Spleen reactivity during incremental ascent to altitude

The spleen contains a reservoir of red blood cells that are mobilized into circulation when under physiological stress. Despite the spleen having an established role in compensation to acute hypoxia, no previous work has assessed the role of the spleen during ascent to high altitude. Twelve participants completed 2 min of handgrip exercise at 30% of maximal voluntary contraction at 1,045, 3,440, and 4,240 m. In a subset of eight participants, an infusion of phenylephrine hydrochloride was administered at a dosage of 30 µg/l of predicted blood volume at each altitude. The spleen was imaged by ultrasound via a 2- to 5.5-MHz curvilinear probe. Spleen volume was calculated by the prolate ellipsoid formula. Finger capillary blood samples were taken to measure hematocrit. Spleen images and hematocrit were taken both before and at the end of both handgrip and phenylephrine infusion. No changes in resting spleen volume were observed between altitudes. At low altitude, the spleen contracted in response to handgrip [272.8 ml (SD 102.3) vs. 249.6 ml (SD 105.7), P = 0.009], leading to an increase in hematocrit (42.6% (SD 3.3) vs. 44.3% (SD 3.3), P = 0.023] but did not contract or increase hematocrit at the high-altitude locations. Infusion of phenylephrine led to spleen contraction at all altitudes, but only lead to an increase in hematocrit at low altitude. These data reveal that the human spleen may not contribute to acclimatization to chronic hypoxia, contrary to its response to acute sympathoexcitation. These results are explained by alterations in spleen reactivity to increased sympathetic activation at altitude. NEW & NOTEWORTHY The present study demonstrated that, despite the known role of the human spleen in increasing oxygen delivery to tissues during acute hypoxia scenarios, the spleen does not mobilize red blood cells during ascent to high altitude. Furthermore, the spleen's response to acute stressors at altitude depends on the nature of the stressor; the spleen's sensitivity to neurotransmitter is maintained, while its reflex response to stress is dampened.

Maternal cardioautonomic responses during and following exercise throughout pregnancy

Blood pressure regulation during pregnancy is poorly understood. Cardiovagal baroreflex gain (BRG) is an important contributor to blood pressure regulation through its influence on heart rate. Heart rate fluctuations occur in response to various physiological stimuli and can be measured using heart rate variability (HRV). It is unclear how these mechanisms operate during pregnancy, particularly with regard to exercise. We examined BRG and HRV prior to, during, and following prenatal exercise. Forty-three pregnant (n = 10 first trimester (TM1), n = 17 second trimester (TM2), n = 16 third trimester (TM3)) and 20 nonpregnant (NP) women underwent an incremental peak exercise test. Beat-by-beat blood pressure (photoplethysmography) and heart rate (lead II electrocardiogram) were measured throughout. BRG (the slope of the relationship between fluctuations in systolic blood pressure and the R-R interval) and HRV (root mean square of the successive differences; RMSSD) were assessed at rest, during steady-state exercise (EX), and during active recovery. BRG decreased with gestation and was lower in the TM3 group than in the NP group (17.9 ± 6.9 ms/mm Hg vs 24.8 ± 7.4 ms/mm Hg, p = 0.017). BRG was reduced during EX in all groups. Resting HRV (RMSSD) also decreased with gestation and was lower in the TM3 group than in the NP group (29 ± 17 ms vs 48 ± 20 ms, p < 0.001). RMSSD was blunted during EX in all groups compared with rest. During active recovery, RMSSD was further blunted compared with EX in the NP group but not during pregnancy (TM1, TM2, and TM3). Compared with the nonpregnant controls, the pregnant women had lower BRG and HRV at rest, but comparable cardioautonomic control during both exercise and active recovery following peak exercise.

Probable Phaeoacremonium parasiticum as a cause of cavitary native lung nodules after single lung transplantation

Lung nodules after lung transplantation most often represent infection or post-transplant lymphoproliferative disorder in the allograft. Conversely, native lung nodules in single lung transplant recipients are more likely to be bronchogenic carcinoma. We present a patient who developed native lung cavitary nodules. Although malignancy was anticipated, evaluation revealed probable Phaeoacremonium parasiticum infection. Phaeoacremonium parasiticum is a dematiaceous fungus first described as a cause of soft tissue infection in a renal transplant patient. Lung nodules have not been previously described and this is the first case, to our knowledge, of P. parasiticum identified after lung transplantation.

Madelung's deformity: quantitative radiographic comparison with normal wrists

Four measurements, ulnar tilt, lunate subsidence, lunate fossa angle and palmar carpal displacement, on wrist radiographs of 26 patients with Madelung's deformity and 48 normal subjects were compared. The range of measurements on wrists with Madelung's deformity was wider than on normal wrists, with severe deformities having very abnormal values. Some Madelung's patients had values that were within the normal range for each of the four measurements. Measurement of the lunate fossa angle demonstrated the least overlap between normal wrists and wrists of patients with Madelung's deformity with only two in the normal range. A lunate fossa angle over 29 degrees may help identify early Madelung's deformity.

An investigation into the 'carry over' effect of neurostimulation in the treatment of angina pectoris

Neurostimulation, by way of transcutaneous electrical nerve stimulation (TENS) and spinal cord stimulation, improves signs and symptoms of myocardial ischaemia, with evidence (from non-randomised studies) that this effect extends beyond the period of stimulation itself ('carry-over' effect). In this randomised controlled trial, 10 patients underwent baseline treadmill-exercise-testing (TET), followed by two further tests at fortnightly intervals. TENS was compared to placebo in a randomised fashion. TENS produced a significant increase in total exercise time (399.3 vs. 364.5 s, p < 0.05) and time to maximum ST depression (374 vs. 324 s, p = 0.01) without a significant difference in the maximum degree of ST depression (2.0 vs. 2.1 mm, p = NS). Rate-pressure product at peak exercise was not significantly different (197 vs. 193, p = NS). TENS produced a nonsignificant change in time to onset of angina (352 vs. 325 s, p = 0.07). Pre-treatment with TENS produces a significant improvement in exercise tolerance and measures of ischaemia but not significant improvement in symptoms.

Human cytokine responses to meso-endemic malaria on the Pacific Coast of Colombia

Studies of naturally-acquired immunity to malaria in endemic regions provide the potential for a greater understanding of the regulation of human immune responses to the malarial parasite. However, little is known about the acquisition of malaria-specific immunity in regions of unstable, meso-endemic or hypo-endemic transmission. Cytokine profiles - patterns in the expression of interleukin-4 (IL-4), interleukin-10, interleukin-12, interferon-gamma (IFN-gamma) and tumour necrosis factor-alpha (TNF-alpha) - were therefore studied during the natural acquisition of immunity to Plasmodium falciparum and P. vivax among individuals from Buenaventura, a meso-endemic region on the Pacific Coast of Colombia. In general, specific type-1 immune responses, characterized by IFN-gamma expression, were more likely to develop during P. falciparum infection, whereas pro-inflammatory cytokine profiles (with TNF-alpha expression) were observed more frequently among the P. vivax infections. Type-2 cytokine profiles, characterized by dominant IL-4 expression, were infrequent. Expression of IL-4 probably occurs primarily after prolonged exposure to parasites (which would, by definition, not be common in a meso-endemic region).

Validating a New Sham (Placebo) Acupuncture Device: Two Randomized Controlled Trials

Background

For clinical trials of acupuncture, it would be desirable to have a sham procedure that is indistinguishable from the real treatment, yet inactive. A sham needle has been designed which telescopes instead of penetrating the skin. The Park Sham Device involves an improved method of supporting the sham needle and requires validation.

Objective

To test whether the sham procedure using the new device is: 1. Indistinguishable from real needles, and 2. Inactive.

Design

Two subject and assessor-blind, randomized controlled trials. Study samples: Study 1: 58 patients included in a clinical trial of acupuncture for acute stroke. Study 2: 63 healthy, acupuncture naïve, adult volunteers. Intervention: Real or sham acupuncture using the Park Sham Device. Settings: 1. District general hospital, 2. University laboratory. Measurements: 1. The form of treatment that patients believed they had received 2. Experience of de-qi, as judged by three acupuncture experts.

Results

Study 1: No patient in either group believed s/he had been treated with the sham needle. Study 2: In 40 volunteers for whom experts achieved consensus, the relative risk of experiencing de-qi with real acupuncture to that with sham acupuncture was 15.38 (95% CI 2.26 to 104.86). The inter-rater reliability of all 13 experts, calculated from their judgements on 10 subjects selected by randomisation, was 0.52 (95% CI 0.19 to 0.61).

Conclusions

Results suggest that the procedure using the new Park Sham Device is both indistinguishable from real acupuncture and inactive. It is therefore a valid control for acupuncture trials. The findings also lend support to the existence of de-qi, a major concept underlying traditional Chinese acupuncture.

Effect of influenza A virus infection on nasopharyngeal colonization and otitis media induced by transparent or opaque phenotype variants of Streptococcus pneumoniae in the chinchilla model

Phase variation in the colonial opacity of Streptococcus pneumoniae has been implicated as a factor in bacterial adherence, colonization, and invasion in the pathogenesis of pneumococcal disease. Additionally, the synergistic effects of influenza A virus and S. pneumoniae in the development of otitis media (OM) have been reported. This study examined the ability of opaque or transparent S. pneumoniae from the same strain in combination with an antecedent influenza A virus infection to colonize the nasopharynx and invade the middle ear in the chinchilla model. Our data indicated that there was no significant difference in the level of nasopharyngeal colonization and induction of OM between the opaque and transparent variants unless there was a prior challenge with influenza A virus. Subsequent to influenza A virus infection, there was a significant difference between the variants in the ability to colonize and persist in the nasopharynx and middle ear. The concentrations of the opaque variant in nasopharyngeal-lavage samples and middle-ear fluid remained consistently higher than those of the transparent variant for 10 days postinoculation. Data from this study indicate that the effects of influenza A virus on the pathogenesis of experimental S. pneumoniae-induced OM differ depending on the opacity phenotype involved.

The effect of systemic blood pressure on cardio-vascular reflexes in elderly subjects

The evidence for impairment of cardiovascular reflexes by hypertension in elderly subjects is mixed. This study tested the hypothesis that baroreceptor- and non-baroreceptor-mediated responses in elderly subjects differed with hypertension. 54 elderly subjects were studied: 16 with combined hypertension (CT) (blood pressure 184 +/- 4/102 +/- 2 mmHg), 16 with isolated systolic hypertension (180 +/- 3/85 +/- 1 mmHg) and 22 normotensives (NT) (138 +/- 2/76 +/- 1 mmHg). All subjects performed isometric exercise with a handgrip dynamometer. Heart rate (HR), blood pressure and forearm vascular resistance (FVR) responses were then studied to 60 degrees head-up tilt and the cold face stimulus. Baseline FVR, and the response to isometric handgrip, were similar in all groups. Subjects with isolated systolic hypertension manifested greater increases in FVR with tilt (P<0.001), whilst the HR increment was greater in the NT group (P<0.001). Blood pressure changes with tilt were similar in the three groups. With the cold face stimulus (CFS) a rise in FVR of approximately 30% was seen in all groups and blood pressure rose modestly, with the largest increases being seen in the combined hypertensives. This study in elderly subjects indicates significant differences with hypertension in the response to tilt, with an impaired baroreceptor-cardiac reflex being compensated by an augmented baroreceptor-vascular response.

Evaluation of phase variation of nontypeable Haemophilus influenzae lipooligosaccharide during nasopharyngeal colonization and development of otitis media in the chinchilla model

Nontypeable Haemophilus influenzae (NTHI) has four loci, lic-1 to lic-3 and lgtC, that generate phase-variable lipooligosaccharide (LOS) structures. lic-1, which is required for the expression of phosphorylcholine (ChoP), is the best characterized and is associated with an enhanced ability of H. influenzae to persist within the nasopharynges of infant rats. Recent data indicate that LOS impacts various aspects of NTHI virulence in the chinchilla model of nasopharyngeal colonization and otitis media (OM). In this study the effects of ChoP expression and the sequences of lic-1 to lic-3 and lgtC of NTHI strain 2019 were evaluated in the chinchilla OM model. Nasopharyngeal colonization data showed that a switch from the ChoP(-) to the ChoP(+) phenotype was observed as early as day 3 after intranasal inoculation. Chinchillas colonized by strains with the ChoP(+) phenotype demonstrated a significantly higher level of NTHI 2019 per milliliter of nasal lavage fluid than chinchillas colonized with predominantly the ChoP(-) variant (P < 0.05). The concentration of cells with the ChoP(+) phenotype in the middle ear was 3 log units higher than that of cells with the ChoP(-) variant (P < 0.01). There was a statistically significant association between ChoP(+) expression in the nasal lavage and the development of OM with culture-positive middle ear fluids in this model. These data suggest that expression of the ChoP(+) phenotype promotes enhanced nasopharyngeal colonization and development of OM.

Wall stress and hypertension

The precise role that abnormal wall stress may play in the pathophysiology of hypertensive heart disease is not known. Hypertension is almost unique in that it ultimately affects all parts of the law of Laplace equation, i.e. intraventricular pressure changes and with the advent of left ventricular hypertrophy both internal radius and wall thickness alter. If heart failure supervenes the components of the equation change once more. This article will discuss the implications of abnormal wall stress at these various stages in hypertensive heart disease.

Evaluation of the virulence of a Streptococcus pneumoniae neuraminidase-deficient mutant in nasopharyngeal colonization and development of otitis media in the chinchilla model

Considerable evidence has implicated Streptococcus pneumoniae neuraminidase in the pathogenesis of otitis media (OM); however, its exact role has not been conclusively established. Recently, an S. pneumoniae neuraminidase-deficient mutant, DeltaNA1, has been constructed by insertion-duplication mutagenesis of the nanA gene of S. pneumoniae strain D39. The relative ability of DeltaNA1 and the D39 parent strain to colonize the nasopharynx and to induce OM subsequent to intranasal inoculation and to survive in the middle ear cleft after direct challenge of the middle ear were evaluated in the chinchilla model. Nasopharyngeal colonization data indicate a significant difference in the ability of the DeltaNA1 mutant to colonize as well as to persist in the nasopharynx. The neuraminidase-deficient mutant was eliminated from the nasopharynx 2 weeks earlier than the D39 parent strain. Both the parent and the mutant exhibited similar virulence levels and kinetics during the first week after direct inoculation of the middle ear. The DeltaNA1 neuraminidase-deficient mutant, however, was then completely eliminated from the middle ear by day 10 postchallenge, 11 days before the D39 parent strain. Data from this study indicate that products of the nanA gene have an impact on the ability of S. pneumoniae to colonize and persist in the nasopharynx as well as the middle ear.

Dental and skeletal findings on an ancient Egyptian mummy

The dentofacial structures of an ancient Egyptian mummy were radiographically evaluated from available computer tomographic scans. The cephalometric measurements obtained were compared to those available on ancient Egyptian Pharaohs as well as to modern cephalometric standards for adult males. The measurements on "Lady" Udja were closely related to both sets of cephalometric standards. The dental findings include: noticeable generalized attrition of the dentition, extracted lower first molar, and impacted maxillary third molars.

Percutaneous cholecystostomy is an effective treatment for high-risk patients with acute cholecystitis

We sought to determine the safety, efficacy, and outcome of percutaneous cholecystostomy (PC) in all patients undergoing the procedure at our institutions. We reviewed 53 consecutive cases of acute cholecystitis seen at our hospitals over 5.5 years in which PC was performed at the initial treatment. Follow-up was obtained by chart review and telephone questionnaire. Acute cholecystitis was the primary admitting diagnosis in 18 cases. In the remaining 35, cholecystitis developed during hospitalization. All patients were considered high surgical risks on the basis of the presence of comorbid conditions. The gallbladder was successfully catheterized under radiologic guidance in all patients and with no immediate procedure-related morbidity. Acute cholecystitis resolved in 44 of 53 patients (83%), whereas nine patients (17%) did not improve clinically after PC and died during the same hospitalization. A total of 33 (62%) eventually survived hospitalization. Elective cholecystectomy was done in 25 patients with no mortality. After cholecystectomy, three of these patients subsequently died of other causes, whereas 22 are alive. Eight patients did not undergo cholecystectomy because of underlying medical conditions or because they had acalculous cholecystitis. These patients remained free of biliary problems after removal of their cholecystostomy tube, but two have subsequently died of nonbiliary conditions. Percutaneous cholecystostomy is a safe, effective treatment for high-risk patients with acute cholecystitis. Cholecystostomy can be followed by elective cholecystectomy at a later time if the patient's condition permits or by expectant conservative management in patients who have had acalculous cholecystitis or have a very high mortality risk with surgery.

The spectrum of radial longitudinal deficiency: a modified classification

The records of 119 patients with 196 extremities with radial longitudinal deficiency seen between 1923 and 1996 were reviewed. We propose a global classification system that includes the spectrum of pathology affecting the radial side of the extremity, including deficiency of the radius, carpal abnormalities, and hypoplastic thumbs. Radial deficiency could be classified for 181 extremities of 104 patients using this classification system. Type N has a normal length radius and a normal carpus with thumb hypoplasia, type O has a normal length radius and radial side carpal abnormalities, type 1 has more than 2 mm shortening of the radius, type 2 has a hypoplastic radius, type 3 has a partial radius with absence of the distal physis, and type 4 has complete absence of the radius. All patients had thumb hypoplasia. Eighty-two percent of extremities with thumb hypoplasia but no deficiency of the radius that were available for carpal bone classification had carpal anomalies, including absence, hypoplasia, and coalitions. All the extremities with type 1 radial deficiency had carpal anomalies. Carpal abnormalities could not be determined for types 2, 3, and 4 deficiency because most had a prior centralization. Proximal radioulnar synostosis or congenital dislocation of the radial head was seen in 44% of extremities with type 1 radial deficiency. This classification includes carpal anomalies and thereby links isolated thumb hypoplasia and deficiency of the radius into one system.

Orthostatic blood pressure changes and arterial baroreflex sensitivity in elderly subjects

BACKGROUND

orthostatic hypotension in elderly people is often attributed to diminished afferent baroreflex sensitivity, but this has not been demonstrated. We examined the hypothesis that postural change in blood pressure is related to baroreflex sensitivity, independent of the confounding effect of baseline blood pressure.

METHODS

we studied 25 active, untreated elderly subjects free of postural symptoms (mean age 70 +/- 1 years): 16 with hypertension (clinic blood pressure 194 +/- 6/98 + 3 mmHg) and nine normotensive controls (clinic blood pressure 134 + 3/77 + 3 mmHg). We assessed baroreflex sensitivity from the heart rate and blood pressure responses to the Valsalva manoeuvre and a pressor and depressor stimulus (bolus phenylephrine injection or sodium nitroprusside infusion respectively). Subjects were then passively tilted to 60 degrees and maximum changes in systolic blood pressure, heart rate, forearm blood flow and forearm vascular resistance recorded.

RESULTS

maximum change in systolic blood pressure with head-up tilt was correlated with supine systolic blood pressure (r = 0.60, P = 0.001). Maximum change in systolic blood pressure with orthostasis was greater in the hypertensive subjects (45 +/- 4 mmHg versus 29 +/- 6, P = 0.04) and the heart rate increment was less (16 +/- 2 bpm versus 24 +/- 4, P = 0.02). The increase in forearm vascular resistance with tilt was similar in the two groups (47 +/- 11 versus 38 +/- 7 units, P = 0.52). All three methods of assessing baroreflex sensitivity showed a reduction in the hypertensive subjects (all P < or = 0.02). Lower values of baroreflex sensitivity were related to greater falls in systolic blood pressure with tilt, after adjustment for the baseline level of systolic blood pressure.

CONCLUSIONS

we found a relationship between baroreflex sensitivity and the systolic blood pressure fall with orthostasis, even after adjustment for prevailing systolic blood pressure. Despite equivalent changes in forearm vascular resistance with tilt, greater falls in systolic blood pressure were seen in hypertensive subjects than in normotensive controls, due in part to an inadequate baroreflex-mediated heart rate response. The postural fall in blood pressure often observed in elderly hypertensive subjects may be related to the reduced baroreflex sensitivity seen in this condition.

Local and systemic cytokine expression during experimental chronic Trypanosoma cruzi infection in a Cebus monkey model

Cebus apella is an acceptable model for chronic chagasic cardiomyopathy (CCC), since it is possible to experimentally induce cardiac lesions after 1 year of Trypanosoma cruzi infection. The T. cruzi Y strain, shown previously to produce CCC in C. apella monkeys, was used to experimentally infect 10 monkeys. Parasitological, serological and clinical parameters were monitored during a 19-month follow-up, and systemic cytokine responses were assessed sequentially in five monkeys selected according to the differential parasitemia pattern exhibited. Ten additional monkeys, infected with the same strain for 5, 10 and 12 years, were analysed cross-sectionally. Three monkeys/time point and one uninfected control animal were sacrificed for gross pathology, histology, presence of parasites, and local cytokine gene expression. Elevated expression of interleukin (IL)-4 was observed throughout the study in monkeys that had persistent, high parasitemias, whereas a high level of interferon (IFN)-gamma was seen in monkeys that controlled parasitemias soon after infection. Chronically infected monkeys expressed a nonpolarized, Th0-type response. Cardiac tissue collected from a monkey that succumbed to acute infection had elevated levels of proinflammatory cytokine [IL-1beta, IL-6, tumour necrosis factor-alpha] and interstitial cell adhesion molecule (ICAM)-1, platelet-derived growth factor (PDGF)-alpha, transforming growth factor (TGF)-beta and IL-10 transcripts. Cytokine production in cardiac tissue of chronically infected monkeys was also characterized by elevated expression of ICAM-1, PDGF-alpha and TGF-beta, which correlated with the detection of T. cruzi DNA by polymerase chain reaction.

Spinal cord stimulation significantly decreases the need for acute hospital admission for chest pain in patients with refractory angina pectoris

OBJECTIVE

To assess the impact of spinal cord stimulation (SCS) on the need for acute admissions for chest pain in patients with refractory angina pectoris.

DESIGN

Retrospective analysis of case records.

PATIENTS

19 consecutive patients implanted for SCS between 1987 and 1997. All had three vessel coronary disease, and all were in New York Heart Association functional group III/IV.

METHODS

Admission rates were calculated for three separate periods: (1) from initial presentation up until last revascularisation; (2) from last revascularisation until SCS implantation; (3) from SCS implantation until the study date. Post-revascularisation rates were then compared with post-SCS rates, without including admissions before revascularisation, as this would bias against revascularisation procedures.

RESULTS

Annual admission rate after revascularisation was 0.97/patient/year, compared with 0.27 after SCS (p = 0.02). Mean time in hospital/patient/year after revascularisation was 8.3 days v 2.5 days after SCS (p = 0.04). No unexplained new ECG changes were observed during follow up and patients presented with unstable angina and acute myocardial infarction in the usual way.

CONCLUSIONS

SCS is effective in preventing hospital admissions in patients with refractory angina, without masking serious ischaemic symptoms or leading to silent infarction.

Older subjects show no age-related decrease in cardiac baroreceptor sensitivity

OBJECTIVE

To examine the relationship between age, blood pressure and cardiac baroreceptor sensitivity derived from spectral analysis, the Valsalva manoeuvre and impulse response function.

METHODS

We studied 70 healthy normotensive volunteers who were free from disease and not taking medication with cardiovascular or autonomic effects. We measured beat-to-beat arterial blood pressure and used standard surface electrocardiography to record pulse interval under standardized conditions with subjects resting supine as well as during three Valsalva manoeuvres. We performed single, multiple and stepwise regression of patient characteristics against cardiac baroreceptor sensitivity results.

RESULTS

There is a non-linear decline in cardiac baroreceptor sensitivity with advancing age, increasing systolic blood pressure and heart rate values (except for the Valsalva-derived result), but little further decline after the fourth decade. Only age significantly influenced values derived using the Valsalva manoeuvre and impulse response analysis. Using spectral analysis, age, systolic and diastolic blood pressure and heart rate influenced cardiac baroreceptor sensitivity, age contributing to 50% of the variability. Age also influenced the relationship between pulse interval and blood pressure, possibly indicating more non-baroreceptor-mediated changes with advancing age.

CONCLUSIONS

Although age is the dominant factor influencing cardiac baroreceptor sensitivity in this normotensive population, there is little change in mean values after 40 years of age. The differences in the relationship between pulse interval and blood pressure with advancing age have implications for the calculation of cardiac baroreceptor sensitivity using spectral analysis.

Baroreflex sensitivity changes with calcium antagonist therapy in elderly subjects with isolated systolic hypertension

In order to study the effects of calcium-blocking therapy on cardiovascular homeostasis in elderly subjects with isolated systolic hypertension, we performed a randomised double-blind placebo-controlled crossover study of 6 weeks therapy with modified-release nifedipine or placebo. Changes with calcium-blocker treatment in clinic and 24-h blood pressure (BP), heart rate, BP variability, baroreflex sensitivity (BRS) by three methods (Valsalva manoeuvre, phenylephrine and sodium nitroprusside injection), and in baroreflex- and non-baroreflex-mediated reflexes (tilt and cold face stimulus) were studied in 14 elderly subjects (mean age [+/- SEM] 70 +/- 1 years) with sustained isolated systolic hypertension (clinic BP 179 +/- 3/85 +/- 1 mm Hg). Clinic systolic BP, but not diastolic BP, was reduced with treatment (by 14 +/- 6 mm Hg, P = 0.03, diastolic BP 4 +/- 3 mm Hg, P = 0.16). Twenty-four hour BP was also reduced by nifedipine treatment (by 18 +/- 3/9 +/- 2 mm Hg, both P < 0.001). Clinic and 24-h heart rate, and daytime BP variability, were unchanged with treatment. BRS was significantly increased during nifedipine therapy by all three measurement methods (all P < 0.05). With 60 degrees tilt during active treatment, subjects exhibited a greater heart rate increase (P < 0.01), and a reduced fall in systolic (P < 0.05) and diastolic BP (P < 0.05). Thus despite the arteriosclerosis and reductions in large artery compliance described in elderly patients with isolated systolic hypertension, clinically important improvements in clinic and ambulatory BP and some aspects of cardiovascular homeostasis can be achieved with calcium-channel blocking therapy.

Evidence of defective cardiovascular regulation in insulin-dependent diabetic patients without clinical autonomic dysfunction

(1) Autonomic dysfunction is a well recognised complication of diabetes mellitus and early detection may allow therapeutic manoeuvres to reduce the associated mortality and morbidity. We sought to identify early cardiovascular autonomic neuropathy using spectral analysis of heart rate and systolic blood pressure variability. (2) Thirty patients with Type 1 (insulin-dependent) diabetes mellitus (DM) and 30 matched control subjects were studied. In addition to standard tests of autonomic function, heart rate and systolic blood pressure variability were assessed using power spectral analysis. From the frequency domain analysis of systolic blood pressure and R-R interval, the overall gain of baroreflex mechanisms was assessed. (3) Standard tests of autonomic function were normal in both groups. Total spectral power of R-R interval was reduced in the Type 1 DM group for low-frequency (473 +/- 63 vs. 747 +/- 78 ms2, mean +/- S.E.M., P = 0.002) and high-frequency bands (125 +/- 13 vs. 459+/-90 ms2, P < 0.0001). Systolic blood pressure low-frequency power was increased in the diabetic group (9.3 +/- 1.2 vs. 6.6+/-0.7 mmHg2, P < 0.05). The low frequency/high frequency ratio for heart rate variability was significantly higher in the Type 1 DM patients (4.6+/-0.5 vs. 2.9+/-0.5, P = 0.002), implying a relative sympathetic predominance. When absolute powers were expressed in normalised units, these differences persisted. There were significant reductions in baroreceptor-cardiac reflex sensitivity in Type 1 DM patients compared to controls while supine (9.7+/-0.7 vs. 18.5 +/- 1.7 ms/mmHg, P < 0.0001) and standing (2.9+/-0.9 vs. 7.18+/-1.9 ms/mmHg, P < 0.001). (4) Spectral analysis of cardiovascular variability detects autonomic dysfunction more frequently in Type 1 DM patients than conventional tests, and is suggestive of an abnormality of parasympathetic function. The abnormality of baroreceptor-cardiac reflex sensitivity could be explained by this impairment of parasympathetic function and this may predispose to the development of hypertension and increase the risk of sudden cardiac death. Using spectral analysis methods may allow detection of early diabetic cardiac autonomic neuropathy and allow therapeutic intervention to slow the progression.

Forearm muscle activation during power grip and release

The position of the hand during power grip is well-described, but the normal phasic activity of the extrinsic forearm muscles during power grip and release is unknown. People with neurologic impairment may have inadequate power grip or release because of abnormal muscle timing. This study describes the timing of the forearm muscles in 10 normal subjects during power grip and release, which was evaluated using electromyography. During power grip, subjects had consistent timing patterns for extrinsic finger motors and different but individually consistent patterns for wrist motors. This finding supports our hypothesis that different individuals habitually use a specific motor strategy and an intact central nervous system allows them to change their motor strategy to adapt to new environmental parameters.

Expression of cytokine genes in Aotus monkeys immunized with synthetic and recombinant Plasmodium vivax and P. falciparum antigens

Cytokine responses in human host-protective immunity to malaria have yet to be completely elucidated. No data appear to exist on the cytokine patterns in non-human primate models immunized with malarial antigens. Expression of mRNA transcripts of 10 cytokines, the adhesion molecule ICAM-1 and inducible nitric oxide synthase (iNOS) in peripheral-blood mononuclear cells (PBMC) from nine Aotus monkeys was analysed by reverse-transcriptase PCR. Five of the monkeys had been immunized with multiple-antigen peptides (MAP) of the Plasmodium vivax circumsporozoite protein and two with constructs of the P. falciparum merozoite surface protein-1 (MSP-1). The other two monkeys served as non-immunized controls. PBMC were cultured for 24 h after stimulation with phytohaemagglutinin mitogen, MAP and MSP-1 antigens. Elevated expression of interleukin-6 (IL-6), IL-10, IL-12, tumour necrosis factor-alpha (TNF-alpha), TNF-beta and iNOS was seen in response to the MAP. Monkeys immunized with either P. falciparum MSP r190L or synthetic 190L peptides expressed predominantly the type-1 cytokines (IL-1 beta, IL-12, interferon-gamma, TNF-alpha, TNF-beta) characteristic of splenic, cell-mediated activity with macrophage activation and nitric oxide production.

Differential expression of systemic cytokine profiles in Chagas' disease is associated with endemicity of Trypanosoma cruzi infections

Chagas' disease is a serious public health problem in Paraguay, however, the immunoepidemiology of the disease has not been well documented. A preliminary cross-sectional survey was carried out in two villages of the Paraguayan Chaco region and in five villages of the Oriental region to assess the endemicity of Trypanosoma cruzi infections. Thereafter, a subset of individuals (ages ranging from 23 to 65 years) participated in a follow-up study to evaluate clinical and parasitological parameters. Physical examinations and electrocardiograms (ECG) were conducted and blood samples collected for parasite detection and serology. The most frequent ECG abnormalities which were observed among chagasic individuals were left anterior hemifascicular block and right bundle branch block. Thirty-two of these subjects, seropositive and non-parasitemic from the high endemic Chaco (n = 16) and low endemic Oriental (n = 16) regions, were randomly selected for an analysis of T. cruzi-induced expression of cytokines IL-2, IFN-gamma, IL-4 and IL-10 by RT-PCR. The individuals were grouped (n = 8) according to the presence or absence of abnormal ECG. In subjects that exhibited abnormal ECG profiles, five of eight (63%) individuals from the high endemic area showed a dominant type 2 (IL-4) response, whereas a comparable number (63%) of subjects from the low endemic area expressed a strong type 1 (IFN-gamma) response; the remainder (37%) presented a Th0-type (IFN-gamma, IL-4) response. Subjects with normal ECG showed a defined cytokine profile according to endemicity. All subjects from the high endemic region showed a Th0 response, whereas 100% of the individuals from the low endemic area demonstrated a type 1 response. In most chagasic patients regardless of ECG profile and endemicity, IL-2 expression was depressed, while IL-10 mRNA transcripts were consistently elevated. Taken together, these data indicate that chronic human chagasic disease is associated with increased systemic production of type 2 cytokines in response to T. cruzi infection and may be involved in the reciprocal down-regulation of IL-2 production.

Applicability of new techniques in the assessment of arterial baroreflex sensitivity in the elderly: a comparison with established pharmacological methods

1. There has been considerable interest in techniques recently developed for the study of arterial baroreceptor-cardiac reflex sensitivity based on analysis of spontaneous baroreflex sequences and on spectral analysis. This study examined how these newer techniques agreed with the established pharmacological methods in elderly subjects. 2. In 20 elderly subjects [10 hypertensive (clinic blood pressure 180 +/- 4/88 +/- 2 mmHg) and 10 normotensive (clinic blood pressure 136 +/- 3/73 +/- 2 mmHg)], we assessed baroreflex sensitivity from spontaneous sequences of increasing and decreasing blood pressure and pulse interval and their mean, and from spectral analysis to derive alpha, the index of overall baroreflex gain. Pharmacological baroreflex sensitivity was derived from the blood pressure and pulse interval responses to depressor (sodium nitroprusside) and pressor (phenylephrine) stimuli, and their mean. 3. Baroreflex sensitivity was significantly lower in the hypertensive group by the pharmacological, sequence and spectral methods (all P < 0.05). 4. There was acceptable agreement between pharmacological baroreflex sensitivity and sequences of the same direction, but with some systematic bias. There was also reasonable agreement between pharmacological and spectral baroreflex sensitivity and close agreement without bias between sequence and spectral methods. 5. The newer and established techniques demonstrate acceptable agreement in the elderly, albeit with some systematic bias. Pharmacological methods have enjoyed historical precedence but newer techniques give equivalent results, and are preferable in some circumstances. The newer techniques may be more descriptive of the spontaneous behaviour of the arterial baroreflex at rest rather than under artificially stimulated conditions.

Cytokine responses in Trypanosoma cruzi-infected children in Paraguay

Both parasite and host immune factors may contribute to the development and progression of chronic chagasic cardiomyopathy during Trypanosoma cruzi infections. The present study targeted infected children (5-14 years of age) from an endemic area of Paraguay in an analysis of T. cruzi-specific cytokine profiles. This age group is characteristically the most affected by the early phases of infection. Trypanosoma cruzi-induced cytokine gene expression (interleukin-2 [IL-2], and interferon-gamma [IFN-gamma], IL-4, and IL-10) was studied in 25 seropositive children categorized as being either acute, symptomatic, with Romana's sign (n = 2), or early, indeterminate (postacute, n = 23). Acutely infected children showed a distinct T helper cell-1 (Th1)-type (IFN-gamma) cytokine response to infection. The cytokine pattern that was observed in the seropositive, asymptomatic (early, indeterminate) group was of the Th0 type (expression of both IFN-gamma and IL-4). We hypothesize that selective induction of a Th0-type cytokine pattern is important for development of cell-mediated and humoral immune responses that suppress parasite burden, thereby prolonging the onset or limiting the severity of chronic Chagas' disease later in life.

The reproducibility of cardiac baroreceptor activity assessed non-invasively by spectral sequence techniques

Baroreceptor sensitivity (BRS) is increasingly used as a prognostic indicator in cardiovascular disease. Traditionally it has been measured using invasive techniques with pharmacological manipulation of blood pressure (BP). With the advent of newer methods to measure pulse interval and beat-to-beat changes in BP it is now possible, using sophisticated mathematical modelling techniques, to calculate cardiac BRS non-invasively. However, there are virtually no data on the reproducibility of these newer techniques and what factors may affect the repeatability of these measurements. We studied 39 subjects, aged 22-82 years, with a supine systolic BP range 97-160 mmHg and a diastolic BP range 57-94 mmHg on two occasions between 1 week and 6 months apart. Cardiac BRS was measured by power spectral analysis using Fast Fourier Transformation (FFT), sequence analysis (using up, down and combined sequences) and from phase IV of the Valsalva manoeuvre. There was no significant difference between visits for any of the methods for measuring cardiac BRS. Mean BRS values were similar for FFT (16.7 +/- 11.2 ms/mmHg) and sequence analysis (15.8 +/- 11.4 ms/mmHg); however, results using phase IV of the Valsalva manoeuvre were significantly lower (8.1 +/- 2.9 ms/mmHg, p < 0.0001). The coefficient of variation for the five measures of cardiac BRS varied from 16.8% for Valsalva-derived values to 26.1% for 'down' sequence analysis. However, in ten subjects BRS could not be calculated from the Valsalva manoeuvre. None of the independent variables tested (including age, BP levels and time between testing) significantly influenced the degree of repeatability. In summary, there appears to be little difference between these non-invasive methods in their degree of reproducibility. These techniques would seem suitable for longitudinal studies of changes in cardiac BRS and overcome many of the problems associated with the invasive pharmacological methods.

Feasibility of mathematical models to predict success in video-assisted thoracic surgery lung nodule excision

BACKGROUND

Pulmonary nodules are occasionally difficult to excise using video-assisted thoracic surgery (VATS).

METHODS

To predict operative success, mathematical models using preoperative computerized tomography (CT) measurements were tested in 50 consecutive patients who underwent attempted or successful thoracoscopic lung biopsy. Unrelated technical problems resulted in the exclusion of 3 patients.

RESULTS

No differences were noted with respect to lobar location, thoracic dimensions, gender, presence of chronic obstructive pulmonary disease, or nodule pathology. The expression S/(D + 1), where S = nodule size (cm) and D = distance (cm) to the nearest visceral pleura, yielded significantly higher values for visible nodules (P < 0.001). Resectable nodules had a higher score using the expression 1/(S + D + 1), (P < 0.001). Simple cases (n = 19) were defined as those in which nodules were both visible and resectable with very basic VATS techniques. All others (n = 28) were considered complex. The derived expression for Simplicity [1/(S(D + 1))] yielded significantly higher values for simple cases (0.8 +/- 0.3 vs. 0.3 +/- 0.2 cm(-2), P < 0.001) and all simple cases had a score > or = 0.4. Logistic regression analysis showed that the formulas for resectability and simplicity were significant independent predictors for resectability and simplicity.

CONCLUSIONS

Equations based on objective CT measurements may be useful for planning VATS nodulectomy or studying the outcome of these minimally invasive operations.

Impulse response analysis of baroreceptor sensitivity

The impulse response function (IRF) can express the dynamic relationship between systolic arterial pressure (SAP) and pulse interval (PI) and, consequently, represents an alternative method to assess baroreceptor sensitivity (BRS) in humans. Five normotensive and 13 hypertensive subjects (age 68 +/- 5 yr, range 60-74 yr) were studied at rest in the supine position during baseline conditions and after injections of phenylephrine and sodium nitroprusside. SAP and PI signals were derived from multiple 5-min noninvasive recordings of arterial blood pressure (Finapres) and electrocardiogram. Standard estimates of BRS were obtained by the slopes of transient changes in SAP and PI after the injection of phenylephrine and sodium nitroprusside (BRS(PE) and BRS(SNP)) and by spectral analysis (alpha-index). Impulse responses were obtained by the inverse Fourier transform of the transfer function between PI and SAP. The temporal pattern of the IRF was characterized by a main peak at t = 0, preceded by a "trough" at t = -1 s. A mathematical model of the baroreflex suggests that the peak value of IRF is linearly related to the BRS. The peak value and its smoothed version were shown to be significantly correlated to alpha, BRS(PE), and BRS(SNP) and significantly reduced in the hypertensive group during the three stages of the protocol. We suggest that IRF might be the ideal method to assess BRS because it does not require any subjective preselection of data segments or spectral bands.

Endothelial function in subcutaneous resistance arteries from elderly hypertensive and normotensive subjects

1. Previous studies have indicated that younger hypertensive subjects may have abnormal endothelium-dependent relaxation, which could contribute to the elevated peripheral resistance seen in established hypertension. This study was designed to examine the functional behaviour of the endothelium of small arteries from elderly hypertensive and normotensive subjects. 2. Resistance arteries were obtained from gluteal biopsies taken under local anaesthesia in 28 subjects of mean age 70 (range 60-76) years, and studied in an isometric myograph. Eighteen subjects had untreated essential hypertension, and 10 were normotensive. 3. After measurement of the contractile response to noradrenaline, relaxation responses to a variety of endothelium-dependent (acetylcholine and bradykinin) and endothelium-independent (iloprost and sodium nitroprusside) mechanisms were assessed in vessels precontracted with noradrenaline. Endothelium-dependent responses were also studied after incubation with NG-nitro-L-arginine to inhibit nitric oxide synthase. 4. There were no significant differences in the contraction or relaxation responses between elderly subjects with or without high blood pressure. Inhibition of nitric oxide synthase prevented any relaxation with acetylcholine and significantly attenuated the relaxation with bradykinin. Near-complete relaxation was however achieved with the endothelium-independent vasodilator sodium nitroprusside. 5. Hypertension in elderly subjects is not associated with a reduction in endothelial vasodilating function in the subcutaneous vessels of the gluteal region compared with age-matched normotensive controls. The results of this study do not support the hypothesis of a defect of resistance artery endothelium-dependent relaxation in the pathophysiology of hypertension in the elderly.

Arterial baroreceptor-cardiac reflex sensitivity in the elderly

Uncertainty still remains regarding the differing effects of blood pressure and age on baroreceptor-cardiac reflex sensitivity in elderly individuals; these differences are at least partly due to the differing methods and subject groups used in previous studies. We sought to resolve these issues by examining baroreflex sensitivity in 54 subjects aged 70 +/- 1 years (mean +/- SE; range, 60 to 81) divided into groups with combined systolic-diastolic hypertension (CH group, n = 16), isolated systolic hypertension (ISH group, n = 16), or normotension (NT group, n = 22). Baroreflex sensitivity was quantified from the pulse interval and blood pressure responses to the Valsalva maneuver and pressor (phenylephrine) and depressor (sodium nitroprusside) stimuli. Baroreflex sensitivity was significantly reduced in the two hypertensive groups but did not differ between them (Valsalva maneuver: CH group, 1.9 +/- 0.3 ms/mm Hg; ISH group, 2.8 +/- 0.5; NT group, 4.4 +/- 0.4; phenylephrine: CH group, 3.1 +/- 0.6; ISH group, 3.5 +/- 0.7; NT group, 7.7 +/- 1.0; sodium nitroprusside CH group, 2.1 +/- 0.3; ISH group, 3.6 +/- 0.8; NT group, 5.4 +/- 0.3; all P < .05 for comparison with the NT group). Thus, this study demonstrated reductions in baroreflex sensitivity with hypertension in elderly subjects consistent across all methods but with no difference between subjects with combined hypertension and isolated systolic hypertension matched for similar systolic pressure. Baroreflex sensitivity was related only to the level of systolic pressure independent of diastolic pressure or age. If elderly subjects with isolated systolic hypertension have a greater reduction in large-artery compliance than combined hypertensive subjects with similar systolic pressure, this does not appear to lead to further reductions in baroreflex sensitivity in these individuals.

Assessment of baroreceptor-cardiac reflex sensitivity using time domain analysis in patients with IDDM and the relation to left ventricular mass index

Autonomic dysfunction in insulin-dependent diabetic (IDDM) patients has been associated with abnormalities of left ventricular function and an increased risk of sudden death. A group of 30 patients with IDDM and 30 age, sex and blood pressure matched control subjects underwent traditional tests of autonomic function. In addition, baroreceptor-cardiac reflex sensitivity (BRS) was assessed using time domain (sequence) analysis of systolic blood pressure and pulse interval data recorded non-invasively using the Finapres beat-to-beat blood pressure recording system. 'Up BRS' sequences-increases in systolic blood pressure associated with lengthening of R-R interval, and 'down BRS' sequences-decreases in systolic blood pressure associated with shortening of R-R interval were identified and BRS calculated from the regression of systolic blood pressure on R-R interval for all sequences. We also assessed heart rate variability using power spectral analysis and, after expressing components of the spectrum in normalised units, assessed sympathovagal balance from the ratio of low to high frequency powers. IDDM subjects underwent 2-D echocardiography to assess left ventricular mass index. Standard tests of autonomic function revealed no differences between IDDM patients and control subjects, but dramatic reductions in baroreceptor-cardiac reflex sensitivity were detected in IDDM patients. 'Up BRS' when supine was 11.2 +/- 1.5 ms/mmHg (mean +/- SEM) compared with 20.4 +/- 1.95 in control subjects (p < 0.003) and when standing was 4.1 +/- 1.9 vs 7.6 +/- 2.7 ms/mmHg (p < 0.001). Down BRS when supine was 11.5 +/- 1.2 vs 22 +/- 2.6 (p < 0.001) and standing was 4.4 +/- 1.9 vs 7.3 +/- 2.5 ms/mmHg (p < 0.003). There were significant relations between impairment of the baroreflex and duration of diabetes (p < 0.001) and poor glycaemic control (p < 0.001). From a fast Fourier transformation of supine heart rate data and using a band width of 0.05-0.15 Hz as low-frequency and 0.2-0.35 Hz as high frequency total spectral power of R-R interval variability was significantly reduced in the IDDM group for both low-frequency (473 +/- 62.8 vs 746.6 +/- 77.6 ms2 p = 0.002) and high frequency bands 125.2 +/- 12.9 vs 459.3 +/- 89.8 ms2 p < 0.0001. When the absolute powers were expressed in normalised units the ratio of low frequency to high frequency power (a measure of sympathovagal balance) was significantly increased in the IDDM group (2.9 +/- 0.53 vs 4.6 +/- 0.55, p < 0.002 supine: 3.8 +/- 0.49 vs 6.6 +/- 0.55, p < 0.001 standing). Thus, time domain analysis of baroreceptor-cardiac reflex sensitivity detects autonomic dysfunction more frequently in IDDM patients than conventional tests. Impaired BRS is associated with an increased left ventricular mass index and this abnormality may have a role in the increased incidence of sudden death seen in young IDDM patients.

Abnormal baroreceptor-cardiac reflex sensitivity is not detected by conventional tests of autonomic function in patients with insulin-dependent diabetes mellitus

1. Autonomic neuropathy is a common complication of diabetes mellitus and is a major risk factor for sudden death. 2. A group of 30 patients with insulin-dependent diabetes mellitus and 30 age-, sex- and blood pressure-matched control subjects underwent traditional tests of autonomic function. Resting supine R-R interval and systolic blood pressure variability were assessed using spectral analysis methods. In addition, we assessed the baroreceptor-cardiac reflex from the linear relation of the change in R-R interval to the increasing systolic blood pressure measured non-invasively with the Finapres monitor during phase 4 of the Valsalva manoeuvre and from resting heart rate and systolic blood pressure power spectra. 3. Whereas standard tests of autonomic function revealed no differences between patients with insulin-dependent diabetes mellitus and control subjects, there was a significant reduction in power spectral density of heart rate variability around the high-frequency region (125.2 +/- 112.9 versus 459.3 +/- 189.8 ms2, mean +/- SD). Furthermore, reductions in baroreflex sensitivity calculated from the Valsalva manoeuvre were detected in diabetics compared with controls (3.3 +/- 1.6 versus 9.5 +/- 2.5 ms/mmHg, mean +/- SD, P < 0.00001). There were significant relations between impairment of the baroreflex and duration of diabetes (P < 0.001) and poor diabetic control (P < 0.05). 4. In summary, autonomic dysfunction occurs much more frequently in diabetic patients than conventional tests would suggest. Abnormal baroreceptor-cardiac reflex sensitivity in patients with insulin-dependent diabetes mellitus may in part be explained by abnormal parasympathetic function. This unrecognized abnormality may have a role in the increased incidence of sudden death seen in young diabetic subjects.

Comparison of diurnal systolic blood pressure change as defined by wrist actigraphy, fixed time periods and cusum

AIMS

To assess whether differences exist in nocturnal blood pressure (BP) levels and the diurnal BP change when using fixed time and wrist actigraphy methods to define the night-time period.

METHODS

Untreated hypertensive (n = 48) and normotensive (n = 33) subjects (mean age 67 years: range 29-90) underwent simultaneous 24-h ambulatory BP monitoring and wrist actigraph monitoring. The diurnal BP change and nocturnal BP levels were assessed using two fixed night-time definitions-a reference period of 22.00-06.59 and also 00.00-05.59, as well as unedited and edited actigraph values and cumulative sums (cusums) analysis.

RESULTS

The reference definition of night-time 22.00-06.59 resulted in the highest values for night-time BP compared to other definitions (p < 0.05), although actigraph defined night-time BP values were not significantly different from the more restrictive definition of night-time (00.00-05.59). Restrictive night-time, edited and unedited actigraph and cusums values for the day-night difference were all significantly greater than the value calculated using the reference night-time period. Dipping status changed significantly depending on which definition of night-time was used.

CONCLUSIONS

Significant differences exist in nocturnal BP levels and circadian change between the various methods for defining night-time. The routine use of wrist actigraphy does not however appear to alter the value of night-time BP levels when compared to a more restrictive fixed-time definition of night-time.

Characteristics of patients with hypoplastic thumbs

The records of 98 patients with 160 hypoplastic thumbs seen between 1923 and 1993 were reviewed to determine the salient characteristics of this population. Physical findings, photographs, and x-ray films were studied. Sixty-three percent of patients were male, and 63% had bilateral thumb hypoplasia, 59% had radial dysplasia, and 86% had other anomalies. An associated syndrome, most commonly the vertebral, anal, tracheosophageal, renal, and radial limb anomalies association or Holt-Oram syndrome, was present in 44%. Patients with spine, genitourinary, or gastrointestinal anomalies were most likely to have the vertebral, anal, tracheosophageal, renal, and radial limb anomalies association, those with cardiac anomalies were most likely to have Holt-Oram syndrome, and those with lower extremity anomalies were most likely to have a different syndrome. One hundred thirty-nine thumbs were classifiable, using a modification of Blauth's classification; 19% were types 1 and 2, 23% were type 3, and 58% were types 4 and 5. One hundred seven operations were performed on 63 upper limbs, including 24 thumb reconstructions and 35 pollicizations. These patients must be carefully examined for bilaterality, other anomalies, and syndromes. Classification using a modification of Blauth's criteria is useful and helps the surgeon determine a treatment plan.

Reproducibility of the circadian systolic blood pressure variation in the elderly

OBJECTIVES

To establish the reproducibility of the nocturnal systolic blood pressure (SBP) change in elderly subjects and to examine the use of cumulative sums (cusums) analysis in the assessment of circadian SBP variation.

SUBJECTS

Forty-two untreated elderly subjects (35 hypertensive, 7 normotensive) of mean age 75.5 years from the hypertension clinic at a large teaching hospital participated in a reproducibility study.

METHODS

Twenty-four-hour ambulatory blood pressure monitoring was performed and repeated at a median interval of 2 months (range 2 weeks to 9 months).

OUTCOME MEASURES

Reproducibility of circadian SBP variation from fixed time analysis of day-night SBP difference and from cusums-based parameters.

RESULTS

Twenty-four-hour SBP values were highly reproducible with a coefficient of variation of 5.8%. However, the day-night SBP difference for fixed time periods was poorly reproducible, with a coefficient of variation > 130%. A substantial proportion of subjects (36-43%) altered their 'dipping status' between visits. The use of cusums analysis improved the reproducibility of measures of circadian SBP change (cusums plot height and maximum circadian variation) with coefficients of variation falling to 40 and 38%, respectively.

CONCLUSIONS

The use of fixed time definitions results in poor reproducibility of the circadian SBP change in the elderly, which will lead to regression dilution bias when studying the relationship of circadian SBP variation to outcome measures in hypertension. The notion of dipping and non-dipping circadian blood pressure patterns should be abandoned in favour of more reproducible cusums-based measures of circadian blood pressure variation.

Pulse pressure and resistance artery structure in the elderly

There has been recent interest in the possibility that resistance vessel structural adaptation in hypertension may be more closely related to pulse pressure than to other blood pressure parameters. We investigated the relation between blood pressure and resistance vessel structure in a group of subjects from an age group (older than 60 years) in which a widening of pulse pressure is a typical finding and characterized blood pressure parameters using 24-hour ambulatory blood pressure monitoring. We studied resistance vessels retrieved from biopsies of skin and subcutaneous fat taken from the gluteal region of 32 subjects under local anesthesia (age, 70 +/- 1 years [mean +/- SEM], 21 of whom were hypertensive and 11 normotensive. Media-lumen ratio was higher in the hypertensive than the normotensive subjects (18.6 +/- 1.6% versus 12.8 +/- 1.2%, P < .01) and correlated with age (r = .44, P < .05), clinic systolic pressure (r = .35, P < .05), 24-hour systolic pressure (r = .40, P < .05), and 24-hour pulse pressure (r = .56, P < .001). Stepwise multivariate regression analysis identified clinic and 24-hour pulse pressure as the only significant predictors of media-lumen ratio independent of age, other parameters of clinic blood pressure, and blood pressure variability (R2 = 41%, P < .05). These findings confirm those from animal models of hypertension in demonstrating the importance of pulse pressure in relation to cardiovascular structural adaptation and have important implications for the goals of treatment of hypertension in the elderly.