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Biomedical subjects

F Christ

Publications and source records attributed to F Christ.

At least 19 recordsLinked to original sources
PubMed1995

Investigating the origin of cyclic changes in limb volume using mercury-in-silastic strain gauge plethysmography in man.

1. Vasomotion, a phenomen frequently observed in skeletal muscle microcirculation, has been observed under physiological conditions and found enhanced during critical reduction of tissue perfusion due to hypoxic hypoxia, haemorrhage and local hypotension. We used a computer assisted non-invasive plethysmographic method to investigate periodic changes of limb volume (volumotion), which we previously found in critically ill patients. The current study was designed to investigate the origin of volumotion. 2. Simultaneous recordings of limb circumference of both calves were obtained. In patients with peripheral vascular disease and patients with minor surgery the cross-correlation with spontaneous breathing was investigated. In patients who had undergone major abdominal or vascular surgery we analysed for cross-correlations between MSG plethysmography signals of both legs and changes in central venous, arterial and ventilation pressures. In this group the effects of positive-pressure ventilation and positive end-expiratory pressure (PEEP) were also studied. 3. No ventilation-related volumotion was observed during spontaneous breathing. During positive-pressure ventilation a ventilation-related peak was found in the Fourier transform in agreement with the ventilation frequency applied. The amplitude of ventilation-related volumotion decreased significantly after a pressure cuff applied to the thigh was inflated above central venous pressure. We observed a significant increase in the amplitude of ventilation-related volumotion when PEEP was applied. 4. Ventilation-related volumotion showed significant cross-correlation between both legs. Slow wave volumotion (0.5-7 cycles min-1) was frequently observed, but always appeared unilaterally. Whilst we looked for correlations between slow wave volumotion and changes in central venous pressure and arterial blood pressure, respectively, significant cross-correlation with the MSG plethysmography recordings was only observed at the frequency of the positive-pressure ventilation. 5. The fact that periodic changes of limb circumference matching the frequency of the positive-pressure ventilation were detectable with the MSG plethysmography system demonstrates that small volume changes (less than 0.02 ml (100 ml tissue)-1) can be assessed using this system. As slow wave volumotion was observed unilaterally and revealed no correlation either with breathing, ventilation or arterial and central venous pressure, we suggest that slow wave volumotion is a local event most likely reflecting arteriolar vasomotion.

Aged↗
PubMed1994

The expression of GAP-43 and synaptophysin in the developing rat retina.

We have undertaken a detailed study of the expression of GAP-43 and synaptophysin immunoreactivity in the developing postnatal rat retina. We found that these two 'presynaptic' proteins have quite different expression patterns. GAP-43 was first expressed in the optic nerve and the optic fiber layer of the retina, where it disappeared between the 8th and 16th postnatal day. From the 5th postnatal day on, GAP-43 also appeared in the inner plexiform layer, where it was present in three distinct bands. This expression changed little in postnatal development and persisted in the adult retina. GAP-43 was not detected in the outer plexiform layer of the retina. Synaptophysin was absent from the optic nerve and optic fibers at all postnatal stages. It was first expressed in the developing outer plexiform and, with reduced intensity, in the outer nuclear layer between postnatal days 2 and 5. In the inner plexiform layer, synaptophysin could be first detected between postnatal days 8 and 12. The intensity of staining increased during postnatal development in both plexiform layers. The developmental sequence of synaptophysin expression can be correlated with the maturation of presynaptic terminals of photoreceptors and bipolar cells. The rather complex pattern of GAP-43 expression is not easily compatible with a single model of GAP-43 function, and suggests diverse functions of this molecule in the retina.

Animals↗
PubMed1993

A reassessment of mercury in silastic strain gauge plethysmography for microvascular permeability assessment in man.

1. We have used non-invasive mercury in a silastic strain gauge system to assess the effect of pressure step size, on the time course of the rapid volume response (RVR) to occlusion pressure. We also obtained values for hydraulic conductance (Kf), isovolumetric venous pressure (Pvi) and venous pressure (Pv) in thirty-five studies on the legs of twenty-three supine control subjects. 2. The initial rapid volume response to small (9.53 +/- 0.45 mmHg, mean +/- S.E.M.) stepped increases in venous pressure, the rapid volume response, could be described by a single exponential of time constant 15.54 +/- 1.14 s. 3. Increasing the size of the pressure step, to 49.8 +/- 1.1 mmHg, gave a larger value for the RVR time constant (mean 77.3 +/- 11.6 s). 4. We propose that the pressure-dependent difference in the duration of the rapid volume response, in these two situations, might be due to a vascular smooth muscle-based mechanism, e.g. the veni-arteriolar reflex. 5. The mean (+/- S.E.M.) values for Kf, Pvi and Pv were 4.27 +/- 0.18 (units, ml min-1 (100 g)-1 mmHg-1 x 10(-3), 21.50 +/- 0.81 (units, mmHg) and 9.11 +/- 0.94 (units, mmHg), respectively. 6. During simultaneous assessment of these parameters in arms and legs, it was found that they did not differ significantly from one another. 7. We propose that the mercury strain gauge system offers a useful, non-invasive means of studying the mechanisms governing fluid filtration in human limbs.

Arm↗
PubMed1993

Pneumocystis carinii infections in HIV-infected hemophiliacs during aerosolized pentamidine prophylaxis.

The frequency, presentation, diagnosis and clinical course of Pneumocystis carinii infections (PCI) were studied during aerosolized pentamidine prophylaxis (AP) and its impact on the spectrum of AIDS-related and other pulmonary infections in HIV-infected hemophiliacs. We conducted an open study on primary (PP) and secondary (SP) AP. Breakthrough P. carinii infections (BPCI) and other infectious complications were analyzed retrospectively. Hemophiliacs without prior P. carinii pneumonia (PCP) who had been reluctant to any prophylaxis and who developed PCP served as control group. Statistical analysis of the efficacy of prophylaxis was performed by calculating confidence intervals of binomial p. Of 73 hemophiliacs (56 on PP and 17 on SP) 10 developed BPCI (7 in PP and 3 in SP) during a mean observation time of 14.9 months (range 0.5-30); total 13.6% (6.7%; 23.7%), PP 12.5% (5.1%; 24%), SP 17.6% (3.7%; 43.4%), confidence intervals at a level of 95%. Three BPCI presented atypically with cavitation (1), pneumothorax (2), Pneumocystis pleuritis (1), dissemination (2) as compared to none in the control group. Sensitivity of bronchoalveolar lavage (BAL) was 88.9%, specificity 100% (both 100% in the control group). PCP was the leading AIDS manifestation (21.3%), CNS manifestations taken together were more frequent (36.2%). Bacterial pneumonia was the most frequent respiratory infection. One patient of the study group with recurrent pneumothorax possibly died of BPCI as compared to no BPCI-related deaths in the control group. Efficacy of prophylaxis in hemophiliacs was comparable to other risk groups. AP alone may be insufficient for the control of PCI in patients with long-term profound immunodeficiency, especially in SP. 30% of BPCI presented atypically.(ABSTRACT TRUNCATED AT 250 WORDS)

AIDS-Related Opportunistic Infections↗
PubMed1993

Pneumocystis carinii pneumonia presenting as an upper lobe cavity after aerosolized pentamidine prophylaxis in an HIV-infected patient.

We describe an atypical diagnostic feature of a breakthrough Pneumocystis carinii pneumonia (PCP) during primary prophylaxis with aerosolized pentamidine. Our case disclosed infiltrates restricted to the left upper lobe. After 2 weeks a solitary cavity developed. Diagnosis was easily established by bronchoalveolar lavage when performed in the affected segment bronchus. Cavitation clearly demonstrated localized infection, with tissue destruction as one main pathogenetic pattern of a breakthrough PCP during aerosolized pentamidine prophylaxis.

Adult↗
PubMed1993

[Microvascular monitoring using mercury in silastic strain gauge plethysmography (MSG)].

Mercury in silastic strain gauge plethysmography (MSG) is a noninvasive method for assessing microvascular parameters in peripheral limbs. MSG allows measurement of capillary filtration coefficient (Kf), isovolumetric venous pressure (Pvi), venous pressure (Pv) and arterial inflow (Qa) into the limb, respectively. We used MSG in combination with invasive monitoring techniques (pulmonary artery flotation catheters and arterial catheters) to study 36 critically ill patients in either hemorrhagic or septic shock. We observed marked increases in Pvi in both patient groups which correlated with outcome. On admission, both groups showed elevated values for Pvi, survivors 37.7 +/- 2.6, nonsurvivors 33.7 +/- 3.5 mm Hg (mean +/- SEM) when compared with a control group of young healthy students (22.1 +/- 0.82 mm Hg). Survivors showed a decrease in Pvi to 27.3 +/- 1.7 mm Hg, whereas in nonsurvivors Pvi increased to 39.5 +/- 3.0 at the last measurement taken. The changes in Pvi depended on the resuscitation regime used. On admission, patients requiring only fluid replacement (F) had a lower Pvi (31.3 +/- 2.9 mm Hg) than patients needing inotropic support with dobutamine (D, Pvi = 38.2 +/- 2.4 mm Hg) to fulfill our therapeutic goals (DO2 > 550 ml.min-1 x m-2, VO2 > 150 ml.min-1 x m-2 and mixed venous lactate < 1.5 mmol/l). After treatment Pvi did not change significantly in the F group (31.3 +/- 1.8), the D group however showed a significant decrease in Pvi to 25.4 +/- 2.42, which did not differ from the normal value. We regard Pvi as an indicator of insufficient microvascular flow.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

[Cryptogenetic ascites. Attempts at original pathophysiologic explanation of a monomorphic sonographic image pattern].

In 15,645 consecutive ultrasound examinations of the abdomen (1986 to 1988), free fluid in the peritoneal cavity was found in 247 patients by internal trial during 397 sessions (= 2.5%). Most frequent basic diagnosis for the reason of this symptom were tumorous diseases (99 patients corresponding to 40.1%), cirrhosis of the liver (52 patients corresp. to 22.1%) and heart failure (31 patients corresp. to 12.6%, among these complex gayprooft myocardial insufficiency 24, right heart failure 7). Ovarian cysts or cystomas (7), acute/chronic-recurrent pancreatitis (6), Crohn's disease (3), infections (3), rheumatoid disorders (3), nephrotic syndrome (2), and extra-uterine pregnancy (2) were more rarely represented. In 23 patients (corresp. to 9.3%) the cause of an ascites remained obscure. Among these, a high prevalence of the female sex in the premenopausal age was remarkable with a score of 20:3 (statistically significant difference in terms of the other patients of our group). This observation suggests that an ovarian factor plays a role in the development of ascites in the absence of other evident causes. The literature implies that endometriosis is rather prominent, followed by oligosymptomatic infections or inflammatory diseases.

Adolescent↗
PubMed1992

[A comparison of the value of magnetic resonance tomography and computed tomography in Nelson syndrome patients].

The hypophyses of 13 patients with Nelson syndrome following bilateral adrenalectomy were examined by MRI and CT. Diffuse enlargement of the hypophysis was demonstrated in 8 patients by CT and in 9 by MRI. Compared with CT, MRI provides better demonstration of tumour development, such as abnormal convexity of the cranial margin of the hypophysis (MRI 4/13, CT 1/13), displacement of the infundibulum (MRI 4/13, CT 0/13) or optic chiasm (MRI 2/13, CT 0/13). MRI also provides diagnostically important differentiation between scar tissue and recurrence of tumour following hypophysectomy (MRI 1/3, CT 0/3) and more accurate demonstration of infiltration of the cavernous sinus (MRI 4/13, CT 2/13). CT is superior only in showing the floor of the sella. MRI is the method of choice for imaging in cases of Nelson syndrome.

Adrenalectomy↗
PubMed1992

Mercury in silastic strain gauge plethysmography for the clinical assessment of the microcirculation.

We have used the mercury in silastic strain gauge plethysmography (MSG) system, which is wholly non-invasive, to obtain values (mean +/- s.e.m.) for the following parameters in the legs of supine control subjects: venous pressure (Pv) 9.89 +/- 0.88 mmHg, vascular compliance (Comp) 3.50 +/- 0.29 ml 100 g-1 mmHg-1 x 10(-2), microvascular hydraulic conductivity (Kf) 4.10 +/- 0.16 ml min-1 100 g-1 mmHg-1 x 10(-3) and isovolumetric venous pressure (Pvi) 22.12 +/- 0.82 mmHg. On passive foot-down tilting of control subjects through about 45 degrees, both Pv and Pvi rose to 28.00 +/- 2.33 and 36.58 +/- 2.29 mmHg respectively. The increases in both parameters were highly significant, P < 0.0001. We found that the time course of the vascular compliance component was short if small pressure steps were used. The value increased markedly if large steps were used. We also observed that none of the microvascular parameters studied in the arms differed from those in the legs of the same subjects. We observed that the mean value Kf in the arms of 12 young, non-neuropathic diabetics (9.08 +/- 6.12 x 10(-3)) was significantly greater than that of age and sex-matched controls (P < 0.001). Studies on 14 venous ulceration patients indicated that the values for Kf and Pv were unchanged, whilst those of vascular compliance (5.60 +/- 0.58 x 10(-2) ml 100 g-1 mmHg-1) and Pvi (37.30 +/- 2.25 mmHg) were significantly greater than those found in age-matched controls (P < 0.002 and 0.001, respectively). We feel that Pvi is a useful index of microvascular perfusion. We attribute the pressure-dependent difference, in the time course of the vascular compliance response, to the veni-arteriolar reflex. We feel that the pressure dependency of this response might form the basis for the assessment of peripheral autonomic neuropathy. We believe that the MSG system offers a means of monitoring the development of pathologies resulting from microvascular under-perfusion and, of course, the improvement in response to therapeutic interventions.

Adult↗
PubMed1991

[Spontaneous regression of liver metastases in neuroendocrine tumors of the abdomen].

In six patients with hepatically metastasised gastrointestinal tumours of neuro-endocrinal origin, including one each islet cell carcinoma and gastrinoma of the pancreas, one cloacogenic carcinoma (a rare type of anal cancer), and three carcinoid tumours of the small bowel, spontaneous liquefaction inside echogenic liver metastases was demonstrated by ultrasound. The hepatic lesions were classified as being of "bull's-eye-" shape without "badge" pattern. Chemotherapy had no effect on their ultrasonographic imaging. With regard to our observations, liquefying processes were far more common in these well-differentiated tumour metastases than in poorly differentiated fast-proliferating malignancies (about 1:40). Assessment of liquefaction, however, has obviously no influence on the prognosis of progress speed. Ultrasonographic differential diagnosis includes focal inflammatory disease of the liver, if there is no evidence of a primary tumour.

Carcinoid Tumor↗
PubMed1991

[The radiological image of pleural lipomas with special reference to computed tomography].

Diagnostic assessment of focal pleural mass requires CT examination, particularly in follow-up of anamnestic tumour conditions. Since 1976 well-delineated pleural masses that were suspicious for malignancy on chest films, were identified in 11 patients as lipomas, using CT. They showed semicircular, oval or polygonal shape, but no really "spheric" aspect on biplane chest films. Main diameters of these masses were 2.5 to 6 cm and only once 11 cm. Density values mostly ranged from -110 to -70 HE (min. -133, max. -22 HE) in nonenhanced CT studies. Findings were localised adjacent to the parietal pleura seven times (in one patient two separate findings) and to the diaphragmatic pleura five times. In 7751 CT examinations of the chest, the incidence of pleural lipomas was 0.14%, their prevalence concerning solid pleural lesions being 5.3%. Among all intrathoracic lipomas those in mediastinal and paracardial location respectively were definitely more often (30 patients).

Aged↗
PubMed1991

The assessment of the microcirculatory effects of dobutamine using mercury in silastic strain gauge plethysmography in man.

Adverse changes in the microcirculation are currently considered as the most likely common pathway of organ failure, dramatically manifest in the multiple organ failure syndrome. We have investigated 28 patients presenting with gross cardiovascular instability due to septic shock or haemorrhage, using standard invasive methods of monitoring (Physiological Profile). We combined this study with a computer assisted mercury-in-rubber strain gauge plethysmography (MSG) measurement, for a parallel (non-invasive) assessment of peripheral microcirculatory function. We started the investigation on patient arrival in ICU and continued it during their resuscitation regime, which essentially consisted of fluid loading together with inotropic support, where necessary. We found highly significant changes in isovolumetric venous pressure (Pvi), determined by the MSG technique, when we compared survivors (27.29 +/- 1.65 mmHg, mean +/- s.e.m.) with non-survivors (39.5 +/- 2.97 mmHg, P less than 0.001). To investigate the role of dobutamine in patient improvement we compared the Pvi values obtained from the MSG studies and demonstrated a significant decrease from the initial value (38.2 +/- 2.4 mmHg) to the final one (25.4 +/- 2.4 mmHg), obtained after weaning the patients off dobutamine. Marked cyclic changes in limb circumference (vasomotion) were also observed and their appearance correlated well with accepted parameters of cardiovascular instability. We propose that changes in both Pvi and Vm are useful indices of microvascular hypoperfusion which is probably the underlying cause of pathology in both patient groups.

Dobutamine↗
PubMed1990

[A pseudosarcoma of the duodenum].

Pseudosarcoma is a rare malignant neoplasm composed of both carcinomatous and sarcomatous elements. It occurs most frequently in the uterus. When located in the gastrointestinal tract the lethality is almost 100% one year after the diagnosis. Clinical observations and radiological findings in a 52-year old patient with pseudosarcoma of the duodenum are presented in this report.

Carcinosarcoma↗
PubMed1990

[Juvenile occlusion syndrome of the inferior vena cava with left renal deficiency].

In three juvenile patients, one female and two males aged 14 to 21 years, there were recent deep vein thromboses of the lower limbs due to previous infrahepatic occlusion of the inferior vena cava associated with a shrunken left kidney without clinical manifestation of a nephrotic syndrome. Possible reasons and impacts of this probably congenital peculiar vascular syndrome are discussed. Radiodiagnostic management in juvenile patients with recurrent venous thromboses of the lower part of the body is explained with special respect to secondary phenomena of other retroperitoneal organs like adrenals, inner pelvis and testicles.

Adolescent↗
PubMed1989

[Exertional dyspnea, chest pain, dizziness].

A 66 year old patient with chest pain and exertional dyspnea is described. Auscultation and physical examination showed signs of aortic stenosis combined with aortic insufficiency. Electrocardiography revealed left ventricular hypertrophy with associated ST-segment and T-wave abnormalities. Color blood flow imaging confirmed severe combined aortic stenosis and regurgitation, the hemodynamic evaluation demonstrated the indication for aortic valve replacement.

Aged↗