Examination of the effects of hemodynamic and pharmacologic interventions on coronary collateral flow in a patient during cardiac catheterization

The vasomotor response of native human collateral vessels to pharmacologic or hemodynamic vasodilatory stimuli is not well known. We describe a case where retrograde collateral flow velocity was measured both at baseline and following selected hemodynamic and pharmacologic interventions. This index case represents the first in a series of potential human physiologic studies designed to address questions pertaining to control of collateral blood supply in humans. © 1993 Wiley-Liss, Inc.     

Cardiovascular responses to various autonomic tests in males and females

The results of cardiovascular autonomic reflex tests on 224 healthy, randomly selected subjects were analysed to study possible sex differences in the autonomic responses. The heart rate response to the Valsalva manoeuvre (Valsalva ratio) was greater in females over 50 years than in males of the same age (1.58 ± 0.34 vs. 1.44 ± 0.30,p < 0.05). The heart rate response to deep breathing (E/I ratio) was higher in females under 50 years than in males under 50 years (1.37 ± 0.17 vs. 1.34 ± 0.18,p < 0.001). The diastolic blood pressure response to isometric handgrip was higher in males under 50 years than in females of the same age (p < 0.05). Although there were sex differences in the magnitude of the responses, the effect of age was similar in males and females and accelerated attenuation of the autonomic responses could not be demonstrated with increasing age. It can be concluded that significant sex differences exist in cardiovascular autonomic responses. The implication of such differences need consideration.     

Role of intracortical mechanisms in the late part of the silent period to transcranial stimulation of the human motor cortex

Transcranial magnetic stimulation (TMS) and transcranial electrical stimulation (TES) of the human motor cortex produce a silent period (SP) following motor evoked potentials (MEPs). The early part of the SP can be explained by decreased alpha motor neuron excitability, whereas the late part is presumably due to suprasegmental mechanisms. In order to determine the level of the suprasegmental contribution to the generation of SPs, we recorded excitatory and inhibitory responses to TMS, TES, and percutaneous electrical brainstem stimulation (PBS) in the voluntarily activated first dorsal interosseous muscle of the hand. Stimulus intensities were set so that PBS and TES induced MEPs with areas equal to or larger than those of MEPs obtained with TMS. This procedure revealed that SPs were 49% and 83% shorter with TES and PBS, respectively, than with TMS. As TMS is more effective than TES or PBS in activating cortical interneurons, these findings support the idea that a significant component of the SP arises from intracortical mechanisms.     

Large granular lymphocyte expansions in patients with Felty's syndrome: analysis using anti-T cell receptor V beta-specific monoclonal antibodies.

Felty's syndrome (FS), the association of rheumatoid arthritis (RA) and idiopathic neutropenia, remains an unexplained phenomenon. HLA-DR4 is found in over 90% of cases. Patients with FS may have a T cell lymphocytosis of CD3+CD8+CD57+ large granular lymphocytes (LGL syndrome). In this study of 47 patients with FS, 19% had clear evidence for LGL expansions, while in total 42% had variable evidence for the LGL syndrome using currently available techniques. Of these T cell expansions, 76% were clonal, as demonstrated by Southern blotting and analysis with T cell receptor (TCR) beta chain constant region probes. This technique may fail to detect clonal populations in some patients. Cytofluorographic analysis using antibodies specific for TCR V beta chains identified patients with clonal LGL expansions with results comparable to those obtained with Southern blotting. No evidence for shared V beta usage among expansions from different patients was seen. The role of LGL in RA and FS is currently unclear, but this technique offers a practical and accessible means of identifying patients with LGL expansions, as a starting point for further investigation.     

Dorsal fracture of the hamate: distinctive radiographic appearance

Six patients who injured their wrists had radiographs documenting a dorsal, 5- to 10-mm oblong fragment of bone immediately proximal to the base of the fourth and/or fifth metacarpal bones. The fragment was seen on the pronation oblique and/or lateral projections, but not on the posteroanterior projection. The radiographic appearance of the fragment was remarkably similar in all cases. In the one patient in which it was performed, pluridirectional tomography demonstrated that the fragment originated from the dorsal surface of the hamate. Five of the six patients also had associated posterior dislocation of the fourth and/or fifth metacarpals. We conclude that this fragment represents a coronal fracture through the body of the hamate resulting from posterior dislocation or subluxation of the fourth and/or fifth metacarpal.     

Retrospective comparison of taping and ankle stabilizers in preventing ankle injuries

The effectiveness of taping and the effectiveness of wearing a laced stabilizer in preventing ankle injuries and reinjuries over six seasons of collegiate football practices and games were assessed retrospectively. For 1 1/2 years the players all had taped ankles, and for the remaining 4 1/2 years the players chose their type of ankle support. Over the entire period, the players chose high-top or low-top shoes as preferred. During 51,931 exposures to injury (46,789 practice-exposures and 5,142 game-exposures), the 297 players sustained 224 ankle injuries and 24 reinjuries. Tape was worn during 38,658 exposures to injury (233 players), stabilizers during 13,273 exposures (127 players). Tape had been worn when 159 of the injuries and 23 of the reinjuries occurred; a stabilizer had been worn when 37 of the injuries (P = 0.003) and one of the reinjuries occurred. The combination allowing the fewest injuries overall was low-top shoes and laced ankle stabilizers.     

Hormonal effects of high dose medroxyprogesterone acetate treatment in males with renal or prostatic adenocarcinoma

In 18 patients, 12 with renal and 6 with prostatic carcinoma, the gonadal, pituitary and adrenal functions were studied by measurements of steroid hormones and gonadotrophins, before and after six weeks treatment with medroxyprogesterone acetate (MPA), injected intramuscularly 500 mg per day for 5 days each week. The testosterone-oestradiol-binding globulin (TeBg) was measured and the amount of albumin and TeBg bound and unbound testosterone was calculated. Treatment with high doses of MPA caused a profound decrease in serum concentrations of testosterone, dehydroepiandrosterone sulphate (DHEAS), cortisol and TeBg. There were significant decreases in serum concentrations of luteinizing hormone (LH), follicle stimulating hormone (FSH) and oestradiol-17 beta. The serum concentration of prolactin was significantly elevated. The protein unbound testosterone fraction was lowered by MPA treatment but less than total testosterone. In conclusion, MPA therapy in high dose alters the gonadal, pituitary and adrenal functions suppressing serum concentrations of androgens, gonadotrophins, cortisol and TeBg but elevating prolactin concentration.     

Blood and plasma donations among a cohort of intravenous drug users

We evaluated the blood and plasma donation histories of a cohort of 2921 intravenous drug users in Baltimore, Md, and correlated these histories with their human immunodeficiency virus (HIV) serologic status, numbers of CD4 lymphocytes in the peripheral blood, and stigmata of intravenous drug use (scarred veins). Of the 793 intravenous drug users (27.1%) who had donated blood or plasma, 652 (82.2%) donated after they had started using intravenous drugs. Most subjects donated at commercial plasma centers, where they were paid $10 to $15 per donation. Although the HIV-1 seroprevalence of the entire cohort was 24.1%, the HIV-1 seroprevalence among those reporting plasma or blood donations declined progressively with time, from 17.1% in those who last donated in 1985 to 3.6% in those who last donated in 1988-1989. Many of the 437 intravenous drug users who had donated plasma or blood since 1985, when screening for HIV-1 was initiated, had not been notified and counseled about their HIV test results. Current programs to exclude individuals with a history of intravenous drug use from the plasma donor pool should be reevaluated and improved.     

Stimulus-secretion coupling of arginine-induced insulin release. Resistance of arginine- and ornithine-stimulated glucagon and insulin release to D,L-alpha-difluoromethylornithine

In the isolated perfused rat pancreas, D,L-difluoromethylornithine, tested at a concentration of 3 mmol/L, failed to affect the release of glucagon and insulin caused, over 15 min stimulation, by either L-arginine or L-ornithine (2.0, 5.0 or 10.0 mmol/L) in the presence of either 3.3 or 5.6 mmol/L D-glucose. The inhibition of ornithine decarboxylase also failed to affect the release of glucagon provoked by either L-leucine (2 or 3 mmol/L) or L-glutamine (2 mmol/L) and the secretion of insulin stimulated by a rise in glucose concentration from 5.6 to 10.6 mmol/L. These data are interpreted to suggest that the rapid generation of polyamines from either L-arginine or L-ornithine does not play any significant role in the immediate glucagonotropic and insulinotropic action of these cationic amino acids.     

Heparin-coated catheters and heparin-induced thrombocytopenia

Ten patients with heparin-coated pulmonary artery catheters had heparin-induced thrombocytopenia, which persisted after all other sources of heparin were discontinued. The thrombocytopenia occurred in approximately 0.4% of the patients receiving heparin-coated catheters and remitted when the catheters were removed. The platelet counts averaged 59,000/mm3 at the time of the diagnosis and recovered to an average of 143,000/mm3 by 3 days (range 2 to 4 days) after removal of the heparin-coated catheters. One patient required a second catheter 31 days after the first catheter had been removed. When the second heparin-coated catheter was inserted, the platelet count decreased from 307,000/mm3 to 102,000/mm3 in 4 days. Segments of heparin-coated pulmonary artery catheters were placed in platelet-rich plasma and incubated with serum from patients with known heparin-associated antiplatelet antibodies or with serum from volunteers with no exposure to heparin. The heparin-coated catheters induced platelet aggregation in all samples containing serum from patients with heparin-induced thrombocytopenia. However, platelet aggregation did not occur when the catheters were incubated with the serum of the volunteers. Non-heparin-coated catheters failed to produce platelet aggregation when incubated with either sera. The high mortality and morbidity rates associated with heparin-induced thrombocytopenia mandate that afflicted patients receive no more heparin, at least until the heparin-associated antiplatelet antibodies are no longer detectable. Patients with heparin-coated catheters who have thrombocytopenia should be tested for the presence of heparin-associated antiplatelet antibodies. If heparin-induced thrombocytopenia is confirmed, the catheters must be removed if the thrombocytopenia is to be reversed and complication avoided.