel, whilst inhibition assumes an acceleration of channel inactivation. This mechanism most likely applies to neomycin. An additional open-blocked state has to be assumed for inhibition by ruthenium red.
Splenic rupture presenting as primary malignant lymphoma of the spleen is a rare event. We report such an occurrence in a young man who had a primary B-cell immunoblastic lymphoma of the spleen and was found to be HIV-positive. We suggest that serologic tests for HIV should be performed in unusual cases of malignant lymphoma.
Activation and inhibition of the calcium release channel of rabbit skeletal muscle heavy sarcoplasmic reticulum (HSR) was investigated by various methods. The calcium release channel is activated by binding of calcium in the micromolar range and by binding of adenine nucleotides in the millimolar range. Ruthenium red and neomycin are potent inhibitors of the channel at nanomolar to micromolar concentrations. Dantrolene inhibits the rate of caffeine-induced calcium release. Several models of the calcium release channel were considered to explain the three-phasic calcium release from HSR vesicles. Simulation of calcium efflux data according to various models suggest that the calcium release channel has at least three states. The experimental results can be explained by assuming one open and two closed states of the calcium release channel, but not by assuming one open and one closed state.
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We compared the use of pediatric ambulatory medical care of 640 children who switched from a traditional Blue Cross plan to more comprehensive independent practice association plans with that of matched patients who remained with Blue Cross in one large, suburban pediatric practice in Rochester, NY. A quasi-experimental, retrospective cohort design was used. Use of pediatric ambulatory medical care by patients in the independent practice association plan and control patients was determined by medical chart review for 1 year before and 1 year after each patient's switch. During the baseline year, patients who would join the independent practice association plan already had 19% more acute-illness visits than control patients. During the second year, patients in the independent practice association plan averaged 42% more acute-illness visits, 22% more well child-care visits, 93% more chronic-illness visits, 27% more after-hours visits, 53% more weekend visits, 185% more laboratory studies, and 70% more referrals. The shift toward independent practice association plans in this open-market setting increased use of ambulatory medical care for pediatric patients.
Data were analyzed for 11,553 California offenders who in 1980 were convicted of assault, robbery, burglary, theft, forgery, or drug crimes. Whether an offender was given probation or sentenced to prison for such crimes could be predicted with about 80 percent accuracy from a combination of variables that described defendant and crime characteristics and criminal justice processing. The addition of race to the prediction equation for a given crime type did not improve the accuracy of the prediction. In addition, there was no evidence that other factors related to imprisonment (for example, number of conviction counts, going to trial) masked a relation between race and imprisonment. Race also was not related to the length of prison term imposed.
It is well known that clinical symptoms of deep venous thrombosis of the leg are not reliable. We studied the diagnostic value of compression sonography in the diagnosis of venous thrombosis of the lower extremity. Ultrasound examination was performed in patients in the supine position. The venous segments were evaluated almost exclusively with transversal scanning. In the thigh lacking compressibility of the venous lumen was the only criterion for thrombosis. In the calf, unobstructed veins can usually not be seen in the patient supine. In thrombosis however the vessel is dilated by the clot and appears as sonolucent incompressible channel. 178 patients were examined comparatively by venography and ultrasound (226 one extremity phlebogramms). Phlebography demonstrated 113 thromboses which could be demonstrated by ultrasound with a sensitivity of 95% and a specificity of 100%. In 92% the extension of thrombosis was estimated accurately. Thigh vein thrombosis was detected with a sensitivity of 97% and a specificity of 99%. Occlusion or patency of the common femoral vein was seen correctly in each case. Ultrasonic diagnosis of the superficial femoral vein thrombosis had a sensitivity of 97%, that of the popliteal vein of 98% and a specificity of 100% in both. Venous occlusion confined to the calf was detected with a sensitivity of 89% and a specificity of 99%. We conclude that compression sonography is a highly accurate diagnostic procedure for the diagnosis of deep venous thrombosis of the thigh as well as the calf. It should be the first choice of imaging method in the diagnosis of venous thrombosis of the leg.
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The increasing frequency and severity of urban violence and vehicular injuries have brought with them a rise in the number of complex vascular injuries. To examine the cause, incidence, management, and outcome of this problem, we created a vascular trauma registry which includes all such cases treated at a Level I metropolitan trauma center over the past nine years. This constitutes a summary report of that registry. During the period 1979-1988, 411 patients (355 men, 56 women) with 478 vascular injuries were treated. There were 18 deaths (4%). Primary diagnosis was grouped by anatomic region: (1) head and neck vessels, 62 (15%); (2) thoracic, 39 (10%); (3) abdominal and pelvic, 63 (15%); (4) upper extremity, 161 (39%); and (5) lower extremity, 86 (21%). Surgery was required in 241 cases (60%). Operative techniques consisted of ligation or resection in 26 (12%) and direct repair in 212 (88%). Associated procedures included: (1) laparotomy (n = 83); (2) craniotomy (n = 4); (3) thoracotomy (n = 49); (4) orthopedic procedures (n = 118); and (5) peripheral neurological repair (n = 70). Mechanisms of injury were: (1) gunshot wounds (32%); (2) stab wounds (45%); (3) motor vehicle accidents (18%); (4) fall (3%); and (5) other mechanisms (2%). We conclude: (1) vascular injuries were found frequently in the severely injured patient; (2) multiple vascular repairs were required in a significant proportion of these patients; and (3) outcome is dependent more upon associated trauma than on the vascular injuries themselves.
Two cases of malignant non-Hodgkin lymphoma of the retina and choroid with cerebral involvement are reported. In both cases, early infiltrates appear to have originated in the capillary layer of the choroid. Subsequently, Bruch's membrane was penetrated and tumorous infiltrates were found beneath the retinal pigment epithelium. The resulting reactions created a distinctive ophthalmoscopic picture, for which the term "leopardskin pattern" was coined. It may be helpful in early diagnosis, which with suitable therapy can prolong life.
One O6-methylguanine (O6-meG) was introduced into each BamHI site of lambda-phage DNA as a substrate for the determination of the DNA repair protein O6-alkylguanine-DNA-alkyltransferase. A new assay using as the detection group 32P-labeled phosphate introduced at the 3' position of the modified nucleoside by incorporation of 32P-labeled TTP in the 3'-neighboring position proved highly sensitive: 10(-16) mol of the DNA lesion was still easily detectable. This DNA, which has greater than 1000 bp represents a good model for cellular DNA and was used as a substrate to measure the individual repair capacities for O6-meG in human lymphocytes of 20 healthy male and female donors. There were great inter-individual variations in the activity of this repair protein in man. The influences of age, sex or smoking behavior on the repair capacity of O6-meG were negligible.
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exo mutants of Rhizobium meliloti SU47, which fail to secrete acidic extracellular polysaccharide (EPS), induce Fix- nodules on alfalfa. However, mutants of R. meliloti Rm41 carrying the same exo lesions induce normal Fix+ nodules. We show that such induction is due to a gene from strain Rm41, which we call lpsZ+, that is missing in strain SU47. lpsZ+ does not restore EPS production but instead alters the composition and structure of lipopolysaccharide. In both SU47 and Rm41, either lpsZ+ or exo+ is sufficient for normal nodulation. This suggests that in R. meliloti EPS and lipopolysaccharide can perform the same function in nodule development.
The importance of the decline in blood glucose concentration on lipolysis and the lipolytic effect of epinephrine was evaluated during short-term fasting. Lipolytic rates were determined by infusing [2H5]glycerol and [1-13C]palmitic acid. Five volunteers were studied after 12 h of fasting before and during epinephrine infusion and after 84 h of fasting, before and during glucose infusion when plasma glucose was restored to postabsorptive values, and during glucose plus epinephrine infusion. In another protocol, five volunteers were given glucose intravenously throughout fasting to maintain plasma glucose at postabsorptive levels and isotopic studies were performed after 12 and 84 h of fasting before and during epinephrine infusion. Glucose infusion after 84 h of fasting restored glucose and insulin concentrations and lipolytic rates toward 12-h fasting values. When euglycemia was maintained throughout fasting, plasma insulin still declined (P less than 0.05) and lipolytic rates still increased (P less than 0.05). Despite similar glucose concentrations, the lipolytic response to epinephrine infusion was greater after 84 h than after 12 h of fasting in both protocols (P less than 0.05). These studies demonstrate that the decline in plasma glucose contributes to, but is not required for, the increase in lipolysis during fasting. The increase in epinephrine-stimulated lipolysis that occurs during fasting is not dependent on a decrease in plasma glucose concentration.