Hereditary deficiency of the sixth component of complement in man. II. Studies of hemostasis.

Prompted by previous observations of defective blood clotting in rabbits deficient in the sixth component of complement (C6), an evaluation was made of the hemostatic functions of the homozygous proband of a newly recognized human kindred with hereditary C6 deficiency. This human subject, who had no clinical evidence of a bleeding disorder, exhibited a total lack of C6 by functional and immunoprecipitin assays of serum or plasma. Standard tests of hemostatic function were normal; however, when the whole blood clotting time was measured at 25 degrees C in plastic tubes, it was at the upper range of our normal values. In confirmation of this observation, prothrombin consumption, when performed at 37 degrees C in plastic tubes, was at the lower range of normal. Inulin and endotoxin, in concentrations shown to cause activation of human complement, had little or no effect on clotting times or prothrombin consumption of normal or C6-deficient human blood. These observations indicate that absence of C6 does not have a significant effect on hemostatic function in man. In the light of other investigations, the observed differences in clotting function between C6-deficient human blood and C6-deficient rabbit blood could be due to species differences governing the susceptibility of platelets to complement activation.

Symmetrical bone scan in a patient with acute hypercalcemia.

A previously healthy 49-year-old woman had symptoms of acute hypercalcemia that was not parathyroid-hormone mediated. Despite no clinical signs or symptoms of arthritis, a bone scan showed increased uptake in the juxtaarticular areas of the joints in the upper and lower extremities. The biopsy specimen of skeletal lesions noted on roentgenograms supported a diagnosis of multiple myeloma. Symmetrical lesions on bone scan in a patient with asymptomatic joints and acute hypercalcemia may be the first sign of an underlying hematologic malignant neoplasm.

Similarities and differences in the structure-activity relationships of capsaicin and resiniferatoxin analogues.

Structure-activity relationships in analogues of the irritant natural product capsaicin have previously been rationalized by subdivision of the molecule into three structural regions (A,B, and C). The hypothesis that resiniferatoxin (RTX), which is a high-potency ligand for the same receptor and which has superficial structural similarities with capsaicin, could be analogously subdivided has been investigated. The effects of making parallel changes in the two structural series have been studied in a cellular functional assay which is predictive of analgesic activity. Parallel structural changes in the two series lead to markedly different consequences on biological activity; the 3- and 4-position aryl substituents (corresponding to the capsaicin 'A-region') which are strictly required for activity in capsaicin analogues are not important in RTX analogues. The homovanillyl C-20 ester group in RTX (corresponding to the capsaicin 'B-region') is more potent than the corresponding amide, in contrast to the capsaicin analogues. Structural variations to the diterpene moiety suggest that the functionalized 5-membered diterpene ring of RTX is an important structural determinant for high potency. Modeling studies indicate that the 3D position of the alpha-hydroxy ketone moiety in the 5-membered ring is markedly different in the phorbol (inactive) analogues and RTX (active) series. This difference appears to be due to the influence of the strained ortho ester group in RTX, which acts as a local conformational constraint. The reduced activity of an analogue substituted in this region and the inactivity of a simplified analogue in which this unit is entirely removed support this conclusion.

The discovery of capsazepine, the first competitive antagonist of the sensory neuron excitants capsaicin and resiniferatoxin.

Capsaicin and resiniferatoxin are natural products which act specifically on a subset of primary afferent sensory neurons to open a novel cation-selective ion channel in the plasma membrane. These sensory neurons are involved in nociception, and so, these agents are targets for the design of a novel class of analgesics. Although synthetic agonists at the capsaicin receptor have been described previously, competitive antagonists at this receptor would be interesting and novel pharmacological agents. Structure-activity relationships for capsaicin agonists have previously been rationalized, by ourselves and others, by dividing the capsaicin molecule into three regions--the A (aromatic ring)-, B (amide bond)-, and C (hydrophobic side chain)-regions. In this study, the effects on biological activity of conformational constraint of the A-region with respect to the B-region are discussed. Conformational constraint was achieved by the introduction of saturated ring systems of different sizes. The resulting compounds provided agonists of comparable potency to unconstrained analogues as well as a moderately potent antagonist, capsazepine. This compound is the first competitive antagonist of capsaicin and resiniferatoxin to be described and is active in various systems, in vitro and in vivo. It has recently attracted considerable interest as a tool for dissecting the mechanisms by which capsaicin analogues evoke their effects. NMR spectroscopy and X-ray crystallography experiments, as well as molecular modeling techniques, were used to study the conformational behavior of a representative constrained agonist and antagonist. The conformation of the saturated ring contraint in the two cases was found to differ markedly, dramatically affecting the relative disposition of the A-ring and B-region pharmacophores. In agonist structures, the A- and B-regions were virtually coplanar in contrast to those in the antagonist, in which they were approximately orthogonal. A rationale for agonist and antagonist activity at the capsaicin receptor is proposed, based on the consideration of these conformational differences.

Listeria monocytogenes septic arthritis.

Listeria monocytogenes was isolated from both the blood and the synovial fluid of a diabetic patient with a septic arthritis involving the ankle.

Blood--its derivatives and its problems--factor VIII.

Unfortunately, all of the problems of the hemophiliac have not been solved by the availability of concentrated factor VIII products. Patients still are faced with the crippling effects of arthritis, problems with employment, problems with ignorance (both medical and lay), and an increased risk of premature death even in a sophisticated, treatment-oriented, community (Table 3). It can only be hoped that we can solve the problems of hepatitis transmission, availability, and economics so that concentrated forms of factor VIII can be made available to all patients with hemophilia. It seems appropriate to suggest that our severely affected patients should be placed on some prophylactic programs, since this would ease most of the long-term psychologic and physical disabilities common to this disease.

Outflow resistance of the Baerveldt glaucoma drainage implant and modifications for early postoperative intraocular pressure control.

PURPOSE: To determine outflow resistance of the Baerveldt glaucoma implant using different tube configurations. METHODS: Outflow resistance of 6 tube configurations (C1- C6) of Baerveldt implants was measured under conditions of constant pressure perfusion. Pressures ranged from 2 to 55 mm Hg. Venting slits were created using a 7-0 Vicryl, spatulated suture-needle. Seton tubes were occluded by threading a retrograde suture approximately 1.5 cm into the lumen. RESULTS: At pressures between 2 and 55 mm Hg, mean outflow resistance of the normally configured seton (ie, open tube; C1) was 0.41 (+/- 0.6) mm Hg/microL/min. Resistance was unchanged (mean 0.41 (+/- 0.4) mm Hg/microL/min) by the addition of 4 venting slits (C2) to the seton tube. Occlusion of the open seton tube with a 3-0 Supramid suture (C3) significantly increased (P < 0.001) mean outflow resistance to 14.99 (+/- 0.6) mm Hg/microL/min. Occlusion of the tube with a 4-0 Supramid suture (C4) significantly increased (P < 0.001) mean outflow resistance to 1.09 (+/- 0.5) mm Hg/microL/min. In implants where tubes were occluded with a 3-0 Supramid suture, the addition of venting slits (C5) significantly decreased (P = 0.038) mean outflow resistance to 8.98 (+/- 0.4) mm Hg/microL/min. In tubes occluded with a 4-0 Supramid suture, the addition of venting slits (C6) decreased mean outflow resistance to 0.98 (+/- 0.6) mm Hg/microL/min. CONCLUSIONS: Although these results cannot be directly correlated to the clinical setting, they do show that outflow resistance can be modified at the time of surgery by changing tube configuration of the Baerveldt glaucoma implant. Configuration C5 (3-0 Supramid with venting slits) closely approximates the outflow rate in the normal intraocular pressure range.

Locus of control and alcohol placebo effects on performance in a driving simulator.

Performance in a driving simulator was evaluated as a function of locus of control, perceived alcohol ingestion (no alcohol versus a no-alcohol placebo), and sex. Using a pretest-posttest design, an analysis of covariance was performed using the pretest performance on a driving simulator as the covariate. There were 10 men and 10 women in each of four groups. As predicted, the external-scoring placebo subjects made more posttest errors than did the internal-scoring placebo group or either of the no-alcohol control groups. This indicated that the external-scoring placebo subjects were more affected by what they expected to happen than their actual physiological state warranted. A difference was also found in which external-scoring women made more errors than did any other group. This was an unexpected finding which, being inconsistent with previous findings involving sex, warrants further research.

Locus of control and perceived alcohol ingestion in performance of a fine motor skill.

To investigate the influence of locus of control on a fine motor corrdination task where subjects had ingested or believed that they had ingested alcohol, 60 men who were enrolled in introductory psychology and scored in the upper or lower thirds of the population on Rotter's I-E Scale (30 external and 30 internal scorers) were randomly assigned to one of three treatment conditions: a control group (no alcohol expected/no alcohol received), an alcohol group (alcohol expected/alcohol received), and a placebo group (alcohol expected/no alcohol received). Pretest and posttest measures of performance on the Purdue Pegboard Test were obtained from all subjects. Subjects in the control groups were given three 6-oz. (177.4-ml) glasses of fruit punch over a 35-min. waiting period between pretest and posttest on the Purdue Pegboard. The alcohol groups drank a sufficient number of similar glasses (usually three) to produce a 0.1% measure on a breathalyzer before completing the posttest on the Purdue. Pegboard. The placebo groups were told that they were drinking an alcohol-based drink but were served three glasses of a nonalcoholic, rum-flavored fruit drink. These groups were also told that they measured 0.1% on a breathalyzer. Control groups, both internal and external scorers, showed essentially no change from pre- to posttest on the Purdue Pegboard. The alcohol groups, on the other hand, both internal and external scorers, showed a significant decrement in performance. The internal-placebo group did not differ from the two control groups and showed no decrement in performance.(ABSTRACT TRUNCATED AT 250 WORDS)

Technical note: A comparison of DNA collection methods in cattle and yaks.

A variety of biological materials are suitable for the analysis of bovine DNA. The objective of this study was to evaluate the ease of collection, storage, and cost as well as quality and quantity of DNA samples obtained from Bos taurus (European cattle) and Bos grunniens (yak) using 2 different sample types: whole blood sampling and nasal swabs. Hair follicle DNA samples from yaks were also analyzed. Deoxyribonucleic acid samples were collected from 1 herd of Black Angus yearling bulls (n = 166) and 1 herd of yaks (n = 24). A NanoDrop Bioanalyzer ND1000 was used to quantify DNA. To assess DNA purity, absorbance ratios were determined at wavelengths of 260 nm relative to 280 nm and 260 nm relative to 230 nm. Single nucleotide polymorphism genotyping was performed using a competitive allele-specific PCR (KASP) genotyping system and the call rates to 3 specific SNP were compared. Using a commercially available nonautomated ethanol DNA extraction technique, nasal swabs yielded a greater quantity of DNA than blood (P < 0.0001) and a greater quality DNA sample than blood (P < 0.0001). Blood and nasal swab performance in SNP genotyping assays were similar (P = 0.5). The greater expense of nasal swabs was offset by their ease of use: less time, skill, and equipment was needed to obtain a sample and the storage of samples was more convenient (room temperature). In yaks, accessing the coccygeal vein, which is relatively straightforward in cattle, was difficult. Nasal swabbing and hair follicle sampling in yaks was performed relatively easily. Yak hair follicles were a poor source of DNA. In conclusion, DNA collection using nasal swabs was more convenient and provided a greater quantity of DNA and better quality sample than blood collection in both Angus and yak. Notably, yak hair was a poor source of DNA, and yak blood was difficult to obtain.