Reconstructive vascular surgery in diabetic patients with peripheral arterial insufficiency

Peripheral arterial insufficiency in diabetic patients is for vascular surgeons a special problem as there even may be a distal diabetic angiopathy in the leg arteries. Preoperative adequate evaluation and selection of the patients is necessary before vascular reconstruction. Of 100 consecutive patients operated on with femoropopliteal bypass 33 were diabetic and 67 nondiabetic. Eleven of the diabetic patients were one year later asymptomatic, eight improved but eight were amputated.

Characteristics and outcome amongst young adults suffering from out-of-hospital cardiac arrest in whom cardiopulmonary resuscitation is attempted

OBJECTIVES

Amongst patients suffering from out-of-hospital cardiac arrest, young adults represent a minority. However, these victims suffer from the catastrophe when they are in a very active phase of life and have a long life expectancy. This survey aims to describe young adults in Sweden who suffer from out-of-hospital cardiac arrest and in whom cardiopulmonary resuscitation (CPR) is attempted in terms of characteristics and outcome.

DESIGN

Prospective and descriptive design.

SUBJECTS AND METHODS

Young adults (18-35 years) who suffered from out-of-hospital cardiac arrest in whom CPR was attempted and who were included in the Swedish Cardiac Arrest Registry between 1990 and 2004.

MAIN OUTCOME MEASURES

Survival to 1 month.

RESULTS

In all, 1105 young adults (3.1% of all the patients in the registry) were included, of which 29% were females, 51% were nonwitnessed and 15% had a cardiac aetiology. Only 17% were found in ventricular fibrillation, 53% received bystander CPR. The overall survival to 1 month was 6.3%. High survival was found amongst patients found in ventricular fibrillation (20.8%) and those with a cardiac aetiology (14.8%). Ventricular fibrillation at the arrival of the rescue team remained an independent predictor of an increased chance of survival (odds ratio: 7.43; 95% confidence interval: 3.44-16.65).

CONCLUSION

Amongst young adults suffering from out-of-hospital cardiac arrest and in whom CPR was attempted, a minority survived to 1 month. Subgroups with a higher survival could be defined (patients found in ventricular fibrillation and patients in whom there was a cardiac aetiology). However, only one independent predictor of an increased chance of survival could be demonstrated, i.e. ventricular fibrillation at the arrival of the rescue team.

Association between interval between call for ambulance and return of spontaneous circulation and survival in out-of-hospital cardiac arrest

AIM

To describe the association between the interval between the call for ambulance and return of spontaneous circulation (ROSC) and survival in out-of-hospital cardiac arrest.

PATIENTS

All patients suffering an out-of-hospital cardiac arrest in whom cardiopulmonary resuscitation (CPR) was started, included in the Swedish Cardiac Arrest Registry (SCAR) for whom information about the time of calling for an ambulance and the time of ROSC was available.

RESULTS

Among 26,192 patients who were included in SCAR and were not witnessed by the ambulance crew, information about the time of call for an ambulance and the time of ROSC was available in 4847 patients (19%). There was a very strong relationship between the interval between call for an ambulance and ROSC and survival to one month. If the interval was less than or equal to 5 min, 47% survived to one month. If the interval exceeded 30 min, only 5% (n = 35) survived to one month. The vast majority of the latter survivors had a shockable rhythm either on admission of the rescue team or at some time during resuscitation.

CONCLUSION

Among patients who have ROSC after an out-of-hospital cardiac arrest, there is a very strong association between the interval between the call for ambulance and ROSC and survival to one month. However, even if this delay is very long (> 30 min after calling for an ambulance), a small percentage will ultimately survive; they are mainly patients who at some time during resuscitation have a shockable rhythm. The overall percentage of patients for whom CPR continued for more than 30 min who are alive one month later can be assumed to be extremely low.

Major differences in 1-month survival between hospitals in Sweden among initial survivors of out-of-hospital cardiac arrest

AIM

To explore the rate of survival to hospital discharge among patients who were brought to hospital alive after an out-of-hospital cardiac arrest in different hospitals in Sweden.

PATIENTS AND METHODS

All patients who had suffered an out-of-hospital cardiac arrest which was not witnessed by the ambulance crew, in whom cardiopulmonary resuscitation (CPR) was started and who had a palpable pulse on admission to hospital were evaluated for inclusion. Each participating ambulance organisation and its corresponding hospital(s) required at least 50 patients fulfilling these criteria.

RESULTS

Three thousand eight hundred and fifty three patients who were brought to hospital by 21 different ambulance organisations fulfilled the inclusion criteria. The number of patients rescued by each ambulance organisation varied between 55 and 900. The survival rate, defined as alive 1 month after cardiac arrest, varied from 14% to 42%. When correcting for dissimilarities in characteristics and factors of the resuscitation, the adjusted odds ratio for survival to 1 month among patients brought to hospital alive in the three ambulance organisations with the highest survival versus the three with the lowest survival was 2.63 (95% CI: 1.77-3.88).

CONCLUSION

There is a marked variability between hospitals in the rate of 1-month survival among patients who were alive on hospital admission after an out-of-hospital cardiac arrest. One possible contributory factor is the standard of post-resuscitation care.

Characteristics and outcome among children suffering from out of hospital cardiac arrest in Sweden

AIM

To evaluate the characteristics, outcome and prognostic factors among children suffering from out of hospital cardiac arrest in Sweden.

METHODS

Patients aged below 18 years suffering from out of hospital cardiac arrest which were not crew witnessed and included in the Swedish cardiac arrest registry were included in the survey. This survey included the period 1990-2001 and 60 ambulance organisations covering 85% of the Swedish population (8 million inhabitants).

RESULTS

In all 457 children participated in the survey of which 32% were bystander witnessed and 68% received bystander CPR. Ventricular fibrillation was found in 6% of the cases. The overall survival to 1 month was 4%. The aetiology was sudden infant death syndrome in 34% and cardiac in 11%. When in a multivariate analysis considering age, sex, witnessed status, bystander CPR, initial rhythm, aetiology and the interval between call for, and arrival of, the ambulance and place of arrest only one appeared as an independent predictor of an increased chance of surviving cardiac arrest occurring outside home (adjusted odds ratio 8.7; 95% CL 2.2-58.1).

CONCLUSION

Among children suffering from out of hospital cardiac arrest in Sweden that were not crew witnessed, the overall survival is low (4%). The chance of survival appears to be markedly increased if the arrest occurs outside the patients home compared with at home. No other strong predictors for an increased chance of survival could be demonstrated.

Can we define patients with no chance of survival after out-of-hospital cardiac arrest?

OBJECTIVE

To evaluate whether subgroups of patients with no chance of survival can be defined among patients with out-of-hospital cardiac arrest.

PATIENTS

Patients in the Swedish cardiac arrest registry who fulfilled the following criteria were surveyed: cardiopulmonary resuscitation (CPR) was attempted; the arrest was not crew witnessed; and patients were found in a non-shockable rhythm.

SETTING

Various ambulance organisations in Sweden.

DESIGN

Prospective observational study.

RESULTS

Among the 16,712 patients who fulfilled the inclusion criteria, the following factors were independently associated with a lower chance of survival one month after cardiac arrest: no bystander CPR; non-witnessed cardiac arrest; cardiac arrest occurring at home; increasing interval between call for and arrival of the ambulance; and increasing age. When these factors were considered simultaneously two groups with no survivors were defined. In both groups patients were found in a non-shockable rhythm, no bystander CPR was attempted, the arrest was non-witnessed, the arrest took place at home. In one group the interval between call for and arrival of ambulance exceeded 12 minutes. In the other group patients were older than 80 years and the interval between call for and arrival of the ambulance exceeded eight minutes.

CONCLUSION

Among patients who had an out-of-hospital cardiac arrest and were found in a non-shockable rhythm the following factors were associated with a low chance of survival: no bystander CPR, non-witnessed cardiac arrest, the arrest took place at home, increasing interval between call for and arrival of ambulance, and increasing age. When these factors were considered simultaneously, groups with no survivors could be defined. In such groups the ambulance crew may refrain from starting CPR.

Prediction of development of fatigue during a simulated ambulance work task from physical performance tests

The aims of this study were (1) to identify which physical performance tests could best explain the development of fatigue during a simulated ambulance work task, (2) to investigate the effect of height and weight and (3) to investigate in what respects these findings differ between female and male ambulance personnel. Forty-eight male and 17 female ambulance personnel completed a test battery assessing cardio-respiratory capacity, muscular strength and endurance, and co-ordination. The subjects also completed a simulated ambulance work task -- carrying a loaded stretcher. The work task was evaluated by development of fatigue. Univariate and multiple regression analyses were used to investigate to what extent the tests in the test battery were able to explain the variance of developed fatigue. The explained variance was higher for female than for male ambulance personnel (time > 70% of HRpeak: R2 = 0.75 vs 0.10, accumulated lactate: R2 = 0.62 vs 0.42, perceived exertion: R2 = 0.75 vs 0.10). Significant predictors in the models were VO2max, isometric back endurance, one-leg rising, isokinetic knee flexion and shoulder extension strength. Height, but not weight, could further explain the variance. The high physical strain during carrying the loaded stretcher implies the importance of investigating whether improved performance, matching the occupational demands, could decrease the development of fatigue during strenuous tasks.

Does Lipoprotein(a) Inhibit Elastolysis in Abdominal Aortic Aneurysms?

PURPOSE

to test the hypothesis that there is a negative association between serum levels of lipoprotein(a) (Lp(a)) and elastin-derived peptides (EDP) as well as matrix metalloproteinase (MMP)-9 activation in the aneurysm wall in patients with asymptomatic abdominal aortic aneurysms (AAA).

MATERIAL AND METHODS

from 30 patients operated for asymptomatic AAAs, preoperative serum samples and AAA biopsies were collected. Lp(a) (mg/L) and EDP (ng/ml) in serum were measured by enzyme linked immunosorbent assays. MMP-9 activity (arbitrary units) in the AAA wall was measured by gelatin zymography and the ratio: active MMP-9/total MMP-9 were calculated.

RESULTS

there was a significant negative correlation (Spearman's rho) between serum levels of Lp(a) and EDP (r= -0.707, p<0.001), as well as the share of activated MMP-9 (r= -0.461, p=0.01) in the AAA wall.

CONCLUSION

this preliminary study indicate that Lp(a) inhibit elastolysis in asymptomatic AAA.

Serum concentrations of elastin-derived peptides in patients with specific manifestations of atherosclerotic disease

OBJECTIVE

To measure serum concentrations of elastin-derived peptides (S-EDP) in patients with aneurysmal, occlusive and ulcerative manifestations of atherosclerotic disease.

MATERIALS AND METHODS

S-EDP concentrations were measured by a competitive enzyme-linked immunosorbent assay in 10 patients with infrarenal aneurysms 5cm in diameter (AAA), 10 patients with distal aortic occlusive disease (AOD), 10 patients with symptomatic carotid stenosis (>or=70%) and plaque ulceration (SCS) and a control group of 10 patients with no similar specific manifestations of atherosclerotic disease (NAM).

RESULTS

S-EDP concentrations (median, range) were significantly higher in patients with AAA (42ng/ml, 35-52, p<0.001) and SCS (49ng/ml, 37-60, p<0.001) but not AOD (28ng/ml, 22-38, p=0.240) compared to NAM (26ng/ml, 19-36) patients.

CONCLUSION

Increased concentrations of S-EDP were associated with aneurysmal and ulcerative, but not occlusive, manifestations of atherosclerosis.

Presence of Chlamydia pneumoniae in abdominal aortic aneurysms is not associated with increased activity of matrix metalloproteinases

OBJECTIVE

to test the hypothesis that the presence of Chlamydia pneumoniae (C. pneumoniae) in the wall of abdominal aortic aneurysms (AAA) is associated with increased activity of matrix metalloproteinase (MMP)-2 and/or MMP-9.

DESIGN

case-control study.

MATERIAL AND METHODS

in a series of 40 patients with AAA > or =5cm in maximal cross-sectional diameter, C. pneumoniae-DNA was identified in the aneurysm wall by nested PCR in 14 (35%) patients. Another 14 C. pneumoniae-DNA-negative AAA patients from the same series, matched for gender and aneurysm diameter, were used as controls. In each group there were 7 asymptomatic (aAAA) and 7 ruptured (rAAA) aneurysms. MMP-2 and -9 activity was estimated in AAA wall biopsies by gelatin zymography.

RESULTS

patients with a C. pneumoniae-DNA-positive aneurysm wall specimen showed an over-all lower activity of MMP-2 and MMP-9 (pro- and active enzyme) compared to the C. pneumoniae-DNA negative patients. However, there were no statistically significant differences in MMP activity between the two groups of patients with aAAA. Among patients with rAAA both pro-MMP-9 (p=0,026) and active-MMP-9 (p=0.007) were significantly lower in C. pneumoniae-DNA-positive patients compared to C. pneumoniae-DNA-negative patients, whereas there were no significant differences in pro-MMP-2 or active-MMP-2.

CONCLUSION

this preliminary study does not support the hypothesis that the presence of C. pneumoniae in the AAA wall is associated with increased activity of MMP-2 and MMP-9.

Intestinal pHi studied with continuous saline tonometry during ischaemia and reperfusion in the pig

OBJECTIVE

To evaluate continuous saline tonometry for detection of progressive intestinal ischaemia and reperfusion in a porcine model.

DESIGN

In eight anaesthetised pigs, small bowel mucosal pCO2 was recorded by means of two identical equipments for continuous saline tonometry and a standard tonometry balloon during ischaemia and reperfusion.

RESULTS

Both systems of saline tonometry functioned stably during the four hour protocol ischaemia, although not significant until after 45 min for one of the tonometers.

CONCLUSION

The equipment for continuous saline tonometry has a good reactivity, an accuracy comparable with standard tonometry.

Proteolysis of the abdominal aortic aneurysm wall and the association with rupture

PURPOSE

to investigate proteolysis of the abdominal aortic aneurysm (AAA) wall and the association with rupture.

METHODS

levels of matrix metalloproteinases (MMP-2 and MMP-9) and tissue inhibitor of metalloproteinases (TIMP-1 and TIMP-2) were measured in the walls of medium-sized (5-7 cm in diameter) ruptured AAA (rAAA) (n =30) and large (> or = 7 cm in diameter) asymptomatic AAA (aAAA) (n=30).

RESULTS

MMP-2 levels (median, range) were significantly higher in the walls of large aAAA (165 ng/g AAA tissue, 50-840) than from medium-sized rAAA (110 ng/g AAA tissue, 47-547, p=0.007). MMP-9 levels were significantly higher in the walls of medium-sized rAAA (107 ng/g AAA tissue, 19-582) than from large aAAA (55 ng/g AAA tissue, 11-278, p=0.012). TIMP-1 and TIMP-2 levels were equivalent. There was a positive correlation between MMP-2 and the diameter of aAAA (r=0.54, p=0.002), but a negative correlation with MMP-9 (r= -0.44, p=0.017). No significant correlations were found between aAAA diameter and TIMP-1 or TIMP-2.

CONCLUSION

AAA rupture is associated with higher levels of MMP-9. There is no association with TIMP-1 or TIMP-2 levels. MMP-2 levels are positively, whereas MMP-9 levels are negatively, correlated with aAAA size. MMP-9 may play a role in the progression towards rupture, whereas MMP-2 may play a role in expansion.

In vitro degradation of aortic elastin by Chlamydia pneumoniae

OBJECTIVES

to investigate whether Chlamydia pneumoniae (C. pneumoniae) may increase elastin degradation in the aortic wall.

MATERIALS AND METHODS

eighteen full thickness aortic wall samples from non-aneurysmal infrarenal abdominal aortas were collected from autopsies. Two adjacent and equally large pieces were cut out of each aortic sample. From each sample, one piece was incubated in a HEp-2 cell culture infected with C. pneumoniae and the other piece was incubated in an uninfected HEp-2 cell culture. The incubation time was one week at 35 degrees C. The concentration of elastin-derived peptides (EDP) (ng/ml) in the medium of each cell culture was measured in duplicate. For each paired sample, delta-EDP (EDP in HEp-2 cell culture infected with C. pneumoniae- EDP in uninfected HEp-2 cell culture) was calculated.

RESULT

there was a significantly increased degradation of aortic elastin, estimated by EDP concentrations in cell culture conditioned medium, when aortic wall samples were incubated in C. pneumoniae cultures compared with uninfected cultures (p=0.025, Wilcoxon signed ranks test).

CONCLUSION

these results indicate that there is a relationship between the presence of C. pneumoniae and increased elastin degradation in the aortic wall in vitro. This suggests C. pneumoniae in the aortic wall directly or indirectly leads to the degradation of aortic elastin.

Validation of a novel method for continuous saline tonometry in a porcine model

Only intermittent and semi-continuous tonometric measurement of gastric and intestinal pHi is possible with the equipment available today. Earlier we developed a system for continuous saline tonometry and tested it in vitro. To assess the in vivo reliability of this method for continuous gastrointestinal saline tonometry, a standard tonometer for measurement of intestinal pCO2 and corresponding pHi was modified to allow continuous perfusion of physiological saline in a closed system and tested in a porcine model. In 11 anaesthetized and haemodynamically stable pigs, two continuous tonometry balloons were inserted into the distal small bowel, and a standard tonometry balloon was used as reference. To test long-term function of the continuous tonometers the research protocol lasted for eight hours. The two continuous saline tonometers performed well, and after an equilibration time of three hours the mean pHi values were stable between 7.35 and 7.43 and between 7.32 and 7.39 respectively. The standard tonometer measured stable pHi values. These preliminary studies indicate that continuous saline tonometry performs well over eight hours with a small bias and a good precision.

Serum levels of elastin-derived peptides in patients with ruptured and asymptomatic abdominal aortic aneurysms

OBJECTIVE

to determine whether serum elastin-derived peptides (S-EDP), are lower in patients with ruptured abdominal aortic aneurysms (rAAA) than asymptomatic (aAAA).

MATERIALS AND METHODS

serum samples were collected preoperatively from 45 consecutive patients with aAAA and 15 haemodynamically stable patients with rAAA. S-EDP (ng/ml) was measured by a competitive enzyme-linked immunosorbent assay (ELISA).

RESULTS

S-EDP (mean +/- s.d.) was significantly lower in patients with rAAA (31.6 ng/ml +/- 6.8) than in patients with aAAA (39.4 ng/ml +/- 8.0 p=0.001).

CONCLUSION

patients with rAAA had significantly lower levels of S-EDP than patients with aAAA. The possibility that S-EDP can be used to identify patients at increased risk of rupture requires further investigation.

Geriatric-based versus general wards for older acute medical patients: a randomized comparison of outcomes and use of resources

BACKGROUND

The effects of residence in an acute geriatrics-based ward (AGW) with emphasis on early rehabilitation and discharge planning for older patients with acute medical illnesses were assessed. Outcome and use of resources were compared with those of patients treated in general medical wards (MWs). A per-protocol rather than intention-to-treat analysis was performed.

METHODS

A randomized trial with 3-months follow-up. A total of 190 patients aged 70 years and older were randomized to an acute geriatrics-based ward, and 223 patients were randomized to general medical wards.

RESULTS

The two groups were comparable at inclusion. However, after care in the AGW, 71% of patients could be discharged directly home compared with 64% of those treated in MWs (relative risk 1.17; 95% CI, 0.93-1.49). The length of stay was shorter in the AGW (mean 5.9 vs 7.3 days; P = .002). The proportion of patients in geriatric or other hospital wards or in nursing homes did not differ, but the proportion of AGW patients in sheltered living tended to be lower (P = .085). At the follow-up, case fatality, ADL function, psychological well-being, need for daily personal assistance, drug consumption, need for readmission to hospital, and total health care costs after discharge did not differ between the two groups. Poor global outcome was observed in 37% of AGW and 34% of MW patients.

CONCLUSIONS

A geriatric approach with greater emphasis on early rehabilitation and discharge planning in the AGW shortened the length of hospital stay and may have reduced the need for long-term institutional living. This occurred despite patients in an acute geriatric ward not having better medical or functional outcome than older acute patients treated in general medical wards.

Activity of matrix metalloproteinase-2 and -9 in abdominal aortic aneurysms. Relation to size and rupture

OBJECTIVES

to investigate the activity of matrix metalloproteinase (MMP)-2 and -9 in asymptomatic abdominal aortic aneurysms (aAAAs) and ruptured abdominal aortic aneurysms (rAAAs).

DESIGN

cross-sectional study.

MATERIALS AND METHODS

MMP-2 and MMP-9 activity was estimated in biopsies from the anterior wall of 60 AAAs using gelatin zymography. There were 20 medium-sized (diameter 5<7 cm) aAAAs, 20 large (>57 cm) aAAAs and 20 rAAAs. MMP activity was quantified using a laser densitometer and expressed as arbitrary units (au).

RESULTS

mean (SEM) MMP-9 activity was significantly lower in large aAAAs (1190 au +/-247) than in rAAAs (2647 au +/-498, p<0.05). There was no difference in MMP-2 activity.

CONCLUSION

High MMP-9 activity in the AAA wall is associated with rupture.

A new method for continuous tonometric pCO2 measurement--in vitro studies

The available methods for tonometric pCO2 measurement only provide the possibility of performing intermittent registrations. A new method allowing continuous tonometric pCO2 measurement has been developed and tested in an in vitro model. A standard tonometer for intestinal pCO2 measurement was modified to allow continuous perfusion of the balloon with physiological saline solution in a closed system. The pCO2 in the system was determined in a specially constructed measurement chamber with a TCM20 percutaneous pCO2 monitor. In this in vitro model the tonometer balloon was placed in a saline bath with a constant pCO2 concentration and the measurements from the closed circulating system were compared with those obtained from a standard tonometer placed in the same bath. In 8 and 24 h experiments the circulating system measured the pCO2 value as accurately and reliably as traditional tonometry. This study indicates that the new method makes continuous monitoring of pCO2 possible.

A tactile sensor for detection of physical properties of human skin in vivo

A spring loaded tactile sensor with displacement sensing has been evaluated for non-invasive assessment of physical properties, stiffness and elasticity, of human skin in vivo. The tactile sensor consists of a peizoelectric vibrator (61 kHz) with a vibration pickup, electronics and PC with software for measurement of the change in frequency when the sensor is attached to an object. Integrated with the tactile sensor is a displacement sensor that shows the compression of the spring that loads the sensor element against the object during measurement. Under certain conditions (e.g. fixed contact pressure) this change in frequency monitors the acoustic impedance of the object and is related to the stiffness of soft tissue. The experimental results on silicone gum and on healthy Japanese and Swedish women indicated that the instrument was able to detect changes in stiffness and elastic related properties of human skin, related to age, day-to-day variations and application of cosmetics. The instrument was concluded to be easy to handle and suitable for field work.

Non-invasive assessment of intercompartmental fluid shifts in burn victims

Two non-invasive methods (the bioimpedance technique, BIA, and the impression method, IM) were studied, to find out whether they are sensitive enough to detect and chronicle the development of the oedema and fluid resuscitation effects (Parkland formula) that occur secondary to a major burn. Ten patients with a total burned body surface area (TBSA) of more than 10% were included in this prospective study. Total body water (TBW), as measured by the resistance (BIA) or F(0) variable (IM), reached a maximum on day 2. The tissue fluid translocation (INT) variable (IM) followed a different course, increasing slowly to reach a maximum on day 6, when it was 40% higher than the 12 h value. TBW and the interstitial translocatable fluid were still increased 1 week post-burn. The non-invasive measurements of TBW (resistance by BIA and F(0) by IM) reflected the anticipated changes in TBW. The phase angle (BIA) indicative of cellular membrane effects of burn and sepsis had its lowest values at day 1.5, and stayed significantly low until day 4. Interestingly, the phase angle was lowest in the two cases that died subsequently. The different time course of the INT value (IM), which reflected the translocatable interstitial fluid volume in skin, may be the result of resuscitation fluid remaining in this compartment, due to the excess sodium content together with a possible change in tissue compliance secondary to the early total water peak on day 2.

Chlamydia pneumoniae in human abdominal aortic aneurysms

OBJECTIVES

To investigate the presence of Chlamydia pneumoniae DNA in the wall of infrarenal abdominal aortic aneurysms, and in the wall of non-aneurysmal infrarenal abdominal aortas.

DESIGN

Case-control study.

MATERIALS AND METHODS

The study group consisted of 40 patients operated transperitoneally for an infrarenal abdominal aortic aneurysm (IAAA) (eight females, 32 males; mean age 69 years, median age 68 years). Specimens from the aneurysm wall were taken peroperatively under sterile conditions. The control group consisted of 40 deceased persons without aortic aneurysms (14 females, 26 males; mean age 71 years, median age 70 years). Specimens from the non-aneurysmal infrarenal aortas (NIAA) were collected within 48 h after death. The specimens from both groups were frozen at -70 degrees C immediately after collection. A nested polymerase chain reaction (PCR) method, using two sets of primers designed to detect a fragment of the major outer membrane protein gene of C. pneumoniae, was used.

RESULTS

The detection of C. pneumoniae-specific DNA was significantly higher in the study group (14/40 = 35%) than in the control group (2/40 = 5%); (p = 0.001). No clinical factor predicting the presence of C. pneumoniae in the aneurysm wall, could be found.

CONCLUSION

Chlamydia pneumoniae was detected at a significantly higher frequency in the wall of IAAAs than in the wall of NIAAs. Although this finding does not prove that C. pneumoniae causes IAAAs, further studies on the possible role of C. pneumoniae in the pathogenesis of aneurysms should be performed.

Linell classification of breast cancer morphology compared to histologic grading, S-phase fraction and DNA-ploidy

One hundred and fifty-eight histologically verified mammary carcinomas with known mammographic doubling time (DT) were studied with special emphasis on a morphologic classification proposed by Linell et al. [8, 12, 14, 15]. The hypothesis that Linell classification of ductal carcinomas into comedo, tubuloductal and tubular carcinomas is easy to perform with small inter-observer variations, was not fully confirmed. The Linell classification was found to correlate well with conventional WHO malignancy grading, S-phase fraction and DNA-ploidy. The Linell classification also correlated to surgical stage, lymph node status and DT, but not at all to tumour size. Using distant disease-free survival as an endpoint, the Linell classification gave prognostic information comparable to conventional histologic grading, seeming to be a simple, cheap and reliable method well worth trying on a larger scale.

Two-dimensional high-resolution electrophoresis of elastin-derived peptides

Degradation of human aortic elastin in vivo yields a restricted number of differentially sized and charged peptides. Elastin-derived peptides (EDP) can be analyzed by two-dimensional electrophoresis after their extraction from human abdominal aortic tissue by 0.2 M sodium chloride. The peptides were separated according to charge by acetic acid-urea-PAGE and then according to molecular mass by SDS-PAGE. The identity of these peptides as EDP was continued by immunoprecipitation and Western blots. The two-dimensional electrophoretic system can resolve desmosine-like cross-linked EDP of the similar molecular configuration but differing in the number of positively charged amino acid residues. The new separation technique of EDP has the capacity to identify defects in desmosine-like cross-links and may be useful in characterizing abberations in elastin structures.

Secondary aortoenteric fistulae--changes from 1973 to 1993

AIM

To investigate a series of patients with secondary aortoenteric fistulas and compare it with a previous series (1985-93 vs. 1973-84).

DESIGN

Retrospective study of medical records.

SETTING

Sixteen vascular surgical centers in Sweden.

PATIENTS

Twenty-seven patients were identified making an overall incidence of 0.5% of all aortoiliac operations. Among aneurysm patients the incidence was significantly lower than in the previous series. One patient record could not be identified. Fourteen primary operations were for aortic aneurysm, 12 for occlusive disease and one was an aortorenal vein bypass.

RESULTS

Symptoms of the fistula occurred after a median interval of 90 months which is significantly later than the previous series (32 months; p<0.05). The commonest presentation was bleeding followed by septis. The median diagnostic delay was 10.5 days, which was significantly shorter than in the previous series. Most fistulas involved the duodenum (88%). One patient died before surgery. The postoperative mortality was 28%, significantly lower than in the previous series (58%) (p<0.05). At the end of follow up (median 43 months) significantly more patients were alive than in the previous series (42% vs 18%) (p<0.05).

CONCLUSION

Over a 21 year period there seems to have been a decrease in the frequency of secondary aortoenteric fistulas after aneurysm surgery, a longer interval before they occur, a shorter diagnostic delay, and a better survival.

Memory dysfunction in mild aphasics

The effect of mild aphasia (n = 9), as a result of subarachnoid haemorrhage (SAH), was evaluated against one matched (sex, age, and education) control group suffering from SAH of unknown origin without aphasia, and against one matched healthy control group. According to aphasia testing (Reinvang & Engvik, 1980), criteria for a classical diagnosis were not met. Therefore, the patients were characterized as mild aphasics: They generally displayed intact audo-verbal comprehension and repetition abilities, and they demonstrated a fluent, spontaneous speech. However, they showed phonemic and semantic paraphasias, with self-corrections; a few patients displayed alexia and agraphia. Memory performance of these three groups was evaluated by a neuropsychological test battery, designed to tap various components of verbal memory function. From the results it was concluded that: (a) Short-term memory is impaired, as regards the phonological loop and the central executive in working memory, whereas maintenance rehearsal is unaffected, given that the demands on phonological coding is minimized, (b) long-term memory is also generally impaired, whereas long-term learning and forgetting by means of subject-performed tasks proceeds within a normal range. Impairments were hypothesized to reflect less efficient central executive functions of working memory, involving generation of less appropriate semantic codes and phonological representations, (c) mildly aphasic patients are not subjectively aware of their own memory deficits, and (d) aphasia classification by means of standard procedures do not sufficiently characterize the nature of a mildy aphasic patient's memory problems.

Human postburn oedema measured with the impression method

The course of tissue swelling in human non-injured skin after burn injury was investigated with a non-invasive impression method that measures force and tissue fluid translocation during mechanical compression of the skin. Time-dependent changes in the fluid translocation and the interstitial-pressure related to impression force were measured on 11 occasions, during 3 weeks, in seven patients postburn. A mathematical model was fitted to the impression force curves and the parameters of the model depicted the time-dependent compartmental fluid shift in the postburn generalized oedema. Tissue fluid translocation increased significantly (P < 0.05) up to a maximum value after 6 days postburn and declined thereafter. This indicated a continuous increase in the generalized postburn oedema for the first 6 days postburn. Impression force at 3 weeks postburn was significantly lower (P < 0.001) as compared with the half-day postburn value, indicating an increased tissue pressure during the first days postburn. Parameter analysis indicated a flux of water-like fluid from the vasculature to the interstitial space during the first 6 days postburn. The spread of the values registered between different measurement sites was, however, large.

Breast carcinoma growth rate described by mammographic doubling time and S-phase fraction. Correlations to clinical and histopathologic factors in a screened population

BACKGROUND

In a retrospective study, correlations among mammographic doubling times (DT), clinicopathologic prognostic factors, and cytometric predictors were examined.

METHODS

One hundred fifty-eight patients with the possibility to calculate mammographic tumor DT were selected and the tumors were histologically reexamined and flow cytometric analysis for ploidy and S-phase fraction (SPF) was performed.

RESULTS

The tumors were Stage I in 68%, and 45% were detected by mammographic screening. DT ranged from 0.6 months to an indefinite time (median, 9.0 months). Short DT was significantly correlated to large tumor size (P = 0.01) and advanced pathologic tumor stage (P = 0.016), but there was no correlation between DT and histologic grade. Ploidy analysis indicated that there were 57% aneuploid and 7% tetraploid tumors. There was a significant overrepresentation of euploid tumors among tumors smaller than 10 mm (P = 0.02). Ploidy was correlated to histologic grade (P less than 0.001) and DT (P = 0.009). SPF was calculated in 122 cases. SPF correlated significantly with pathologic stage (P = 0.002), tumor size (P = 0.037), histologic grade (P = 0.001), the presence of axillary lymph node metastases (P = 0.046), DT (P = 0.02), and DNA ploidy (P less than 0.001). Compared with interval carcinoma, screening-detected carcinoma showed favorable characteristics concerning size, stage, DT, ploidy, and SPF but not regarding histologic grade and axillary lymph node metastases.

CONCLUSIONS

DT shows great variations. Factors related to tumor biology (i.e., DT, DNA ploidy, and SPF) are strongly correlated with one another, but they have no correlation with axillary lymph node metastases. Cancer detected by screening is discovered at an early stage and shows favorable characteristics concerning DT, ploidy, and SPF.

Mammographic growth rate, DNA ploidy, and S-phase fraction analysis in breast carcinoma. A prognostic evaluation in a screened population

BACKGROUND

The authors examined prognostic factors in 158 cases of breast carcinoma with known mammographic tumor volume doubling times (DT).

METHODS

The tumors were retrospectively reexamined histologically and flow cytometric analysis of DNA ploidy and S-phase fraction (SPF) was performed on archival paraffin-embedded material in each case. Life tables and Cox multivariate analyses were used for statistical evaluation of prognostic factors.

RESULTS

In univariate analysis of survival data, clinical and pathologic stage, histologic grade, the presence of axillary lymph node metastases, and SPF were significant prognostic predictors, but mammographic DT and DNA ploidy were not. SPF also contributed prognostic information in the subgroup of carcinoma cases detected by screening. In a Cox multivariate analysis, SPF, the presence of axillary lymph node metastases, and Stage II-III disease (as opposed to Stage I disease) were independent significant predictors of survival. In univariate analyses of distant disease-free survival, clinical and pathologic stage, tumor size, histologic grade, the presence of involved axillary nodes, DT, and SPF all were significant prognostic factors.

CONCLUSIONS

SPF, stage, and lymph node status were important prognostic factors in this patient material with predominantly small and node-negative breast carcinomas, whereas DNA ploidy and mammographic DT provided less prognostic information. The prognosis of carcinoma detected during screening did not differ significantly from that of breast carcinoma discovered otherwise in this selected patient group.

Self-reported prevalence of disability after subarachnoid haemorrhage, with special emphasis on return to leisure and work

The prevalences of motor and language impairments and of disabilities in activities of daily living (ADL), leisure and work were investigated in a consecutive series (n = 296) of long-term survivors of subarachnoid haemorrhage (SAH). Motor and language impairments were present in 17 and 20%, respectively. The majority reported independence in self-care (91%) and instrumental (80%) ADL, but among the self-care independent, 23% reported need of personal assistance. Leisure disability occurred in 48% and vocational disability in 40%. Hence, disabilities are more common after SAH than is indicated by occurrences of motor and language impairments. It is concluded that the discrepancy between the prevalences of impairments and of disabilities may be to a great extent caused by coping difficulties in relation to socio-demographic and geographic circumstances. The findings indicate a need for rehabilitative follow-up for virtually all SAH-patients.

Evaluation of the impression technique by measuring interstitial oedema in rat testis

The impression method for assessment of subcutaneous oedema was evaluated in a rat testis model where the testicular interstitial fluid volume was changed both artificially by infusion of rat plasma and pharmacologically by administration of human chorionic gonadotrophin. Both the integral value and the impression force value, as measured with the impression method, changed with infused volume, and changes as small as 16 microliters (approximately 7% of the total interstitial fluid volume in a testis) could be detected. Rats were treated with a single injection of 100 i.u. human chorionic gonadotrophin in order to induce changes in the volume of interstitial fluid in the testis. Both the integral value and the impression force value seemed to reveal information on testicular interstitial fluid volume in rats treated with human chorionic gonadotrophin that was similar to data revealed by measuring the actual fluid content in the testis. Interstitial fluid volume measured morphometrically in the contralateral testis in human chorionic gonadotrophin-treated rats was significantly correlated to the impression force value (r = 0.75) and the integral value (r = 0.52). This rat testis model proved to be an interesting experimental set-up for evaluation of the impression technique.

Impression technique for the assessment of oedema. Technical improvement and methodological evaluation of a new technique

A new instrument for the assessment of oedema based on the impression method is described. The measurement parameters are defined and the errors corresponding to the electrical and mechanical stability of the instrument are measured. The overall accuracy is calculated theoretically for the translocated volume. The accuracy and reproducibility are evaluated on plastic foam. The clinical procedure to measure oedema with this instrument is described. We show that the accuracy of the translocated volume parameter is very dependent on the overall stability of the instrument and that this instrument has an overall relative error of less than 7.3 per cent for a representative measurement. Experimental measurements on plastic foam show that the measurement parameters could be reproduced with standard deviations of less than 6 per cent and that the standard deviations for translocated volume are within the calculated overall relative error. Measurements on four patients with chronic oedema in an extremity show significantly different results on locations where pitting could be recognised compared to the contralateral nonoedematous extremity.

Lp(a) lipoprotein in patients with arterial insufficiency of the lower extremities

The serum concentration of Lp(a) lipoprotein was determined in 66 patients with peripheral arterial insufficiency of the lower extremities (PAI) and 164 controls. The mean level was higher among the patients than among the controls (236 +/- 248 vs. 129 +/- 159 mg/l, p = 0.01), and values above 300 mg/l were more common among the patients (22/66 vs. 21/164, p less than 0.001). The difference between the 26 female patients and the 94 female controls was statistically significant (280 +/- 268 vs. 118 +/- 141 mg/l, p less than 0.001), but not the difference between the 40 male patients and the 70 male controls (208 +/- 235 vs. 142 +/- 182 mg/l). A high Lp(a) lipoprotein level was not associated with a high LDL-cholesterol level, and there was no significant correlation between the serum levels of Lp(a) lipoprotein and triglycerides++, total cholesterol or HDL-cholesterol. The results indicate, that high Lp(a) lipoprotein levels may be a risk factor for PAI in women.

Static and flow cytometric DNA analysis compared to histologic prognostic factors in a cohort of stage T2 breast cancer

DNA analysis with static and flow cytometry was performed on archival smears and tissue sections in 99 patients with T2 breast cancer (Stage II). Tumour size, histologic grade and axillary node metastases were significant prognostic predictors. Static cytometry revealed 63% aneuploid tumours, and ploidy was significantly correlated to histologic grade and survival. DNA measurements obtained by static and flow cytometry were strongly correlated. According to flow cytometry 53% of the tumours were aneuploid. Flow cytometric DNA analysis correlated to histologic grade and survival and gave prognostic information among the lymph-node negative patients. Ploidy seems to be a significant, although not an independent prognostic indicator for T2 breast cancer.

Fibre loss and distribution in skeletal muscle from patients with severe peripheral arterial insufficiency

Cross-sections of whole calf muscles (m soleus and m gastrocnemius) were obtained from five previously clinically health individuals who had died accidentally (controls) and from amputated legs of five patients of similar age with severe peripheral arterial insufficiency. In the controls, but not in the patients, a characteristic distribution of different fibre types over the entire cross-sections was found, with a relative increase in number of (slow twitch) type 1 fibres in the central parts of both m soleus and m gastrocnemius. A pronounced neuromuscular pathomorphology was found in the patients, especially in m gastrocnemius. The findings suggested widespread damage to the fibres. There was also a lower total number of fibres in these ischaemic muscles; about 50% of the fibres of m gastrocnemius seemed to have disappeared. The results suggested that the relative inactivity as such may be responsible for some of the structural changes, above all the dedifferentiated distribution of different fibres over the cross-section. However, repeated acute and chronic subacute ischaemia may also cause, in the long term, irreparable damage and loss of many individual fibres. This may explain why muscles of patients with peripheral arterial insufficiency are also weaker, during single contractions. The lack of corresponding muscular atrophy in these patients seems to a large extent to be explained by an increase in connective tissue.

Ultrasonographic screening of the abdominal aorta among siblings of patients with abdominal aortic aneurysms

To evaluate the prevalence of abdominal aortic dilatations among asymptomatic brothers and sisters of patients with abdominal aortic aneurysms (AAAs), an ultrasonographic screening study was performed. One hundred and two siblings of patients operated on for AAAs at two Swedish hospitals were invited to attend, and 87 of them (35 men and 52 women) from 32 different families, accepted the invitation. Their median age was 63 years (range 39-82 years). Aortic dilatation was diagnosed in ten of the brothers (29 per cent) and three of the sisters (6 per cent). In ten cases (eight men and two women) there was a localized dilatation caudal to the coeliac axis, and in three a general dilatation of the abdominal aorta with the diameter at the coeliac axis greater than 29 mm. None of the aortic dilatations had been known before this study was performed. The conclusion is that the prevalence of asymptomatic aortic dilatations among brothers of patients with AAAs seems to be high and that this group should be selected for further screening studies.

Verbal memory function after subarachnoid haemorrhage determined by the localisation of the ruptured aneurysm

A total of 219 patients who had suffered from subarachnoid haemorrhage (SAH) were given a set of memory tests. The tests comprised immediate free recall (indexing long-term memory, LTM, and short-term memory, STM), final free recall (LTM) and final cued recall (LTM) of words as well as a digit-span test (an index of working memory, WM). STM was highly sensitive to brain damage caused by SAH whereas WM was not. Localisation of the ruptured aneurysm, angiographic vasospasm or mass effect did not have any selective influence on the SAH group's STM or WM. The final free recall test was the most sensitive measure of LTM whereas the LTM part of the immediate free recall test was the least sensitive. LTM impairment was most pronounced for patients with ruptured left anterior communicating artery aneurysms or for patients with angiographic vasospasm or mass effect. It is suggested that, in the SAH patients, a passive phonological short-term store is impaired, but the active maintenance rehearsal mechanism is intact. For patients with LTM dysfunction, deeper, more elaborate, active processing is disrupted, hindering efficient long-term storage.

Peripheral arterial insufficiency and the fine structure of the gastrocnemius muscle

A detailed light- and electron microscopical study was carried out on biopsies from m. gastrocnemius of 14 male individuals with intermittent claudication. The morphometric data obtained showed a large number of significant correlations with clinical and physical parameters. Practically all sections also showed morphological abnormalities, such as a fibre necrosis, regeneration, angular fibres, fibre type grouping and abundant connective tissue. Finally, there were significant differences in the muscle fine structure between those patients recommended physical training and those selected for surgery. The results clearly show that the structure of the muscle fibres is well adapted to the functional circumstances. They also show that widespread fibre damage do occur in intermittently ischaemic musculature, even if no signs of macroscopical tissue damage are found at routine clinical examination. Furthermore, although the clinical and physical data on patients selected for physical training and vascular surgery respectively, are very similar, there seems to be other factors that clinically influence the differentiation of the patients into these two groups. When evaluating effects of different treatments on these two groups of patients, it is thus important to take into account that there may be differences in morphology even before they are subjected to the different treatments.

High concentrations of Lp(a) lipoprotein in serum are common among patients with abdominal aortic aneurysms

The serum concentrations of Lp(a) lipoprotein was determined in 57 patients with abdominal aortic aneurysms (AAAs) and in 56 controls. Twentynine of the AAA-patients also suffered from other cardiovascular diseases and eleven had brothers and sisters with AAAs. Lp(a) was significantly higher among the AAA-patients than among the controls (22.3 +/- 24.3 vs 12.6 +/- 20.4 mg/dl, p less than 0.01). The 28 AAA-patients without other cardiovascular diseases had a somewhat higher Lp(a) in serum than the other AAA-patients, but this difference was not statistically significant (26.4 +/- 28.4 vs 18.5 +/- 19.3 mg/dl). The 11 AAA-patients with AAAs in the family didn't differ from the other AAA-patients concerning Lp(a) in serum. Several genetic markers were also studied, and the seven Kell-positive AAA-patients had a significantly lower Lp(a) in serum than the 47 Kell-negative AAA-patients (7.0 +/- 10.3 vs 25.7 +/- 25.2 mg/dl, p less than 0.05).

Prognostic factors in locally advanced breast cancer (T3, T4) with special reference to tumor cell DNA content

The prognostic value of DNA analysis was studied retrospectively in 91 patients with locally advanced breast cancer (T3, T4) and a follow-up time of 3-7 years. Tumor cell DNA analysis was performed by static cytometry on aspiration biopsy specimens in 42 cases and on tissue sections in 49 cases. The tumors were classified as euploid or aneuploid. Sixty-four percent of the tumors were aneuploid. DNA pattern correlated significantly to histologic grade and axillary perinodal growth and also to survival. DNA pattern, histologic grade and axillary node metastases correlated significantly to disease-free survival (DFS). In this series of patients with locally advanced breast cancer DNA determinations gave important prognostic information.

Bile-salt-stimulated lipase in human milk: evidence for its synthesis in the lactating mammary gland

Human milk contains many enzymes and other biologically active proteins. One of the enzymes, the bile salt-stimulated lipase, constitutes as much as 1% of the milk proteins. Its importance for efficient utilization of milk lipids by the breast-fed infant is now well established. However, whether the lipase protein is a product of protein synthesis within the mammary gland has up till now been an unanswered question. Using biopsy material from lactating human mammary gland we have now demonstrated that the enzyme is synthesized within the gland. This was done by immunoprecipitation of [35S]methionine-labelled protein from tissue pieces. By activity determination we could also determine the amount of enzyme stored in the gland. It was concluded that bile salt-stimulated lipase accounted for 1.3 micrograms/mg tissue protein. Finally, from this figure it could be calculated that about 10-15% of the total protein present in the tissue was milk protein.

Intracranial aneurysms and heredity

The occurrence of intracranial aneurysms (IAs) in the families of 579 consecutive patients with subarachnoid hemorrhage (SAH), of whom 485 had verified IAs, was studied retrospectively. IAs occurred in the families of 6.7% of the IA patients, but only 0.4% of their siblings had IAs. However, there were differences between the familial and nonfamilial IA patients, indicating that the familial patients are a specific small subpopulation of IA patients. The familial patients were younger, often had multiple aneurysms, and had aneurysms frequently located on arteries other than those in the nonfamilial group.

Genetic markers in patients with intracranial aneurysms

HLA antigens, blood group systems (ABO, Rh, MNSs, P, Kell, Lewis and Duffy) and serum group systems (Hp, Tf, Gc, Pi, Bf, C3 and C4) were studied in a series of patients with intracranial aneurysms. A significantly increased frequency of HLA antigen A28, a significantly decreased frequency of HLA antigen B40, and a significantly decreased frequency of complement factor C4 B2 was found among the patients when compared with controls from the same geographic area.

Familial aortic aneurysms: serum concentrations of triglyceride, cholesterol, HDL-cholesterol and (VLDL + LDL)-cholesterol

Patients with abdominal aortic aneurysms (AAAs) have been compared with healthy controls with respect to the serum concentrations of triglyceride, cholesterol, HDL-cholesterol and (VLDL + LDL)-cholesterol. The concentrations of triglyceride and (VLDL + LDL)-cholesterol in serum were higher in the patients than in the controls, while the concentration of HDL-cholesterol in serum was lower in the patients than in the controls. There was no statistically significant difference in the serum concentration of total cholesterol between the patients and the controls. Twelve patients had first degree relatives (brothers, sisters and/or parents) with AAAs and six patients had second degree relatives (cousins or brothers and sisters of the parents) with AAAs. There was no statistically significant difference between the patients who had first degree relatives with AAAs and the patients without AAAs in the family in the serum concentrations of triglyceride, cholesterol, HDL-cholesterol and (VLDL + LDL)-cholesterol.

Familial occurrence of abdominal aortic aneurysms

The occurrence of clinically diagnosed and ruptured abdominal aortic aneurysms (AAAs) in the family was studied retrospectively among 200 consecutive patients with AAAs treated at the Surgical Clinic, University Hospital of Umeå, in the north of Sweden, during the period 1965 to 1981. A standardized questionnaire was sent to the 89 patients who were still alive when the study was performed, and 87 patients answered it. In 14 of these families there was one blood relative with AAA, and in two families there were two blood relatives with AAAs, apart from the proband. In nine cases AAAs occurred among the 468 brothers and sisters of the probands (1.9%), and in five cases among cousins. Seven of the 204 deceased brothers and sisters (3.4%) had died of ruptured AAAs. No questionnaires were sent to the families of the 111 deceased patients, but at least 11 of these patients had AAAs in the family. Pedigrees of the families with aggregation of aneurysms are presented, and fortuitous familial aggregation or predisposition to the development of AAAs is discussed.

Blood groups and HLA antigens in patients with abdominal aortic aneurysms

Frequencies of blood groups (ABO, Rh, MNSs, P, Kell, Lewis and Duffy) and HLA antigens were studied in a series of patients from northern Sweden with abdominal aortic aneurysms. The following significant differences from the controls were found: a decreased frequency of the Rh-negative blood group and increased frequencies of the Kell-positive and MN blood groups. Previously reported associations with the ABO and Rh systems were not confirmed.

Morphometric analyses of human muscle fiber types

Fibers from the m. vastus lateralis of 10 middle-aged men were classified at ultrastructural level according to the appearance of the sarcomeric M-band. The Z-band widths had a two-peak distribution. One peak was due to type 1 fibers (mean 125 +/- 11 nm), the other to type 2 fibers. This latter could be separated into type 2A (101 +/- 9 nm) and type 2B (86 +/- 8 nm). About 83% of the fibers would have been correctly classified on the basis of the Z-band width alone. Mitochondrial volumes differed (type 1 5.6 +/- 0.8, 2A 4.0 +/- 0.8, and 2B 2.8 +/- 0.8%). However, only one third (37%) of the fibers would have been correctly classified if sorted according to this parameter. Mitochondrial volumes in the different fibers were correlated to mitochondrial enzymes, while fiber sizes and numbers were correlated to cytoplasmic variables. The correlations appeared mainly after a training program, suggesting that the relationships between structural and functional parameters are more obvious after adaptation to higher functional demands.

Z- and M-band appearance in different histochemically defined types of human skeletal muscle fibers

In order to define ultrastructural features, which alone or in combination with other features could be used to identify different types of fibers in human skeletal muscle, frozen biopsy specimens of m. tibialis anterior were serially sectioned. The thawed sections were prepared either for enzyme histochemistry or for electron microscopy. The same fiber was then identified in all serial sections and its ultrastructure examined under the electron microscope. A total of 75 fibers were included in this investigation. Specimens were also conventionally prepared for electron microscopy. Special interest was devoted to the appearance of the sarcomeric Z- and M-bands. In the same fiber, all myofibrils showed the same Z- as well as M-band structure. On the other hand, it was evident that these structures varied from one type of fiber to another in the same muscle and that their appearance were covariant to a great extent. Low level resolution of Type 1 fibers usually showed broad Z- and M-bands with five strong M-bridge lines. In Type 2A fibers intermediate Z-bands were observed. In the middle portion of the M-bands, three strong M-bridge lines were distinct while the two outer lines were relatively weak. Finally, Type 2B fibers usually appeared with narrow Z-bands. The three M-bridge lines in the middle were strong while the two outer ones were very weak, if seen at all. Discriminant analysis showed that about 70% of the fibers should have been correctly allocated on the basis of the Z-band width alone. When two independent observers classified the fibers on the basis of M-band appearance, more than 95% of the fibers were correctly classified. Thus, both the Z- and M-bands, alone or in combination, can be used as fiber type discriminators. However, the M-band structure proved to be more reliable than the Z-band width, and should therefore be used as the fiber type indicator when only one of these parameters is considered.

Intermittent claudication and muscle fiber fine structure: morphometric data on mitochondrial volumes

The mitochondrial volume densities (Vmit) of the different fiber types (type 1, type 2A, type 2B) were estimated in bilaterally obtained biopsies from 22 patients with unilateral intermittent claudication. These data, which were obtained from structurally intact fibers, were compared with clinical data from the same subject. In both the asymptomatic and symptomatic legs, Vmit 1 greater than Vmit 2A greater than Vmit 2B. Furthermore, Vmit 1 covariated with Vmit 2A and Vmit 2A with Vmit 2B in the asymptomatic legs (as in healthy subjects) but not in the symptomatic legs. Vmit 2 (mainly Vmit 2A) covariated with the age of the subjects in both legs. Vmit Tot was higher in the symptomatic legs than in the asymptomatic legs. This was mainly due to increase in the oxidative fibers, type 1 and type 2A. Usually, Vmit in the asymptomatic legs covariated significantly with the results of the functional tests (initial pain and maximum walking tolerance), while only Vmit 2A in the symptomatic legs showed such a correlation. However, the difference between the two legs concerning Vmit 1 was also correlated to the walking tolerance. Patients with high stenosis or occlusion showed higher Vmit Tot than did those with low obstacles. The results conclusively show that a fiber type-specific adaptation to ischemia occurs through an increase of mitochondrial content of oxidative fibers, which suggests that hypoxia may influence the control of synthesis or degradation of mitochondrial proteins.