Different activities and footwear influence exposure to host-seeking nymphs of Ixodes scapularis and Amblyomma americanum (Acari: Ixodidae)

The relative potential for a person accidentally acquiring host-seeking nymphs of the blacklegged tick, Ixodes scapularis Say, and lone star tick, Amblyomma americanum (L.), while wearing either of two types of footwear, walking, crawling on hands and knees, and sitting on large fallen logs in deciduous woods, was evaluated. Although flag samples indicated substantial populations of I. scapularis nymphs and low to moderate numbers of A. americanum at the study sites, relatively few I. scapularis and fewer still A. americanum nymphs were acquired during 30-s and 5-min walks. Significantly fewer I. scapularis were picked up when boots were, worn with ankles taped (an anti-tick precaution) than when sneakers were worn with socks exposed during 5-min walks, but when thus attired, there was no significant difference between the number of nymphs acquired during 30-s walks. Nymphs of I. scapularis did not appear to accumulate incrementally on footwear or clothing during walks when boots were worn and ankles taped. Crawling for 30 s (approximately 3 m distance) yielded significantly more I. scapularis nymphs than walking for 30 s. During crawling, I. scapularis nymphs were picked up on 58% of the 30-s samples. Most ticks picked up during crawls were on pant legs. When a flannel flag cloth (0.5 by 0.5 m) was appressed to the upper surface of logs suitable to be sat upon by tired hikers, I. scapularis nymphs were found on 87% of the logs and in 36% of the samples. These data indicate that the potential for contact with host-seeking nymphs of I. scapularis occurring at these densities is greatly elevated by engaging in activities that involve contact with fallen logs and close contact of hands and knees with leaf litter.     

Endogene Natriuretische und Ouabain-ähnliche Faktoren

Summary The existence of an endogenous natriuretic hormone and ouabain-like factors (OLF) has been postulated for many years. This postulate was based on our original observation that a small M.W. fraction in the serum after acute expansion of the extracellular fluid volume (ECFV) not only exhibited natriuretic activity but also inhibited the Na-K-ATPase enzyme in vitro similar to ouabain. Since then, numerous studies confirmed the presence of OLFs in serum, urine, cerebrospinal fluid, and various organs including the heart and hypothalamus. Some of these OLFs are well-known endogenous compounds, such as free unsaturated fatty acids, which inhibit in vitro transmembranous sodium transport, Na-K-ATPase and³H-ouabain binding to its membrane receptor or crossreact with digoxin antibodies. Chemically yet undefined OLFs of potentially hypothalamic origin were detected in various models of experimental and clinical hypertension and are suggested to play a pathophysiological role especially in salt- and volume-dependent forms of hypertension. Our results show that OLFs isolated from the urine of salt-loaded healthy subjects strongly enhance basal and vasopressin-stimulated release of calcium in vascular smooth muscle cells and platelets similar to the effects we had observed with endothelin. This urine fraction also exhibits natriuretic activity which increases in parallel with sodium intake. Further chromatographic separation and amino acid analysis confirmed the peptidic nature (M.W.<1000) of the natriuretic factor(s). However, the two biological activities, namely natriuretic and ouabain-like activities, reside in distinct and chemically different compounds. In face of the previous discovery of the atrial natriuretic peptides (ANP) it is of special interest that very recent observations strongly suggest a natriuretic factor of non-cardiac origin to play an important role in the natriuresis that follows ECFV expansion. In addition, numerous experimental data point to an interaction between the ANP and OLF systems. They should stimulate once again the final identification of these yet unknown endogenous natriuretic and ouabain-like factors.

Die in dieser übersicht zitierten eigenen Untersuchungen wurden von der Deutschen Forschungsgemeinschaft, Bonn, dem Ministerium für Wissenschaft und Forschung des Landes Nordrhein-Westfalen (FA-2914, FA-8871, IVA6-402-046-87), Düsseldorf, und der Konrad-Adenauer-Stiftung, Bonn, unterstützt     

Modulation of a subthreshold calcium current by the neuropeptide FMRFamide in Aplysia neuron R15

1. The effect of the endogenous neuropeptide FMRFamide (Phe-Met-Arg-Phe-amide) on the Aplysia bursting pacemaker neuron R15 was studied. Brief local applications of FMRFamide, both on R15 somata in situ, and on R15 somata that were isolated and maintained in primary cell culture, cause a hyperpolarization of the membrane potential and a suppression of spontaneous bursting or beating pacemaker activity. 2. Two-electrode voltage-clamp experiments revealed that FMRFamide decreases the amplitude of an inward current, which activates with depolarization starting at a membrane potential less depolarized than the threshold for action potentials. Previous studies have established that this subthreshold inward current is carried by calcium and is essential for the generation of bursting pacemaker activity in Aplysia neurons. The effect of FMRFamide on the subthreshold inward current of R15 is blocked by divalent cation calcium channel blockers, such as cobalt and manganese, and is unaffected by changing the external concentration of potassium or chloride ions, or addition of blockers of the calcium-activated potassium current, such as external tetraethylammonium or internal EGTA. 3. The subthreshold calcium current of R15 is also decreased by dopamine and by an unidentified synaptic neurotransmitter. These substances mimic and occlude the action of FMRFamide on the subthreshold calcium current, suggesting that all three transmitters converge to affect the same population of calcium channels in neuron R15. 4. The subthreshold calcium current is enhanced by neurotransmitters that elevate cyclic AMP in R15, including serotonin, and the Aplysia neuropeptide egg-laying hormone (ELH). Likewise, the effect of FMRFamide on the subthreshold calcium current is enhanced by serotonin, ELH, and a cyclic AMP analog, suggesting that FMRFamide and cyclic AMP have antagonistic actions on the same population of calcium channels in neuron R15. 5. We conclude that the suppression of spontaneous bursting or beating pacemaker activity in neuron R15 by FMRFamide is due to a decrease in the subthreshold calcium current. The subthreshold calcium current in R15 is a common target for modulation by many different transmitters, acting via several distinct molecular mechanisms.     

Detection of Borrelia burgdorferi sensu lato in lesional skin of patients with erythema migrans and acrodermatitis chronica atrophicans by ospA-specific PCR.

The aim of this study was to develop a sensitive and specific PCR for the detection of Borrelia burgdorferi DNA. The plasmid-located gene coding for the outer surface protein A (OspA [31-kDa protein]) was used as a target. Nucleotide sequence information from different B. burgdorferi ospA genotypes was used to design primers homologous to different genotypes. The sensitivity of the nested PCR differed from 1 fg to 1 pg of borrelial DNA, depending on the strain analyzed. No cross-reactions with DNA from spirochetes other than B. burgdorferi or with human DNA were observed. A total of 22 skin biopsy samples from patients with erythema migrans (EM [n = 10]) or acrodermatitis chronica atrophicans (ACA [n = 12]) were examined for the presence of B. burgdorferi by nested PCR. Of 22 biopsies, 80% from EM patients and 92% from ACA patients were positive by PCR amplification. By comparison, 50% of the EM patients had elevated B. burgdorferi-specific immunoglobulin M (IgM) and/or IgG antibody levels as tested by enzyme-linked immunosorbent assay (ELISA) using purified B. burgdorferi flagella as antigen. A total of 33% of ACA patients had elevated IgM titers, and all had high IgG titers in their sera. Only 30% of specimens from patients with EM and none from patients with ACA were positive by culture. All culture-positive specimens were also positive by PCR. Thus, the sensitivities of the PCR were 80 and 92%, respectively, for patients with EM and ACA on the basis of the clinical and histopathological diagnoses of Lyme disease. From these results, we conclude that PCR is a suitable method to detect B. burdorferi sensu lato DNA in skin biopsy samples and could be applied as an additional diagnostic tool.     

Focal pulmonary edema. Correlation with perfusion lung scan

Pulmonary embolism is diagnosed by a mismatched perfusion-ventilation lung scan. The probability is increased further when there is an associated "hot spot" in the perfusion study caused by focal pulmonary edema.     

Maintenance ECT: A Survey of Practice (1986)

A questionnaire on the use of maintenance or continuation ECT was mailed to 173 practitioners of ECT. Of 86 respondents, 51 reported they used maintenance therapy, and 35 did not. Users came from 24 states, with five states accounting for more than half. Of practitioners giving maintenance ECT, each treated a median of three patients annually between 1981 through 1984, with a range from zero to "thousands." Frequency of treatments is determined empirically, with most treatments given monthly. Memory impairment is the most commonly cited risk. Depression is the diagnosis in 90% of the patients, with schizoaffective, schizophrenic, and manic patients equally comprising the remainder of the patients. The longest series reported for any one patient is 2,400 treatments.     

Failure of misonidazole-sensitized radiotherapy to impact upon outcome among stage III-IV squamous cancers of the head and neck

As part of the RTOG research effort in the treatment of advanced, inoperable squamous cancer of the head and neck region, the hypoxic cell sensitizer, misonidazole, was selected for investigation as an adjuvant to definitive irradiation. Based upon a pilot experience (78-02) showing a 67% complete response rate among 36 AJC Stage III-IV patients receiving full-dose irradiation and 6 weekly p.o. doses of misonidazole, a phase III trial was carried out from '79-'83. Three hundred and six patients were entered, 42% of whom had oropharyngeal primaries and with 78% of all cases representing T3 or T4 (inoperable) lesions. Only 16% of the entire series presented with N0 necks. Fractionation was altered among the misonidazole-receiving patients, in contrast to "standard" 5 treatments per week among "control" patients, such that 2 separate treatments were given on each day of p.o. misonidazole administration (2.0 gm/m2/wk X 6 doses, 2.5 Gy in a.m., 2.1 Gy in p.m.). Total tumor doses were identical among the two treatment arms except that a limitation of 40.0 Gy to spinal cord was specified for sensitized radiotherapy vs. 45.0 Gy for "control" patients. Primary tumor clearance was observed to be 55-60%, with minor variations according to tumor stage and site. The local regional control rate among radiotherapy-alone patients was 26% at 2 years compared to 22% (2 years) within the misonidazole-receiving group. Analysis of survival revealed no advantage to the sensitized patients, with 55 +/- 2% surviving 1 year and 22 +/- 1% living 3 years following treatment in both treatment categories. Distant metastases as first site of failure (12-13%) and the local failure among initial complete responders (46%) showed no advantage to the misonidazole group. Although a misonidazole dosage of 2.0 gm/m2/wk X 6 (12 gm/m2 total) is well tolerated, no clinical benefit was demonstrated in this randomized trial. Other nitroimidazole analogs (e.g. SR-2508) are now being investigated.     

"Clear cell" atypical fibroxanthoma

An 87-year-old man with extensive solar damage presented with a 2-month history of a dome-shaped, crusted lesion on the dorsum of the left hand. Microscopically, the tumor consisted of fascicles of spindle cells with bizarre nuclei and clear, vacuolated cytoplasm. Histochemical, immunohistochemical, and ultrastructural features supported the diagnosis of atypical fibroxanthoma. There was no evidence of metastatic disease. The lesion was completely excised, and there has been no recurrence in 3 months of observation. This unusual "clear cell" variant of atypical fibroxanthoma must be distinguished from other clear cell tumors, such as metastatic renal cell carcinoma, clear cell eccrine carcinoma, and clear cell sarcoma (malignant melanoma) of soft parts. Although atypical fibroxanthoma is usually cured by complete surgical excision, metastases have been reported.     

Adult-onset autosomal dominant limb-girdle muscular dystrophy

We describe a kindred with a rare autosomal dominant myopathy limited to the limb-girdle muscles, beginning insidiously any time from the late second through the sixth decades and followed by slow progression. Pelvifemoral precedes scapulohumeral weakness, and proximal appendicular involvement antedates limited distal paresis. Expressivity varies and includes an asymptomatic myopathy (preclinical or subclinical) and a nonmanifesting carrier state that extends well into the eighth decade. A variety of nonspecific changes are present in muscle on light, enzyme histochemical, and electron microscopic examination; of these changes, "rimmed" or autophagic vacuoles are the most characteristic. We identified one very similar previously reported genealogy. The similarities between the two unrelated families clearly establish this dystrophic process as a distinct genetic entity; their differences suggest genetic heterogeneity.     

The Yale algorithm. Special workshop--clinical

The assessment of causality in drug-event associations depends on the setting and purpose of such an assessment. Epidemiologists are primarily interested in population-based inferences about whether a given drug can cause a certain adverse drug reaction (ADR), and if so, how often it does so. Pharmaceutical industries and regulatory agencies are also concerned with population-based risks, but in addition must worry about individual cases. Clinicians are primarily interested in the individual, ie, whether a given drug did cause a certain adverse event in a particular patient. The authors describe an algorithm that provides specific, detailed criteria for ranking the probability that an observed untoward clinical manifestation was caused by a given drug. The criteria are subdivided into six axes of decision strategy with a built-in scoring system that ordinally ranks the probability of an adverse drug reaction as definite, probable, possible, or unlikely. To illustrate the use of the algorithm, the authors assess a reference case of pancreatitis occurring after administration of methyldopa.